1 2<!DOCTYPE html> 3 4<html> 5 <head> 6 <meta charset="utf-8" /> 7 <meta name="viewport" content="width=device-width, initial-scale=1.0" /> 8 <title>IDLE — Python 3.10.0a1 documentation</title> 9 <link rel="stylesheet" href="../_static/pydoctheme.css" type="text/css" /> 10 <link rel="stylesheet" href="../_static/pygments.css" type="text/css" /> 11 12 <script id="documentation_options" data-url_root="../" src="../_static/documentation_options.js"></script> 13 <script src="../_static/jquery.js"></script> 14 <script src="../_static/underscore.js"></script> 15 <script src="../_static/doctools.js"></script> 16 <script src="../_static/language_data.js"></script> 17 18 <script src="../_static/sidebar.js"></script> 19 20 <link rel="search" type="application/opensearchdescription+xml" 21 title="Search within Python 3.10.0a1 documentation" 22 href="../_static/opensearch.xml"/> 23 <link rel="author" title="About these documents" href="../about.html" /> 24 <link rel="index" title="Index" href="../genindex.html" /> 25 <link rel="search" title="Search" href="../search.html" /> 26 <link rel="copyright" title="Copyright" href="../copyright.html" /> 27 <link rel="next" title="Other Graphical User Interface Packages" href="othergui.html" /> 28 <link rel="prev" title="tkinter.tix — Extension widgets for Tk" href="tkinter.tix.html" /> 29 <link rel="canonical" href="https://docs.python.org/3/library/idle.html" /> 30 31 32 33 34 35 36 <style> 37 @media only screen { 38 table.full-width-table { 39 width: 100%; 40 } 41 } 42 </style> 43 44 <link rel="shortcut icon" type="image/png" href="../_static/py.png" /> 45 46 <script type="text/javascript" src="../_static/copybutton.js"></script> 47 48 49 50 51 </head><body> 52 53 <div class="related" role="navigation" aria-label="related navigation"> 54 <h3>Navigation</h3> 55 <ul> 56 <li class="right" style="margin-right: 10px"> 57 <a href="../genindex.html" title="General Index" 58 accesskey="I">index</a></li> 59 <li class="right" > 60 <a href="../py-modindex.html" title="Python Module Index" 61 >modules</a> |</li> 62 <li class="right" > 63 <a href="othergui.html" title="Other Graphical User Interface Packages" 64 accesskey="N">next</a> |</li> 65 <li class="right" > 66 <a href="tkinter.tix.html" title="tkinter.tix — Extension widgets for Tk" 67 accesskey="P">previous</a> |</li> 68 69 <li><img src="../_static/py.png" alt="" 70 style="vertical-align: middle; margin-top: -1px"/></li> 71 <li><a href="https://www.python.org/">Python</a> »</li> 72 73 74 <li> 75 <a href="../index.html">3.10.0a1 Documentation</a> » 76 </li> 77 78 <li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> »</li> 79 <li class="nav-item nav-item-2"><a href="tk.html" accesskey="U">Graphical User Interfaces with Tk</a> »</li> 80 <li class="nav-item nav-item-this"><a href="">IDLE</a></li> 81 <li class="right"> 82 83 84 <div class="inline-search" style="display: none" role="search"> 85 <form class="inline-search" action="../search.html" method="get"> 86 <input placeholder="Quick search" type="text" name="q" /> 87 <input type="submit" value="Go" /> 88 <input type="hidden" name="check_keywords" value="yes" /> 89 <input type="hidden" name="area" value="default" /> 90 </form> 91 </div> 92 <script type="text/javascript">$('.inline-search').show(0);</script> 93 | 94 </li> 95 96 </ul> 97 </div> 98 99 <div class="document"> 100 <div class="documentwrapper"> 101 <div class="bodywrapper"> 102 <div class="body" role="main"> 103 104 <div class="section" id="idle"> 105<span id="id1"></span><h1>IDLE<a class="headerlink" href="#idle" title="Permalink to this headline">¶</a></h1> 106<p><strong>Source code:</strong> <a class="reference external" href="https://github.com/python/cpython/tree/master/Lib/idlelib/">Lib/idlelib/</a></p> 107<hr class="docutils" id="index-0" /> 108<p>IDLE is Python’s Integrated Development and Learning Environment.</p> 109<p>IDLE has the following features:</p> 110<ul class="simple"> 111<li><p>coded in 100% pure Python, using the <a class="reference internal" href="tkinter.html#module-tkinter" title="tkinter: Interface to Tcl/Tk for graphical user interfaces"><code class="xref py py-mod docutils literal notranslate"><span class="pre">tkinter</span></code></a> GUI toolkit</p></li> 112<li><p>cross-platform: works mostly the same on Windows, Unix, and macOS</p></li> 113<li><p>Python shell window (interactive interpreter) with colorizing 114of code input, output, and error messages</p></li> 115<li><p>multi-window text editor with multiple undo, Python colorizing, 116smart indent, call tips, auto completion, and other features</p></li> 117<li><p>search within any window, replace within editor windows, and search 118through multiple files (grep)</p></li> 119<li><p>debugger with persistent breakpoints, stepping, and viewing 120of global and local namespaces</p></li> 121<li><p>configuration, browsers, and other dialogs</p></li> 122</ul> 123<div class="section" id="menus"> 124<h2>Menus<a class="headerlink" href="#menus" title="Permalink to this headline">¶</a></h2> 125<p>IDLE has two main window types, the Shell window and the Editor window. It is 126possible to have multiple editor windows simultaneously. On Windows and 127Linux, each has its own top menu. Each menu documented below indicates 128which window type it is associated with.</p> 129<p>Output windows, such as used for Edit => Find in Files, are a subtype of editor 130window. They currently have the same top menu but a different 131default title and context menu.</p> 132<p>On macOS, there is one application menu. It dynamically changes according 133to the window currently selected. It has an IDLE menu, and some entries 134described below are moved around to conform to Apple guidelines.</p> 135<div class="section" id="file-menu-shell-and-editor"> 136<h3>File menu (Shell and Editor)<a class="headerlink" href="#file-menu-shell-and-editor" title="Permalink to this headline">¶</a></h3> 137<dl class="simple"> 138<dt>New File</dt><dd><p>Create a new file editing window.</p> 139</dd> 140<dt>Open…</dt><dd><p>Open an existing file with an Open dialog.</p> 141</dd> 142<dt>Recent Files</dt><dd><p>Open a list of recent files. Click one to open it.</p> 143</dd> 144<dt>Open Module…</dt><dd><p>Open an existing module (searches sys.path).</p> 145</dd> 146</dl> 147<dl class="simple" id="index-1"> 148<dt>Class Browser</dt><dd><p>Show functions, classes, and methods in the current Editor file in a 149tree structure. In the shell, open a module first.</p> 150</dd> 151<dt>Path Browser</dt><dd><p>Show sys.path directories, modules, functions, classes and methods in a 152tree structure.</p> 153</dd> 154<dt>Save</dt><dd><p>Save the current window to the associated file, if there is one. Windows 155that have been changed since being opened or last saved have a * before 156and after the window title. If there is no associated file, 157do Save As instead.</p> 158</dd> 159<dt>Save As…</dt><dd><p>Save the current window with a Save As dialog. The file saved becomes the 160new associated file for the window.</p> 161</dd> 162<dt>Save Copy As…</dt><dd><p>Save the current window to different file without changing the associated 163file.</p> 164</dd> 165<dt>Print Window</dt><dd><p>Print the current window to the default printer.</p> 166</dd> 167<dt>Close</dt><dd><p>Close the current window (ask to save if unsaved).</p> 168</dd> 169<dt>Exit</dt><dd><p>Close all windows and quit IDLE (ask to save unsaved windows).</p> 170</dd> 171</dl> 172</div> 173<div class="section" id="edit-menu-shell-and-editor"> 174<h3>Edit menu (Shell and Editor)<a class="headerlink" href="#edit-menu-shell-and-editor" title="Permalink to this headline">¶</a></h3> 175<dl class="simple"> 176<dt>Undo</dt><dd><p>Undo the last change to the current window. A maximum of 1000 changes may 177be undone.</p> 178</dd> 179<dt>Redo</dt><dd><p>Redo the last undone change to the current window.</p> 180</dd> 181<dt>Cut</dt><dd><p>Copy selection into the system-wide clipboard; then delete the selection.</p> 182</dd> 183<dt>Copy</dt><dd><p>Copy selection into the system-wide clipboard.</p> 184</dd> 185<dt>Paste</dt><dd><p>Insert contents of the system-wide clipboard into the current window.</p> 186</dd> 187</dl> 188<p>The clipboard functions are also available in context menus.</p> 189<dl class="simple"> 190<dt>Select All</dt><dd><p>Select the entire contents of the current window.</p> 191</dd> 192<dt>Find…</dt><dd><p>Open a search dialog with many options</p> 193</dd> 194<dt>Find Again</dt><dd><p>Repeat the last search, if there is one.</p> 195</dd> 196<dt>Find Selection</dt><dd><p>Search for the currently selected string, if there is one.</p> 197</dd> 198<dt>Find in Files…</dt><dd><p>Open a file search dialog. Put results in a new output window.</p> 199</dd> 200<dt>Replace…</dt><dd><p>Open a search-and-replace dialog.</p> 201</dd> 202<dt>Go to Line</dt><dd><p>Move the cursor to the beginning of the line requested and make that 203line visible. A request past the end of the file goes to the end. 204Clear any selection and update the line and column status.</p> 205</dd> 206<dt>Show Completions</dt><dd><p>Open a scrollable list allowing selection of existing names. See 207<a class="reference internal" href="#completions"><span class="std std-ref">Completions</span></a> in the Editing and navigation section below.</p> 208</dd> 209<dt>Expand Word</dt><dd><p>Expand a prefix you have typed to match a full word in the same window; 210repeat to get a different expansion.</p> 211</dd> 212<dt>Show call tip</dt><dd><p>After an unclosed parenthesis for a function, open a small window with 213function parameter hints. See <a class="reference internal" href="#calltips"><span class="std std-ref">Calltips</span></a> in the 214Editing and navigation section below.</p> 215</dd> 216<dt>Show surrounding parens</dt><dd><p>Highlight the surrounding parenthesis.</p> 217</dd> 218</dl> 219</div> 220<div class="section" id="format-menu-editor-window-only"> 221<span id="format-menu"></span><h3>Format menu (Editor window only)<a class="headerlink" href="#format-menu-editor-window-only" title="Permalink to this headline">¶</a></h3> 222<dl class="simple"> 223<dt>Indent Region</dt><dd><p>Shift selected lines right by the indent width (default 4 spaces).</p> 224</dd> 225<dt>Dedent Region</dt><dd><p>Shift selected lines left by the indent width (default 4 spaces).</p> 226</dd> 227<dt>Comment Out Region</dt><dd><p>Insert ## in front of selected lines.</p> 228</dd> 229<dt>Uncomment Region</dt><dd><p>Remove leading # or ## from selected lines.</p> 230</dd> 231<dt>Tabify Region</dt><dd><p>Turn <em>leading</em> stretches of spaces into tabs. (Note: We recommend using 2324 space blocks to indent Python code.)</p> 233</dd> 234<dt>Untabify Region</dt><dd><p>Turn <em>all</em> tabs into the correct number of spaces.</p> 235</dd> 236<dt>Toggle Tabs</dt><dd><p>Open a dialog to switch between indenting with spaces and tabs.</p> 237</dd> 238<dt>New Indent Width</dt><dd><p>Open a dialog to change indent width. The accepted default by the Python 239community is 4 spaces.</p> 240</dd> 241<dt>Format Paragraph</dt><dd><p>Reformat the current blank-line-delimited paragraph in comment block or 242multiline string or selected line in a string. All lines in the 243paragraph will be formatted to less than N columns, where N defaults to 72.</p> 244</dd> 245<dt>Strip trailing whitespace</dt><dd><p>Remove trailing space and other whitespace characters after the last 246non-whitespace character of a line by applying str.rstrip to each line, 247including lines within multiline strings. Except for Shell windows, 248remove extra newlines at the end of the file.</p> 249</dd> 250</dl> 251</div> 252<div class="section" id="run-menu-editor-window-only"> 253<span id="index-2"></span><h3>Run menu (Editor window only)<a class="headerlink" href="#run-menu-editor-window-only" title="Permalink to this headline">¶</a></h3> 254<dl class="simple" id="run-module"> 255<dt>Run Module</dt><dd><p>Do <a class="reference internal" href="#check-module"><span class="std std-ref">Check Module</span></a>. If no error, restart the shell to clean the 256environment, then execute the module. Output is displayed in the Shell 257window. Note that output requires use of <code class="docutils literal notranslate"><span class="pre">print</span></code> or <code class="docutils literal notranslate"><span class="pre">write</span></code>. 258When execution is complete, the Shell retains focus and displays a prompt. 259At this point, one may interactively explore the result of execution. 260This is similar to executing a file with <code class="docutils literal notranslate"><span class="pre">python</span> <span class="pre">-i</span> <span class="pre">file</span></code> at a command 261line.</p> 262</dd> 263</dl> 264<dl class="simple" id="run-custom"> 265<dt>Run… Customized</dt><dd><p>Same as <a class="reference internal" href="#run-module"><span class="std std-ref">Run Module</span></a>, but run the module with customized 266settings. <em>Command Line Arguments</em> extend <a class="reference internal" href="sys.html#sys.argv" title="sys.argv"><code class="xref py py-data docutils literal notranslate"><span class="pre">sys.argv</span></code></a> as if passed 267on a command line. The module can be run in the Shell without restarting.</p> 268</dd> 269</dl> 270<dl class="simple" id="check-module"> 271<dt>Check Module</dt><dd><p>Check the syntax of the module currently open in the Editor window. If the 272module has not been saved IDLE will either prompt the user to save or 273autosave, as selected in the General tab of the Idle Settings dialog. If 274there is a syntax error, the approximate location is indicated in the 275Editor window.</p> 276</dd> 277</dl> 278<dl class="simple" id="python-shell"> 279<dt>Python Shell</dt><dd><p>Open or wake up the Python Shell window.</p> 280</dd> 281</dl> 282</div> 283<div class="section" id="shell-menu-shell-window-only"> 284<h3>Shell menu (Shell window only)<a class="headerlink" href="#shell-menu-shell-window-only" title="Permalink to this headline">¶</a></h3> 285<dl class="simple"> 286<dt>View Last Restart</dt><dd><p>Scroll the shell window to the last Shell restart.</p> 287</dd> 288<dt>Restart Shell</dt><dd><p>Restart the shell to clean the environment.</p> 289</dd> 290<dt>Previous History</dt><dd><p>Cycle through earlier commands in history which match the current entry.</p> 291</dd> 292<dt>Next History</dt><dd><p>Cycle through later commands in history which match the current entry.</p> 293</dd> 294<dt>Interrupt Execution</dt><dd><p>Stop a running program.</p> 295</dd> 296</dl> 297</div> 298<div class="section" id="debug-menu-shell-window-only"> 299<h3>Debug menu (Shell window only)<a class="headerlink" href="#debug-menu-shell-window-only" title="Permalink to this headline">¶</a></h3> 300<dl class="simple"> 301<dt>Go to File/Line</dt><dd><p>Look on the current line. with the cursor, and the line above for a filename 302and line number. If found, open the file if not already open, and show the 303line. Use this to view source lines referenced in an exception traceback 304and lines found by Find in Files. Also available in the context menu of 305the Shell window and Output windows.</p> 306</dd> 307</dl> 308<dl class="simple" id="index-3"> 309<dt>Debugger (toggle)</dt><dd><p>When activated, code entered in the Shell or run from an Editor will run 310under the debugger. In the Editor, breakpoints can be set with the context 311menu. This feature is still incomplete and somewhat experimental.</p> 312</dd> 313<dt>Stack Viewer</dt><dd><p>Show the stack traceback of the last exception in a tree widget, with 314access to locals and globals.</p> 315</dd> 316<dt>Auto-open Stack Viewer</dt><dd><p>Toggle automatically opening the stack viewer on an unhandled exception.</p> 317</dd> 318</dl> 319</div> 320<div class="section" id="options-menu-shell-and-editor"> 321<h3>Options menu (Shell and Editor)<a class="headerlink" href="#options-menu-shell-and-editor" title="Permalink to this headline">¶</a></h3> 322<dl class="simple"> 323<dt>Configure IDLE</dt><dd><p>Open a configuration dialog and change preferences for the following: 324fonts, indentation, keybindings, text color themes, startup windows and 325size, additional help sources, and extensions. On macOS, open the 326configuration dialog by selecting Preferences in the application 327menu. For more details, see 328<a class="reference internal" href="#preferences"><span class="std std-ref">Setting preferences</span></a> under Help and preferences.</p> 329</dd> 330</dl> 331<p>Most configuration options apply to all windows or all future windows. 332The option items below only apply to the active window.</p> 333<dl class="simple"> 334<dt>Show/Hide Code Context (Editor Window only)</dt><dd><p>Open a pane at the top of the edit window which shows the block context 335of the code which has scrolled above the top of the window. See 336<a class="reference internal" href="#code-context"><span class="std std-ref">Code Context</span></a> in the Editing and Navigation section 337below.</p> 338</dd> 339<dt>Show/Hide Line Numbers (Editor Window only)</dt><dd><p>Open a column to the left of the edit window which shows the number 340of each line of text. The default is off, which may be changed in the 341preferences (see <a class="reference internal" href="#preferences"><span class="std std-ref">Setting preferences</span></a>).</p> 342</dd> 343<dt>Zoom/Restore Height</dt><dd><p>Toggles the window between normal size and maximum height. The initial size 344defaults to 40 lines by 80 chars unless changed on the General tab of the 345Configure IDLE dialog. The maximum height for a screen is determined by 346momentarily maximizing a window the first time one is zoomed on the screen. 347Changing screen settings may invalidate the saved height. This toggle has 348no effect when a window is maximized.</p> 349</dd> 350</dl> 351</div> 352<div class="section" id="window-menu-shell-and-editor"> 353<h3>Window menu (Shell and Editor)<a class="headerlink" href="#window-menu-shell-and-editor" title="Permalink to this headline">¶</a></h3> 354<p>Lists the names of all open windows; select one to bring it to the foreground 355(deiconifying it if necessary).</p> 356</div> 357<div class="section" id="help-menu-shell-and-editor"> 358<h3>Help menu (Shell and Editor)<a class="headerlink" href="#help-menu-shell-and-editor" title="Permalink to this headline">¶</a></h3> 359<dl class="simple"> 360<dt>About IDLE</dt><dd><p>Display version, copyright, license, credits, and more.</p> 361</dd> 362<dt>IDLE Help</dt><dd><p>Display this IDLE document, detailing the menu options, basic editing and 363navigation, and other tips.</p> 364</dd> 365<dt>Python Docs</dt><dd><p>Access local Python documentation, if installed, or start a web browser 366and open docs.python.org showing the latest Python documentation.</p> 367</dd> 368<dt>Turtle Demo</dt><dd><p>Run the turtledemo module with example Python code and turtle drawings.</p> 369</dd> 370</dl> 371<p>Additional help sources may be added here with the Configure IDLE dialog under 372the General tab. See the <a class="reference internal" href="#help-sources"><span class="std std-ref">Help sources</span></a> subsection below 373for more on Help menu choices.</p> 374</div> 375<div class="section" id="context-menus"> 376<span id="index-4"></span><h3>Context Menus<a class="headerlink" href="#context-menus" title="Permalink to this headline">¶</a></h3> 377<p>Open a context menu by right-clicking in a window (Control-click on macOS). 378Context menus have the standard clipboard functions also on the Edit menu.</p> 379<dl class="simple"> 380<dt>Cut</dt><dd><p>Copy selection into the system-wide clipboard; then delete the selection.</p> 381</dd> 382<dt>Copy</dt><dd><p>Copy selection into the system-wide clipboard.</p> 383</dd> 384<dt>Paste</dt><dd><p>Insert contents of the system-wide clipboard into the current window.</p> 385</dd> 386</dl> 387<p>Editor windows also have breakpoint functions. Lines with a breakpoint set are 388specially marked. Breakpoints only have an effect when running under the 389debugger. Breakpoints for a file are saved in the user’s <code class="docutils literal notranslate"><span class="pre">.idlerc</span></code> 390directory.</p> 391<dl class="simple"> 392<dt>Set Breakpoint</dt><dd><p>Set a breakpoint on the current line.</p> 393</dd> 394<dt>Clear Breakpoint</dt><dd><p>Clear the breakpoint on that line.</p> 395</dd> 396</dl> 397<p>Shell and Output windows also have the following.</p> 398<dl class="simple"> 399<dt>Go to file/line</dt><dd><p>Same as in Debug menu.</p> 400</dd> 401</dl> 402<p>The Shell window also has an output squeezing facility explained in the <em>Python 403Shell window</em> subsection below.</p> 404<dl class="simple"> 405<dt>Squeeze</dt><dd><p>If the cursor is over an output line, squeeze all the output between 406the code above and the prompt below down to a ‘Squeezed text’ label.</p> 407</dd> 408</dl> 409</div> 410</div> 411<div class="section" id="editing-and-navigation"> 412<span id="id2"></span><h2>Editing and navigation<a class="headerlink" href="#editing-and-navigation" title="Permalink to this headline">¶</a></h2> 413<div class="section" id="editor-windows"> 414<h3>Editor windows<a class="headerlink" href="#editor-windows" title="Permalink to this headline">¶</a></h3> 415<p>IDLE may open editor windows when it starts, depending on settings 416and how you start IDLE. Thereafter, use the File menu. There can be only 417one open editor window for a given file.</p> 418<p>The title bar contains the name of the file, the full path, and the version 419of Python and IDLE running the window. The status bar contains the line 420number (‘Ln’) and column number (‘Col’). Line numbers start with 1; 421column numbers with 0.</p> 422<p>IDLE assumes that files with a known .py* extension contain Python code 423and that other files do not. Run Python code with the Run menu.</p> 424</div> 425<div class="section" id="key-bindings"> 426<h3>Key bindings<a class="headerlink" href="#key-bindings" title="Permalink to this headline">¶</a></h3> 427<p>In this section, ‘C’ refers to the <kbd class="kbd docutils literal notranslate">Control</kbd> key on Windows and Unix and 428the <kbd class="kbd docutils literal notranslate">Command</kbd> key on macOS.</p> 429<ul> 430<li><p><kbd class="kbd docutils literal notranslate">Backspace</kbd> deletes to the left; <kbd class="kbd docutils literal notranslate">Del</kbd> deletes to the right</p></li> 431<li><p><kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">C</kbd>-<kbd class="kbd docutils literal notranslate">Backspace</kbd></kbd> delete word left; <kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">C</kbd>-<kbd class="kbd docutils literal notranslate">Del</kbd></kbd> delete word to the right</p></li> 432<li><p>Arrow keys and <kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">Page</kbd> <kbd class="kbd docutils literal notranslate">Up</kbd></kbd>/<kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">Page</kbd> <kbd class="kbd docutils literal notranslate">Down</kbd></kbd> to move around</p></li> 433<li><p><kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">C</kbd>-<kbd class="kbd docutils literal notranslate">LeftArrow</kbd></kbd> and <kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">C</kbd>-<kbd class="kbd docutils literal notranslate">RightArrow</kbd></kbd> moves by words</p></li> 434<li><p><kbd class="kbd docutils literal notranslate">Home</kbd>/<kbd class="kbd docutils literal notranslate">End</kbd> go to begin/end of line</p></li> 435<li><p><kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">C</kbd>-<kbd class="kbd docutils literal notranslate">Home</kbd></kbd>/<kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">C</kbd>-<kbd class="kbd docutils literal notranslate">End</kbd></kbd> go to begin/end of file</p></li> 436<li><p>Some useful Emacs bindings are inherited from Tcl/Tk:</p> 437<blockquote> 438<div><ul class="simple"> 439<li><p><kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">C</kbd>-<kbd class="kbd docutils literal notranslate">a</kbd></kbd> beginning of line</p></li> 440<li><p><kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">C</kbd>-<kbd class="kbd docutils literal notranslate">e</kbd></kbd> end of line</p></li> 441<li><p><kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">C</kbd>-<kbd class="kbd docutils literal notranslate">k</kbd></kbd> kill line (but doesn’t put it in clipboard)</p></li> 442<li><p><kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">C</kbd>-<kbd class="kbd docutils literal notranslate">l</kbd></kbd> center window around the insertion point</p></li> 443<li><p><kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">C</kbd>-<kbd class="kbd docutils literal notranslate">b</kbd></kbd> go backward one character without deleting (usually you can 444also use the cursor key for this)</p></li> 445<li><p><kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">C</kbd>-<kbd class="kbd docutils literal notranslate">f</kbd></kbd> go forward one character without deleting (usually you can 446also use the cursor key for this)</p></li> 447<li><p><kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">C</kbd>-<kbd class="kbd docutils literal notranslate">p</kbd></kbd> go up one line (usually you can also use the cursor key for 448this)</p></li> 449<li><p><kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">C</kbd>-<kbd class="kbd docutils literal notranslate">d</kbd></kbd> delete next character</p></li> 450</ul> 451</div></blockquote> 452</li> 453</ul> 454<p>Standard keybindings (like <kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">C</kbd>-<kbd class="kbd docutils literal notranslate">c</kbd></kbd> to copy and <kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">C</kbd>-<kbd class="kbd docutils literal notranslate">v</kbd></kbd> to paste) 455may work. Keybindings are selected in the Configure IDLE dialog.</p> 456</div> 457<div class="section" id="automatic-indentation"> 458<h3>Automatic indentation<a class="headerlink" href="#automatic-indentation" title="Permalink to this headline">¶</a></h3> 459<p>After a block-opening statement, the next line is indented by 4 spaces (in the 460Python Shell window by one tab). After certain keywords (break, return etc.) 461the next line is dedented. In leading indentation, <kbd class="kbd docutils literal notranslate">Backspace</kbd> deletes up 462to 4 spaces if they are there. <kbd class="kbd docutils literal notranslate">Tab</kbd> inserts spaces (in the Python 463Shell window one tab), number depends on Indent width. Currently, tabs 464are restricted to four spaces due to Tcl/Tk limitations.</p> 465<p>See also the indent/dedent region commands on the 466<a class="reference internal" href="#format-menu"><span class="std std-ref">Format menu</span></a>.</p> 467</div> 468<div class="section" id="completions"> 469<span id="id3"></span><h3>Completions<a class="headerlink" href="#completions" title="Permalink to this headline">¶</a></h3> 470<p>Completions are supplied, when requested and available, for module 471names, attributes of classes or functions, or filenames. Each request 472method displays a completion box with existing names. (See tab 473completions below for an exception.) For any box, change the name 474being completed and the item highlighted in the box by 475typing and deleting characters; by hitting <kbd class="kbd docutils literal notranslate">Up</kbd>, <kbd class="kbd docutils literal notranslate">Down</kbd>, 476<kbd class="kbd docutils literal notranslate">PageUp</kbd>, <kbd class="kbd docutils literal notranslate">PageDown</kbd>, <kbd class="kbd docutils literal notranslate">Home</kbd>, and <kbd class="kbd docutils literal notranslate">End</kbd> keys; 477and by a single click within the box. Close the box with <kbd class="kbd docutils literal notranslate">Escape</kbd>, 478<kbd class="kbd docutils literal notranslate">Enter</kbd>, and double <kbd class="kbd docutils literal notranslate">Tab</kbd> keys or clicks outside the box. 479A double click within the box selects and closes.</p> 480<p>One way to open a box is to type a key character and wait for a 481predefined interval. This defaults to 2 seconds; customize it 482in the settings dialog. (To prevent auto popups, set the delay to a 483large number of milliseconds, such as 100000000.) For imported module 484names or class or function attributes, type ‘.’. 485For filenames in the root directory, type <a class="reference internal" href="os.html#os.sep" title="os.sep"><code class="xref py py-data docutils literal notranslate"><span class="pre">os.sep</span></code></a> or 486<a class="reference internal" href="os.html#os.altsep" title="os.altsep"><code class="xref py py-data docutils literal notranslate"><span class="pre">os.altsep</span></code></a> immediately after an opening quote. (On Windows, 487one can specify a drive first.) Move into subdirectories by typing a 488directory name and a separator.</p> 489<p>Instead of waiting, or after a box is closed, open a completion box 490immediately with Show Completions on the Edit menu. The default hot 491key is <kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">C</kbd>-<kbd class="kbd docutils literal notranslate">space</kbd></kbd>. If one types a prefix for the desired name 492before opening the box, the first match or near miss is made visible. 493The result is the same as if one enters a prefix 494after the box is displayed. Show Completions after a quote completes 495filenames in the current directory instead of a root directory.</p> 496<p>Hitting <kbd class="kbd docutils literal notranslate">Tab</kbd> after a prefix usually has the same effect as Show 497Completions. (With no prefix, it indents.) However, if there is only 498one match to the prefix, that match is immediately added to the editor 499text without opening a box.</p> 500<p>Invoking ‘Show Completions’, or hitting <kbd class="kbd docutils literal notranslate">Tab</kbd> after a prefix, 501outside of a string and without a preceding ‘.’ opens a box with 502keywords, builtin names, and available module-level names.</p> 503<p>When editing code in an editor (as oppose to Shell), increase the 504available module-level names by running your code 505and not restarting the Shell thereafter. This is especially useful 506after adding imports at the top of a file. This also increases 507possible attribute completions.</p> 508<p>Completion boxes intially exclude names beginning with ‘_’ or, for 509modules, not included in ‘__all__’. The hidden names can be accessed 510by typing ‘_’ after ‘.’, either before or after the box is opened.</p> 511</div> 512<div class="section" id="calltips"> 513<span id="id4"></span><h3>Calltips<a class="headerlink" href="#calltips" title="Permalink to this headline">¶</a></h3> 514<p>A calltip is shown automatically when one types <kbd class="kbd docutils literal notranslate">(</kbd> after the name 515of an <em>accessible</em> function. A function name expression may include 516dots and subscripts. A calltip remains until it is clicked, the cursor 517is moved out of the argument area, or <kbd class="kbd docutils literal notranslate">)</kbd> is typed. Whenever the 518cursor is in the argument part of a definition, select Edit and “Show 519Call Tip” on the menu or enter its shortcut to display a calltip.</p> 520<p>The calltip consists of the function’s signature and docstring up to 521the latter’s first blank line or the fifth non-blank line. (Some builtin 522functions lack an accessible signature.) A ‘/’ or ‘*’ in the signature 523indicates that the preceding or following arguments are passed by 524position or name (keyword) only. Details are subject to change.</p> 525<p>In Shell, the accessible functions depends on what modules have been 526imported into the user process, including those imported by Idle itself, 527and which definitions have been run, all since the last restart.</p> 528<p>For example, restart the Shell and enter <code class="docutils literal notranslate"><span class="pre">itertools.count(</span></code>. A calltip 529appears because Idle imports itertools into the user process for its own 530use. (This could change.) Enter <code class="docutils literal notranslate"><span class="pre">turtle.write(</span></code> and nothing appears. 531Idle does not itself import turtle. The menu entry and shortcut also do 532nothing. Enter <code class="docutils literal notranslate"><span class="pre">import</span> <span class="pre">turtle</span></code>. Thereafter, <code class="docutils literal notranslate"><span class="pre">turtle.write(</span></code> 533will display a calltip.</p> 534<p>In an editor, import statements have no effect until one runs the file. 535One might want to run a file after writing import statements, after 536adding function definitions, or after opening an existing file.</p> 537</div> 538<div class="section" id="code-context"> 539<span id="id5"></span><h3>Code Context<a class="headerlink" href="#code-context" title="Permalink to this headline">¶</a></h3> 540<p>Within an editor window containing Python code, code context can be toggled 541in order to show or hide a pane at the top of the window. When shown, this 542pane freezes the opening lines for block code, such as those beginning with 543<code class="docutils literal notranslate"><span class="pre">class</span></code>, <code class="docutils literal notranslate"><span class="pre">def</span></code>, or <code class="docutils literal notranslate"><span class="pre">if</span></code> keywords, that would have otherwise scrolled 544out of view. The size of the pane will be expanded and contracted as needed 545to show the all current levels of context, up to the maximum number of 546lines defined in the Configure IDLE dialog (which defaults to 15). If there 547are no current context lines and the feature is toggled on, a single blank 548line will display. Clicking on a line in the context pane will move that 549line to the top of the editor.</p> 550<p>The text and background colors for the context pane can be configured under 551the Highlights tab in the Configure IDLE dialog.</p> 552</div> 553<div class="section" id="python-shell-window"> 554<h3>Python Shell window<a class="headerlink" href="#python-shell-window" title="Permalink to this headline">¶</a></h3> 555<p>With IDLE’s Shell, one enters, edits, and recalls complete statements. 556Most consoles and terminals only work with a single physical line at a time.</p> 557<p>When one pastes code into Shell, it is not compiled and possibly executed 558until one hits <kbd class="kbd docutils literal notranslate">Return</kbd>. One may edit pasted code first. 559If one pastes more that one statement into Shell, the result will be a 560<a class="reference internal" href="exceptions.html#SyntaxError" title="SyntaxError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">SyntaxError</span></code></a> when multiple statements are compiled as if they were one.</p> 561<p>The editing features described in previous subsections work when entering 562code interactively. IDLE’s Shell window also responds to the following keys.</p> 563<ul> 564<li><p><kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">C</kbd>-<kbd class="kbd docutils literal notranslate">c</kbd></kbd> interrupts executing command</p></li> 565<li><p><kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">C</kbd>-<kbd class="kbd docutils literal notranslate">d</kbd></kbd> sends end-of-file; closes window if typed at a <code class="docutils literal notranslate"><span class="pre">>>></span></code> prompt</p></li> 566<li><p><kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">Alt</kbd>-<kbd class="kbd docutils literal notranslate">/</kbd></kbd> (Expand word) is also useful to reduce typing</p> 567<p>Command history</p> 568<ul class="simple"> 569<li><p><kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">Alt</kbd>-<kbd class="kbd docutils literal notranslate">p</kbd></kbd> retrieves previous command matching what you have typed. On 570macOS use <kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">C</kbd>-<kbd class="kbd docutils literal notranslate">p</kbd></kbd>.</p></li> 571<li><p><kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">Alt</kbd>-<kbd class="kbd docutils literal notranslate">n</kbd></kbd> retrieves next. On macOS use <kbd class="kbd docutils literal notranslate"><kbd class="kbd docutils literal notranslate">C</kbd>-<kbd class="kbd docutils literal notranslate">n</kbd></kbd>.</p></li> 572<li><p><kbd class="kbd docutils literal notranslate">Return</kbd> while on any previous command retrieves that command</p></li> 573</ul> 574</li> 575</ul> 576</div> 577<div class="section" id="text-colors"> 578<h3>Text colors<a class="headerlink" href="#text-colors" title="Permalink to this headline">¶</a></h3> 579<p>Idle defaults to black on white text, but colors text with special meanings. 580For the shell, these are shell output, shell error, user output, and 581user error. For Python code, at the shell prompt or in an editor, these are 582keywords, builtin class and function names, names following <code class="docutils literal notranslate"><span class="pre">class</span></code> and 583<code class="docutils literal notranslate"><span class="pre">def</span></code>, strings, and comments. For any text window, these are the cursor (when 584present), found text (when possible), and selected text.</p> 585<p>Text coloring is done in the background, so uncolorized text is occasionally 586visible. To change the color scheme, use the Configure IDLE dialog 587Highlighting tab. The marking of debugger breakpoint lines in the editor and 588text in popups and dialogs is not user-configurable.</p> 589</div> 590</div> 591<div class="section" id="startup-and-code-execution"> 592<h2>Startup and code execution<a class="headerlink" href="#startup-and-code-execution" title="Permalink to this headline">¶</a></h2> 593<p>Upon startup with the <code class="docutils literal notranslate"><span class="pre">-s</span></code> option, IDLE will execute the file referenced by 594the environment variables <span class="target" id="index-5"></span><code class="xref std std-envvar docutils literal notranslate"><span class="pre">IDLESTARTUP</span></code> or <span class="target" id="index-6"></span><a class="reference internal" href="../using/cmdline.html#envvar-PYTHONSTARTUP"><code class="xref std std-envvar docutils literal notranslate"><span class="pre">PYTHONSTARTUP</span></code></a>. 595IDLE first checks for <code class="docutils literal notranslate"><span class="pre">IDLESTARTUP</span></code>; if <code class="docutils literal notranslate"><span class="pre">IDLESTARTUP</span></code> is present the file 596referenced is run. If <code class="docutils literal notranslate"><span class="pre">IDLESTARTUP</span></code> is not present, IDLE checks for 597<code class="docutils literal notranslate"><span class="pre">PYTHONSTARTUP</span></code>. Files referenced by these environment variables are 598convenient places to store functions that are used frequently from the IDLE 599shell, or for executing import statements to import common modules.</p> 600<p>In addition, <code class="docutils literal notranslate"><span class="pre">Tk</span></code> also loads a startup file if it is present. Note that the 601Tk file is loaded unconditionally. This additional file is <code class="docutils literal notranslate"><span class="pre">.Idle.py</span></code> and is 602looked for in the user’s home directory. Statements in this file will be 603executed in the Tk namespace, so this file is not useful for importing 604functions to be used from IDLE’s Python shell.</p> 605<div class="section" id="command-line-usage"> 606<h3>Command line usage<a class="headerlink" href="#command-line-usage" title="Permalink to this headline">¶</a></h3> 607<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>idle.py [-c command] [-d] [-e] [-h] [-i] [-r file] [-s] [-t title] [-] [arg] ... 608 609-c command run command in the shell window 610-d enable debugger and open shell window 611-e open editor window 612-h print help message with legal combinations and exit 613-i open shell window 614-r file run file in shell window 615-s run $IDLESTARTUP or $PYTHONSTARTUP first, in shell window 616-t title set title of shell window 617- run stdin in shell (- must be last option before args) 618</pre></div> 619</div> 620<p>If there are arguments:</p> 621<ul class="simple"> 622<li><p>If <code class="docutils literal notranslate"><span class="pre">-</span></code>, <code class="docutils literal notranslate"><span class="pre">-c</span></code>, or <code class="docutils literal notranslate"><span class="pre">r</span></code> is used, all arguments are placed in 623<code class="docutils literal notranslate"><span class="pre">sys.argv[1:...]</span></code> and <code class="docutils literal notranslate"><span class="pre">sys.argv[0]</span></code> is set to <code class="docutils literal notranslate"><span class="pre">''</span></code>, <code class="docutils literal notranslate"><span class="pre">'-c'</span></code>, 624or <code class="docutils literal notranslate"><span class="pre">'-r'</span></code>. No editor window is opened, even if that is the default 625set in the Options dialog.</p></li> 626<li><p>Otherwise, arguments are files opened for editing and 627<code class="docutils literal notranslate"><span class="pre">sys.argv</span></code> reflects the arguments passed to IDLE itself.</p></li> 628</ul> 629</div> 630<div class="section" id="startup-failure"> 631<h3>Startup failure<a class="headerlink" href="#startup-failure" title="Permalink to this headline">¶</a></h3> 632<p>IDLE uses a socket to communicate between the IDLE GUI process and the user 633code execution process. A connection must be established whenever the Shell 634starts or restarts. (The latter is indicated by a divider line that says 635‘RESTART’). If the user process fails to connect to the GUI process, it 636displays a <code class="docutils literal notranslate"><span class="pre">Tk</span></code> error box with a ‘cannot connect’ message that directs the 637user here. It then exits.</p> 638<p>A common cause of failure is a user-written file with the same name as a 639standard library module, such as <em>random.py</em> and <em>tkinter.py</em>. When such a 640file is located in the same directory as a file that is about to be run, 641IDLE cannot import the stdlib file. The current fix is to rename the 642user file.</p> 643<p>Though less common than in the past, an antivirus or firewall program may 644stop the connection. If the program cannot be taught to allow the 645connection, then it must be turned off for IDLE to work. It is safe to 646allow this internal connection because no data is visible on external 647ports. A similar problem is a network mis-configuration that blocks 648connections.</p> 649<p>Python installation issues occasionally stop IDLE: multiple versions can 650clash, or a single installation might need admin access. If one undo the 651clash, or cannot or does not want to run as admin, it might be easiest to 652completely remove Python and start over.</p> 653<p>A zombie pythonw.exe process could be a problem. On Windows, use Task 654Manager to check for one and stop it if there is. Sometimes a restart 655initiated by a program crash or Keyboard Interrupt (control-C) may fail 656to connect. Dismissing the error box or using Restart Shell on the Shell 657menu may fix a temporary problem.</p> 658<p>When IDLE first starts, it attempts to read user configuration files in 659<code class="docutils literal notranslate"><span class="pre">~/.idlerc/</span></code> (~ is one’s home directory). If there is a problem, an error 660message should be displayed. Leaving aside random disk glitches, this can 661be prevented by never editing the files by hand. Instead, use the 662configuration dialog, under Options. Once there is an error in a user 663configuration file, the best solution may be to delete it and start over 664with the settings dialog.</p> 665<p>If IDLE quits with no message, and it was not started from a console, try 666starting it from a console or terminal (<code class="docutils literal notranslate"><span class="pre">python</span> <span class="pre">-m</span> <span class="pre">idlelib</span></code>) and see if 667this results in an error message.</p> 668</div> 669<div class="section" id="running-user-code"> 670<h3>Running user code<a class="headerlink" href="#running-user-code" title="Permalink to this headline">¶</a></h3> 671<p>With rare exceptions, the result of executing Python code with IDLE is 672intended to be the same as executing the same code by the default method, 673directly with Python in a text-mode system console or terminal window. 674However, the different interface and operation occasionally affect 675visible results. For instance, <code class="docutils literal notranslate"><span class="pre">sys.modules</span></code> starts with more entries, 676and <code class="docutils literal notranslate"><span class="pre">threading.activeCount()</span></code> returns 2 instead of 1.</p> 677<p>By default, IDLE runs user code in a separate OS process rather than in 678the user interface process that runs the shell and editor. In the execution 679process, it replaces <code class="docutils literal notranslate"><span class="pre">sys.stdin</span></code>, <code class="docutils literal notranslate"><span class="pre">sys.stdout</span></code>, and <code class="docutils literal notranslate"><span class="pre">sys.stderr</span></code> 680with objects that get input from and send output to the Shell window. 681The original values stored in <code class="docutils literal notranslate"><span class="pre">sys.__stdin__</span></code>, <code class="docutils literal notranslate"><span class="pre">sys.__stdout__</span></code>, and 682<code class="docutils literal notranslate"><span class="pre">sys.__stderr__</span></code> are not touched, but may be <code class="docutils literal notranslate"><span class="pre">None</span></code>.</p> 683<p>When Shell has the focus, it controls the keyboard and screen. This is 684normally transparent, but functions that directly access the keyboard 685and screen will not work. These include system-specific functions that 686determine whether a key has been pressed and if so, which.</p> 687<p>IDLE’s standard stream replacements are not inherited by subprocesses 688created in the execution process, whether directly by user code or by modules 689such as multiprocessing. If such subprocess use <code class="docutils literal notranslate"><span class="pre">input</span></code> from sys.stdin 690or <code class="docutils literal notranslate"><span class="pre">print</span></code> or <code class="docutils literal notranslate"><span class="pre">write</span></code> to sys.stdout or sys.stderr, 691IDLE should be started in a command line window. The secondary subprocess 692will then be attached to that window for input and output.</p> 693<p>The IDLE code running in the execution process adds frames to the call stack 694that would not be there otherwise. IDLE wraps <code class="docutils literal notranslate"><span class="pre">sys.getrecursionlimit</span></code> and 695<code class="docutils literal notranslate"><span class="pre">sys.setrecursionlimit</span></code> to reduce the effect of the additional stack frames.</p> 696<p>If <code class="docutils literal notranslate"><span class="pre">sys</span></code> is reset by user code, such as with <code class="docutils literal notranslate"><span class="pre">importlib.reload(sys)</span></code>, 697IDLE’s changes are lost and input from the keyboard and output to the screen 698will not work correctly.</p> 699<p>When user code raises SystemExit either directly or by calling sys.exit, IDLE 700returns to a Shell prompt instead of exiting.</p> 701</div> 702<div class="section" id="user-output-in-shell"> 703<h3>User output in Shell<a class="headerlink" href="#user-output-in-shell" title="Permalink to this headline">¶</a></h3> 704<p>When a program outputs text, the result is determined by the 705corresponding output device. When IDLE executes user code, <code class="docutils literal notranslate"><span class="pre">sys.stdout</span></code> 706and <code class="docutils literal notranslate"><span class="pre">sys.stderr</span></code> are connected to the display area of IDLE’s Shell. Some of 707its features are inherited from the underlying Tk Text widget. Others 708are programmed additions. Where it matters, Shell is designed for development 709rather than production runs.</p> 710<p>For instance, Shell never throws away output. A program that sends unlimited 711output to Shell will eventually fill memory, resulting in a memory error. 712In contrast, some system text windows only keep the last n lines of output. 713A Windows console, for instance, keeps a user-settable 1 to 9999 lines, 714with 300 the default.</p> 715<p>A Tk Text widget, and hence IDLE’s Shell, displays characters (codepoints) in 716the BMP (Basic Multilingual Plane) subset of Unicode. Which characters are 717displayed with a proper glyph and which with a replacement box depends on the 718operating system and installed fonts. Tab characters cause the following text 719to begin after the next tab stop. (They occur every 8 ‘characters’). Newline 720characters cause following text to appear on a new line. Other control 721characters are ignored or displayed as a space, box, or something else, 722depending on the operating system and font. (Moving the text cursor through 723such output with arrow keys may exhibit some surprising spacing behavior.)</p> 724<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">s</span> <span class="o">=</span> <span class="s1">'a</span><span class="se">\t</span><span class="s1">b</span><span class="se">\a</span><span class="s1"><</span><span class="se">\x02</span><span class="s1">><</span><span class="se">\r</span><span class="s1">></span><span class="se">\b</span><span class="s1">c</span><span class="se">\n</span><span class="s1">d'</span> <span class="c1"># Enter 22 chars.</span> 725<span class="gp">>>> </span><span class="nb">len</span><span class="p">(</span><span class="n">s</span><span class="p">)</span> 726<span class="go">14</span> 727<span class="gp">>>> </span><span class="n">s</span> <span class="c1"># Display repr(s)</span> 728<span class="go">'a\tb\x07<\x02><\r>\x08c\nd'</span> 729<span class="gp">>>> </span><span class="nb">print</span><span class="p">(</span><span class="n">s</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="s1">''</span><span class="p">)</span> <span class="c1"># Display s as is.</span> 730<span class="go"># Result varies by OS and font. Try it.</span> 731</pre></div> 732</div> 733<p>The <code class="docutils literal notranslate"><span class="pre">repr</span></code> function is used for interactive echo of expression 734values. It returns an altered version of the input string in which 735control codes, some BMP codepoints, and all non-BMP codepoints are 736replaced with escape codes. As demonstrated above, it allows one to 737identify the characters in a string, regardless of how they are displayed.</p> 738<p>Normal and error output are generally kept separate (on separate lines) 739from code input and each other. They each get different highlight colors.</p> 740<p>For SyntaxError tracebacks, the normal ‘^’ marking where the error was 741detected is replaced by coloring the text with an error highlight. 742When code run from a file causes other exceptions, one may right click 743on a traceback line to jump to the corresponding line in an IDLE editor. 744The file will be opened if necessary.</p> 745<p>Shell has a special facility for squeezing output lines down to a 746‘Squeezed text’ label. This is done automatically 747for output over N lines (N = 50 by default). 748N can be changed in the PyShell section of the General 749page of the Settings dialog. Output with fewer lines can be squeezed by 750right clicking on the output. This can be useful lines long enough to slow 751down scrolling.</p> 752<p>Squeezed output is expanded in place by double-clicking the label. 753It can also be sent to the clipboard or a separate view window by 754right-clicking the label.</p> 755</div> 756<div class="section" id="developing-tkinter-applications"> 757<h3>Developing tkinter applications<a class="headerlink" href="#developing-tkinter-applications" title="Permalink to this headline">¶</a></h3> 758<p>IDLE is intentionally different from standard Python in order to 759facilitate development of tkinter programs. Enter <code class="docutils literal notranslate"><span class="pre">import</span> <span class="pre">tkinter</span> <span class="pre">as</span> <span class="pre">tk;</span> 760<span class="pre">root</span> <span class="pre">=</span> <span class="pre">tk.Tk()</span></code> in standard Python and nothing appears. Enter the same 761in IDLE and a tk window appears. In standard Python, one must also enter 762<code class="docutils literal notranslate"><span class="pre">root.update()</span></code> to see the window. IDLE does the equivalent in the 763background, about 20 times a second, which is about every 50 milliseconds. 764Next enter <code class="docutils literal notranslate"><span class="pre">b</span> <span class="pre">=</span> <span class="pre">tk.Button(root,</span> <span class="pre">text='button');</span> <span class="pre">b.pack()</span></code>. Again, 765nothing visibly changes in standard Python until one enters <code class="docutils literal notranslate"><span class="pre">root.update()</span></code>.</p> 766<p>Most tkinter programs run <code class="docutils literal notranslate"><span class="pre">root.mainloop()</span></code>, which usually does not 767return until the tk app is destroyed. If the program is run with 768<code class="docutils literal notranslate"><span class="pre">python</span> <span class="pre">-i</span></code> or from an IDLE editor, a <code class="docutils literal notranslate"><span class="pre">>>></span></code> shell prompt does not 769appear until <code class="docutils literal notranslate"><span class="pre">mainloop()</span></code> returns, at which time there is nothing left 770to interact with.</p> 771<p>When running a tkinter program from an IDLE editor, one can comment out 772the mainloop call. One then gets a shell prompt immediately and can 773interact with the live application. One just has to remember to 774re-enable the mainloop call when running in standard Python.</p> 775</div> 776<div class="section" id="running-without-a-subprocess"> 777<h3>Running without a subprocess<a class="headerlink" href="#running-without-a-subprocess" title="Permalink to this headline">¶</a></h3> 778<p>By default, IDLE executes user code in a separate subprocess via a socket, 779which uses the internal loopback interface. This connection is not 780externally visible and no data is sent to or received from the Internet. 781If firewall software complains anyway, you can ignore it.</p> 782<p>If the attempt to make the socket connection fails, Idle will notify you. 783Such failures are sometimes transient, but if persistent, the problem 784may be either a firewall blocking the connection or misconfiguration of 785a particular system. Until the problem is fixed, one can run Idle with 786the -n command line switch.</p> 787<p>If IDLE is started with the -n command line switch it will run in a 788single process and will not create the subprocess which runs the RPC 789Python execution server. This can be useful if Python cannot create 790the subprocess or the RPC socket interface on your platform. However, 791in this mode user code is not isolated from IDLE itself. Also, the 792environment is not restarted when Run/Run Module (F5) is selected. If 793your code has been modified, you must reload() the affected modules and 794re-import any specific items (e.g. from foo import baz) if the changes 795are to take effect. For these reasons, it is preferable to run IDLE 796with the default subprocess if at all possible.</p> 797<div class="deprecated"> 798<p><span class="versionmodified deprecated">Deprecated since version 3.4.</span></p> 799</div> 800</div> 801</div> 802<div class="section" id="help-and-preferences"> 803<h2>Help and preferences<a class="headerlink" href="#help-and-preferences" title="Permalink to this headline">¶</a></h2> 804<div class="section" id="help-sources"> 805<span id="id6"></span><h3>Help sources<a class="headerlink" href="#help-sources" title="Permalink to this headline">¶</a></h3> 806<p>Help menu entry “IDLE Help” displays a formatted html version of the 807IDLE chapter of the Library Reference. The result, in a read-only 808tkinter text window, is close to what one sees in a web browser. 809Navigate through the text with a mousewheel, 810the scrollbar, or up and down arrow keys held down. 811Or click the TOC (Table of Contents) button and select a section 812header in the opened box.</p> 813<p>Help menu entry “Python Docs” opens the extensive sources of help, 814including tutorials, available at <code class="docutils literal notranslate"><span class="pre">docs.python.org/x.y</span></code>, where ‘x.y’ 815is the currently running Python version. If your system 816has an off-line copy of the docs (this may be an installation option), 817that will be opened instead.</p> 818<p>Selected URLs can be added or removed from the help menu at any time using the 819General tab of the Configure IDLE dialog.</p> 820</div> 821<div class="section" id="setting-preferences"> 822<span id="preferences"></span><h3>Setting preferences<a class="headerlink" href="#setting-preferences" title="Permalink to this headline">¶</a></h3> 823<p>The font preferences, highlighting, keys, and general preferences can be 824changed via Configure IDLE on the Option menu. 825Non-default user settings are saved in a <code class="docutils literal notranslate"><span class="pre">.idlerc</span></code> directory in the user’s 826home directory. Problems caused by bad user configuration files are solved 827by editing or deleting one or more of the files in <code class="docutils literal notranslate"><span class="pre">.idlerc</span></code>.</p> 828<p>On the Font tab, see the text sample for the effect of font face and size 829on multiple characters in multiple languages. Edit the sample to add 830other characters of personal interest. Use the sample to select 831monospaced fonts. If particular characters have problems in Shell or an 832editor, add them to the top of the sample and try changing first size 833and then font.</p> 834<p>On the Highlights and Keys tab, select a built-in or custom color theme 835and key set. To use a newer built-in color theme or key set with older 836IDLEs, save it as a new custom theme or key set and it well be accessible 837to older IDLEs.</p> 838</div> 839<div class="section" id="idle-on-macos"> 840<h3>IDLE on macOS<a class="headerlink" href="#idle-on-macos" title="Permalink to this headline">¶</a></h3> 841<p>Under System Preferences: Dock, one can set “Prefer tabs when opening 842documents” to “Always”. This setting is not compatible with the tk/tkinter 843GUI framework used by IDLE, and it breaks a few IDLE features.</p> 844</div> 845<div class="section" id="extensions"> 846<h3>Extensions<a class="headerlink" href="#extensions" title="Permalink to this headline">¶</a></h3> 847<p>IDLE contains an extension facility. Preferences for extensions can be 848changed with the Extensions tab of the preferences dialog. See the 849beginning of config-extensions.def in the idlelib directory for further 850information. The only current default extension is zzdummy, an example 851also used for testing.</p> 852</div> 853</div> 854</div> 855 856 857 <div class="clearer"></div> 858 </div> 859 </div> 860 </div> 861 <div class="sphinxsidebar" role="navigation" aria-label="main navigation"> 862 <div class="sphinxsidebarwrapper"> 863 <h3><a href="../contents.html">Table of Contents</a></h3> 864 <ul> 865<li><a class="reference internal" href="#">IDLE</a><ul> 866<li><a class="reference internal" href="#menus">Menus</a><ul> 867<li><a class="reference internal" href="#file-menu-shell-and-editor">File menu (Shell and Editor)</a></li> 868<li><a class="reference internal" href="#edit-menu-shell-and-editor">Edit menu (Shell and Editor)</a></li> 869<li><a class="reference internal" href="#format-menu-editor-window-only">Format menu (Editor window only)</a></li> 870<li><a class="reference internal" href="#run-menu-editor-window-only">Run menu (Editor window only)</a></li> 871<li><a class="reference internal" href="#shell-menu-shell-window-only">Shell menu (Shell window only)</a></li> 872<li><a class="reference internal" href="#debug-menu-shell-window-only">Debug menu (Shell window only)</a></li> 873<li><a class="reference internal" href="#options-menu-shell-and-editor">Options menu (Shell and Editor)</a></li> 874<li><a class="reference internal" href="#window-menu-shell-and-editor">Window menu (Shell and Editor)</a></li> 875<li><a class="reference internal" href="#help-menu-shell-and-editor">Help menu (Shell and Editor)</a></li> 876<li><a class="reference internal" href="#context-menus">Context Menus</a></li> 877</ul> 878</li> 879<li><a class="reference internal" href="#editing-and-navigation">Editing and navigation</a><ul> 880<li><a class="reference internal" href="#editor-windows">Editor windows</a></li> 881<li><a class="reference internal" href="#key-bindings">Key bindings</a></li> 882<li><a class="reference internal" href="#automatic-indentation">Automatic indentation</a></li> 883<li><a class="reference internal" href="#completions">Completions</a></li> 884<li><a class="reference internal" href="#calltips">Calltips</a></li> 885<li><a class="reference internal" href="#code-context">Code Context</a></li> 886<li><a class="reference internal" href="#python-shell-window">Python Shell window</a></li> 887<li><a class="reference internal" href="#text-colors">Text colors</a></li> 888</ul> 889</li> 890<li><a class="reference internal" href="#startup-and-code-execution">Startup and code execution</a><ul> 891<li><a class="reference internal" href="#command-line-usage">Command line usage</a></li> 892<li><a class="reference internal" href="#startup-failure">Startup failure</a></li> 893<li><a class="reference internal" href="#running-user-code">Running user code</a></li> 894<li><a class="reference internal" href="#user-output-in-shell">User output in Shell</a></li> 895<li><a class="reference internal" href="#developing-tkinter-applications">Developing tkinter applications</a></li> 896<li><a class="reference internal" href="#running-without-a-subprocess">Running without a subprocess</a></li> 897</ul> 898</li> 899<li><a class="reference internal" href="#help-and-preferences">Help and preferences</a><ul> 900<li><a class="reference internal" href="#help-sources">Help sources</a></li> 901<li><a class="reference internal" href="#setting-preferences">Setting preferences</a></li> 902<li><a class="reference internal" href="#idle-on-macos">IDLE on macOS</a></li> 903<li><a class="reference internal" href="#extensions">Extensions</a></li> 904</ul> 905</li> 906</ul> 907</li> 908</ul> 909 910 <h4>Previous topic</h4> 911 <p class="topless"><a href="tkinter.tix.html" 912 title="previous chapter"><code class="xref py py-mod docutils literal notranslate"><span class="pre">tkinter.tix</span></code> — Extension widgets for Tk</a></p> 913 <h4>Next topic</h4> 914 <p class="topless"><a href="othergui.html" 915 title="next chapter">Other Graphical User Interface Packages</a></p> 916 <div role="note" aria-label="source link"> 917 <h3>This Page</h3> 918 <ul class="this-page-menu"> 919 <li><a href="../bugs.html">Report a Bug</a></li> 920 <li> 921 <a href="https://github.com/python/cpython/blob/master/Doc/library/idle.rst" 922 rel="nofollow">Show Source 923 </a> 924 </li> 925 </ul> 926 </div> 927 </div> 928 </div> 929 <div class="clearer"></div> 930 </div> 931 <div class="related" role="navigation" aria-label="related navigation"> 932 <h3>Navigation</h3> 933 <ul> 934 <li class="right" style="margin-right: 10px"> 935 <a href="../genindex.html" title="General Index" 936 >index</a></li> 937 <li class="right" > 938 <a href="../py-modindex.html" title="Python Module Index" 939 >modules</a> |</li> 940 <li class="right" > 941 <a href="othergui.html" title="Other Graphical User Interface Packages" 942 >next</a> |</li> 943 <li class="right" > 944 <a href="tkinter.tix.html" title="tkinter.tix — Extension widgets for Tk" 945 >previous</a> |</li> 946 947 <li><img src="../_static/py.png" alt="" 948 style="vertical-align: middle; margin-top: -1px"/></li> 949 <li><a href="https://www.python.org/">Python</a> »</li> 950 951 952 <li> 953 <a href="../index.html">3.10.0a1 Documentation</a> » 954 </li> 955 956 <li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> »</li> 957 <li class="nav-item nav-item-2"><a href="tk.html" >Graphical User Interfaces with Tk</a> »</li> 958 <li class="nav-item nav-item-this"><a href="">IDLE</a></li> 959 <li class="right"> 960 961 962 <div class="inline-search" style="display: none" role="search"> 963 <form class="inline-search" action="../search.html" method="get"> 964 <input placeholder="Quick search" type="text" name="q" /> 965 <input type="submit" value="Go" /> 966 <input type="hidden" name="check_keywords" value="yes" /> 967 <input type="hidden" name="area" value="default" /> 968 </form> 969 </div> 970 <script type="text/javascript">$('.inline-search').show(0);</script> 971 | 972 </li> 973 974 </ul> 975 </div> 976 <div class="footer"> 977 © <a href="../copyright.html">Copyright</a> 2001-2020, Python Software Foundation. 978 <br /> 979 980 The Python Software Foundation is a non-profit corporation. 981<a href="https://www.python.org/psf/donations/">Please donate.</a> 982<br /> 983 <br /> 984 985 Last updated on Oct 20, 2020. 986 <a href="https://docs.python.org/3/bugs.html">Found a bug</a>? 987 <br /> 988 989 Created using <a href="https://www.sphinx-doc.org/">Sphinx</a> 3.2.1. 990 </div> 991 992 </body> 993</html> 994
