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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
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<div class="section" id="idle">
<span id="id1"></span><h1>IDLE<a class="headerlink" href="#idle" title="Permalink to this headline">¶</a></h1>
<p><strong>Source code:</strong> <a class="reference external" href="https://github.com/python/cpython/tree/master/Lib/idlelib/">Lib/idlelib/</a></p>
<hr class="docutils" id="index-0" />
<p>IDLE is Python’s Integrated Development and Learning Environment.</p>
<p>IDLE has the following features:</p>
<ul class="simple">
<li>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</li>
<li>cross-platform: works mostly the same on Windows, Unix, and macOS</li>
<li>Python shell window (interactive interpreter) with colorizing
of code input, output, and error messages</li>
<li>multi-window text editor with multiple undo, Python colorizing,
smart indent, call tips, auto completion, and other features</li>
<li>search within any window, replace within editor windows, and search
through multiple files (grep)</li>
<li>debugger with persistent breakpoints, stepping, and viewing
of global and local namespaces</li>
<li>configuration, browsers, and other dialogs</li>
</ul>
<div class="section" id="menus">
<h2>Menus<a class="headerlink" href="#menus" title="Permalink to this headline">¶</a></h2>
<p>IDLE has two main window types, the Shell window and the Editor window. It is
possible to have multiple editor windows simultaneously. On Windows and
Linux, each has its own top menu. Each menu documented below indicates
which window type it is associated with.</p>
<p>Output windows, such as used for Edit => Find in Files, are a subtype of editor
window. They currently have the same top menu but a different
default title and context menu.</p>
<p>On macOS, there is one application menu. It dynamically changes according
to the window currently selected. It has an IDLE menu, and some entries
described below are moved around to conform to Apple guidelines.</p>
<div class="section" id="file-menu-shell-and-editor">
<h3>File menu (Shell and Editor)<a class="headerlink" href="#file-menu-shell-and-editor" title="Permalink to this headline">¶</a></h3>
<dl class="docutils">
<dt>New File</dt><dd>Create a new file editing window.</dd>
<dt>Open…</dt><dd>Open an existing file with an Open dialog.</dd>
<dt>Recent Files</dt><dd>Open a list of recent files. Click one to open it.</dd>
<dt>Open Module…</dt><dd>Open an existing module (searches sys.path).</dd>
</dl>
<dl class="docutils" id="index-1">
<dt>Class Browser</dt><dd>Show functions, classes, and methods in the current Editor file in a
tree structure. In the shell, open a module first.</dd>
<dt>Path Browser</dt><dd>Show sys.path directories, modules, functions, classes and methods in a
tree structure.</dd>
<dt>Save</dt><dd>Save the current window to the associated file, if there is one. Windows
that have been changed since being opened or last saved have a * before
and after the window title. If there is no associated file,
do Save As instead.</dd>
<dt>Save As…</dt><dd>Save the current window with a Save As dialog. The file saved becomes the
new associated file for the window.</dd>
<dt>Save Copy As…</dt><dd>Save the current window to different file without changing the associated
file.</dd>
<dt>Print Window</dt><dd>Print the current window to the default printer.</dd>
<dt>Close</dt><dd>Close the current window (ask to save if unsaved).</dd>
<dt>Exit</dt><dd>Close all windows and quit IDLE (ask to save unsaved windows).</dd>
</dl>
</div>
<div class="section" id="edit-menu-shell-and-editor">
<h3>Edit menu (Shell and Editor)<a class="headerlink" href="#edit-menu-shell-and-editor" title="Permalink to this headline">¶</a></h3>
<dl class="docutils">
<dt>Undo</dt><dd>Undo the last change to the current window. A maximum of 1000 changes may
be undone.</dd>
<dt>Redo</dt><dd>Redo the last undone change to the current window.</dd>
<dt>Cut</dt><dd>Copy selection into the system-wide clipboard; then delete the selection.</dd>
<dt>Copy</dt><dd>Copy selection into the system-wide clipboard.</dd>
<dt>Paste</dt><dd>Insert contents of the system-wide clipboard into the current window.</dd>
</dl>
<p>The clipboard functions are also available in context menus.</p>
<dl class="docutils">
<dt>Select All</dt><dd>Select the entire contents of the current window.</dd>
<dt>Find…</dt><dd>Open a search dialog with many options</dd>
<dt>Find Again</dt><dd>Repeat the last search, if there is one.</dd>
<dt>Find Selection</dt><dd>Search for the currently selected string, if there is one.</dd>
<dt>Find in Files…</dt><dd>Open a file search dialog. Put results in a new output window.</dd>
<dt>Replace…</dt><dd>Open a search-and-replace dialog.</dd>
<dt>Go to Line</dt><dd>Move cursor to the line number requested and make that line visible.</dd>
<dt>Show Completions</dt><dd>Open a scrollable list allowing selection of keywords and attributes. See
<a class="reference internal" href="#completions"><span class="std std-ref">Completions</span></a> in the Editing and navigation section below.</dd>
<dt>Expand Word</dt><dd>Expand a prefix you have typed to match a full word in the same window;
repeat to get a different expansion.</dd>
<dt>Show call tip</dt><dd>After an unclosed parenthesis for a function, open a small window with
function parameter hints. See <a class="reference internal" href="#calltips"><span class="std std-ref">Calltips</span></a> in the
Editing and navigation section below.</dd>
<dt>Show surrounding parens</dt><dd>Highlight the surrounding parenthesis.</dd>
</dl>
</div>
<div class="section" id="format-menu-editor-window-only">
<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>
<dl class="docutils">
<dt>Indent Region</dt><dd>Shift selected lines right by the indent width (default 4 spaces).</dd>
<dt>Dedent Region</dt><dd>Shift selected lines left by the indent width (default 4 spaces).</dd>
<dt>Comment Out Region</dt><dd>Insert ## in front of selected lines.</dd>
<dt>Uncomment Region</dt><dd>Remove leading # or ## from selected lines.</dd>
<dt>Tabify Region</dt><dd>Turn <em>leading</em> stretches of spaces into tabs. (Note: We recommend using
4 space blocks to indent Python code.)</dd>
<dt>Untabify Region</dt><dd>Turn <em>all</em> tabs into the correct number of spaces.</dd>
<dt>Toggle Tabs</dt><dd>Open a dialog to switch between indenting with spaces and tabs.</dd>
<dt>New Indent Width</dt><dd>Open a dialog to change indent width. The accepted default by the Python
community is 4 spaces.</dd>
<dt>Format Paragraph</dt><dd>Reformat the current blank-line-delimited paragraph in comment block or
multiline string or selected line in a string. All lines in the
paragraph will be formatted to less than N columns, where N defaults to 72.</dd>
<dt>Strip trailing whitespace</dt><dd>Remove trailing space and other whitespace characters after the last
non-whitespace character of a line by applying str.rstrip to each line,
including lines within multiline strings.</dd>
</dl>
</div>
<div class="section" id="run-menu-editor-window-only">
<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>
<dl class="docutils" id="python-shell">
<dt>Python Shell</dt><dd>Open or wake up the Python Shell window.</dd>
</dl>
<dl class="docutils" id="check-module">
<dt>Check Module</dt><dd>Check the syntax of the module currently open in the Editor window. If the
module has not been saved IDLE will either prompt the user to save or
autosave, as selected in the General tab of the Idle Settings dialog. If
there is a syntax error, the approximate location is indicated in the
Editor window.</dd>
</dl>
<dl class="docutils" id="run-module">
<dt>Run Module</dt><dd>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
environment, then execute the module. Output is displayed in the Shell
window. 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>.
When execution is complete, the Shell retains focus and displays a prompt.
At this point, one may interactively explore the result of execution.
This 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
line.</dd>
</dl>
<dl class="docutils" id="run-custom">
<dt>Run… Customized</dt><dd>Same as <a class="reference internal" href="#run-module"><span class="std std-ref">Run Module</span></a>, but run the module with customized
settings. <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
on a command line. The module can be run in the Shell without restarting.</dd>
</dl>
</div>
<div class="section" id="shell-menu-shell-window-only">
<h3>Shell menu (Shell window only)<a class="headerlink" href="#shell-menu-shell-window-only" title="Permalink to this headline">¶</a></h3>
<dl class="docutils">
<dt>View Last Restart</dt><dd>Scroll the shell window to the last Shell restart.</dd>
<dt>Restart Shell</dt><dd>Restart the shell to clean the environment.</dd>
<dt>Previous History</dt><dd>Cycle through earlier commands in history which match the current entry.</dd>
<dt>Next History</dt><dd>Cycle through later commands in history which match the current entry.</dd>
<dt>Interrupt Execution</dt><dd>Stop a running program.</dd>
</dl>
</div>
<div class="section" id="debug-menu-shell-window-only">
<h3>Debug menu (Shell window only)<a class="headerlink" href="#debug-menu-shell-window-only" title="Permalink to this headline">¶</a></h3>
<dl class="docutils">
<dt>Go to File/Line</dt><dd>Look on the current line. with the cursor, and the line above for a filename
and line number. If found, open the file if not already open, and show the
line. Use this to view source lines referenced in an exception traceback
and lines found by Find in Files. Also available in the context menu of
the Shell window and Output windows.</dd>
</dl>
<dl class="docutils" id="index-3">
<dt>Debugger (toggle)</dt><dd>When activated, code entered in the Shell or run from an Editor will run
under the debugger. In the Editor, breakpoints can be set with the context
menu. This feature is still incomplete and somewhat experimental.</dd>
<dt>Stack Viewer</dt><dd>Show the stack traceback of the last exception in a tree widget, with
access to locals and globals.</dd>
<dt>Auto-open Stack Viewer</dt><dd>Toggle automatically opening the stack viewer on an unhandled exception.</dd>
</dl>
</div>
<div class="section" id="options-menu-shell-and-editor">
<h3>Options menu (Shell and Editor)<a class="headerlink" href="#options-menu-shell-and-editor" title="Permalink to this headline">¶</a></h3>
<dl class="docutils">
<dt>Configure IDLE</dt><dd>Open a configuration dialog and change preferences for the following:
fonts, indentation, keybindings, text color themes, startup windows and
size, additional help sources, and extensions. On macOS, open the
configuration dialog by selecting Preferences in the application
menu. For more, see
<a class="reference internal" href="#preferences"><span class="std std-ref">Setting preferences</span></a> under Help and preferences.
Most configuration options apply to all windows or all future windows.
The option items below only apply to the active window.</dd>
<dt>Show/Hide Code Context (Editor Window only)</dt><dd>Open a pane at the top of the edit window which shows the block context
of the code which has scrolled above the top of the window. See
<a class="reference internal" href="#code-context"><span class="std std-ref">Code Context</span></a> in the Editing and Navigation section below.</dd>
<dt>Line Numbers (Editor Window only)</dt><dd>Open a column to the left of the edit window which shows the linenumber
of each line of text. The default is off unless configured on
(see <a class="reference internal" href="#preferences"><span class="std std-ref">Setting preferences</span></a>).</dd>
<dt>Zoom/Restore Height</dt><dd>Toggles the window between normal size and maximum height. The initial size
defaults to 40 lines by 80 chars unless changed on the General tab of the
Configure IDLE dialog. The maximum height for a screen is determined by
momentarily maximizing a window the first time one is zoomed on the screen.
Changing screen settings may invalidate the saved height. This toogle has
no effect when a window is maximized.</dd>
</dl>
</div>
<div class="section" id="window-menu-shell-and-editor">
<h3>Window menu (Shell and Editor)<a class="headerlink" href="#window-menu-shell-and-editor" title="Permalink to this headline">¶</a></h3>
<p>Lists the names of all open windows; select one to bring it to the foreground
(deiconifying it if necessary).</p>
</div>
<div class="section" id="help-menu-shell-and-editor">
<h3>Help menu (Shell and Editor)<a class="headerlink" href="#help-menu-shell-and-editor" title="Permalink to this headline">¶</a></h3>
<dl class="docutils">
<dt>About IDLE</dt><dd>Display version, copyright, license, credits, and more.</dd>
<dt>IDLE Help</dt><dd>Display this IDLE document, detailing the menu options, basic editing and
navigation, and other tips.</dd>
<dt>Python Docs</dt><dd>Access local Python documentation, if installed, or start a web browser
and open docs.python.org showing the latest Python documentation.</dd>
<dt>Turtle Demo</dt><dd>Run the turtledemo module with example Python code and turtle drawings.</dd>
</dl>
<p>Additional help sources may be added here with the Configure IDLE dialog under
the General tab. See the <a class="reference internal" href="#help-sources"><span class="std std-ref">Help sources</span></a> subsection below
for more on Help menu choices.</p>
</div>
<div class="section" id="context-menus">
<span id="index-4"></span><h3>Context Menus<a class="headerlink" href="#context-menus" title="Permalink to this headline">¶</a></h3>
<p>Open a context menu by right-clicking in a window (Control-click on macOS).
Context menus have the standard clipboard functions also on the Edit menu.</p>
<dl class="docutils">
<dt>Cut</dt><dd>Copy selection into the system-wide clipboard; then delete the selection.</dd>
<dt>Copy</dt><dd>Copy selection into the system-wide clipboard.</dd>
<dt>Paste</dt><dd>Insert contents of the system-wide clipboard into the current window.</dd>
</dl>
<p>Editor windows also have breakpoint functions. Lines with a breakpoint set are
specially marked. Breakpoints only have an effect when running under the
debugger. Breakpoints for a file are saved in the user’s .idlerc directory.</p>
<dl class="docutils">
<dt>Set Breakpoint</dt><dd>Set a breakpoint on the current line.</dd>
<dt>Clear Breakpoint</dt><dd>Clear the breakpoint on that line.</dd>
</dl>
<p>Shell and Output windows also have the following.</p>
<dl class="docutils">
<dt>Go to file/line</dt><dd>Same as in Debug menu.</dd>
</dl>
<p>The Shell window also has an output squeezing facility explained in the <em>Python
Shell window</em> subsection below.</p>
<dl class="docutils">
<dt>Squeeze</dt><dd>If the cursor is over an output line, squeeze all the output between
the code above and the prompt below down to a ‘Squeezed text’ label.</dd>
</dl>
</div>
</div>
<div class="section" id="editing-and-navigation">
<span id="id2"></span><h2>Editing and navigation<a class="headerlink" href="#editing-and-navigation" title="Permalink to this headline">¶</a></h2>
<div class="section" id="editor-windows">
<h3>Editor windows<a class="headerlink" href="#editor-windows" title="Permalink to this headline">¶</a></h3>
<p>IDLE may open editor windows when it starts, depending on settings
and how you start IDLE. Thereafter, use the File menu. There can be only
one open editor window for a given file.</p>
<p>The title bar contains the name of the file, the full path, and the version
of Python and IDLE running the window. The status bar contains the line
number (‘Ln’) and column number (‘Col’). Line numbers start with 1;
column numbers with 0.</p>
<p>IDLE assumes that files with a known .py* extension contain Python code
and that other files do not. Run Python code with the Run menu.</p>
</div>
<div class="section" id="key-bindings">
<h3>Key bindings<a class="headerlink" href="#key-bindings" title="Permalink to this headline">¶</a></h3>
<p>In this section, ‘C’ refers to the <kbd class="kbd docutils literal notranslate">Control</kbd> key on Windows and Unix and
the <kbd class="kbd docutils literal notranslate">Command</kbd> key on macOS.</p>
<ul>
<li><p class="first"><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>
<li><p class="first"><kbd class="kbd docutils literal notranslate">C-Backspace</kbd> delete word left; <kbd class="kbd docutils literal notranslate">C-Del</kbd> delete word to the right</p>
</li>
<li><p class="first">Arrow keys and <kbd class="kbd docutils literal notranslate">Page Up</kbd>/<kbd class="kbd docutils literal notranslate">Page Down</kbd> to move around</p>
</li>
<li><p class="first"><kbd class="kbd docutils literal notranslate">C-LeftArrow</kbd> and <kbd class="kbd docutils literal notranslate">C-RightArrow</kbd> moves by words</p>
</li>
<li><p class="first"><kbd class="kbd docutils literal notranslate">Home</kbd>/<kbd class="kbd docutils literal notranslate">End</kbd> go to begin/end of line</p>
</li>
<li><p class="first"><kbd class="kbd docutils literal notranslate">C-Home</kbd>/<kbd class="kbd docutils literal notranslate">C-End</kbd> go to begin/end of file</p>
</li>
<li><p class="first">Some useful Emacs bindings are inherited from Tcl/Tk:</p>
<blockquote>
<div><ul class="simple">
<li><kbd class="kbd docutils literal notranslate">C-a</kbd> beginning of line</li>
<li><kbd class="kbd docutils literal notranslate">C-e</kbd> end of line</li>
<li><kbd class="kbd docutils literal notranslate">C-k</kbd> kill line (but doesn’t put it in clipboard)</li>
<li><kbd class="kbd docutils literal notranslate">C-l</kbd> center window around the insertion point</li>
<li><kbd class="kbd docutils literal notranslate">C-b</kbd> go backward one character without deleting (usually you can
also use the cursor key for this)</li>
<li><kbd class="kbd docutils literal notranslate">C-f</kbd> go forward one character without deleting (usually you can
also use the cursor key for this)</li>
<li><kbd class="kbd docutils literal notranslate">C-p</kbd> go up one line (usually you can also use the cursor key for
this)</li>
<li><kbd class="kbd docutils literal notranslate">C-d</kbd> delete next character</li>
</ul>
</div></blockquote>
</li>
</ul>
<p>Standard keybindings (like <kbd class="kbd docutils literal notranslate">C-c</kbd> to copy and <kbd class="kbd docutils literal notranslate">C-v</kbd> to paste)
may work. Keybindings are selected in the Configure IDLE dialog.</p>
</div>
<div class="section" id="automatic-indentation">
<h3>Automatic indentation<a class="headerlink" href="#automatic-indentation" title="Permalink to this headline">¶</a></h3>
<p>After a block-opening statement, the next line is indented by 4 spaces (in the
Python Shell window by one tab). After certain keywords (break, return etc.)
the next line is dedented. In leading indentation, <kbd class="kbd docutils literal notranslate">Backspace</kbd> deletes up
to 4 spaces if they are there. <kbd class="kbd docutils literal notranslate">Tab</kbd> inserts spaces (in the Python
Shell window one tab), number depends on Indent width. Currently, tabs
are restricted to four spaces due to Tcl/Tk limitations.</p>
<p>See also the indent/dedent region commands on the
<a class="reference internal" href="#format-menu"><span class="std std-ref">Format menu</span></a>.</p>
</div>
<div class="section" id="completions">
<span id="id3"></span><h3>Completions<a class="headerlink" href="#completions" title="Permalink to this headline">¶</a></h3>
<p>Completions are supplied for functions, classes, and attributes of classes,
both built-in and user-defined. Completions are also provided for
filenames.</p>
<p>The AutoCompleteWindow (ACW) will open after a predefined delay (default is
two seconds) after a ‘.’ or (in a string) an os.sep is typed. If after one
of those characters (plus zero or more other characters) a tab is typed
the ACW will open immediately if a possible continuation is found.</p>
<p>If there is only one possible completion for the characters entered, a
<kbd class="kbd docutils literal notranslate">Tab</kbd> will supply that completion without opening the ACW.</p>
<p>‘Show Completions’ will force open a completions window, by default the
<kbd class="kbd docutils literal notranslate">C-space</kbd> will open a completions window. In an empty
string, this will contain the files in the current directory. On a
blank line, it will contain the built-in and user-defined functions and
classes in the current namespaces, plus any modules imported. If some
characters have been entered, the ACW will attempt to be more specific.</p>
<p>If a string of characters is typed, the ACW selection will jump to the
entry most closely matching those characters. Entering a <kbd class="kbd docutils literal notranslate">tab</kbd> will
cause the longest non-ambiguous match to be entered in the Editor window or
Shell. Two <kbd class="kbd docutils literal notranslate">tab</kbd> in a row will supply the current ACW selection, as
will return or a double click. Cursor keys, Page Up/Down, mouse selection,
and the scroll wheel all operate on the ACW.</p>
<p>“Hidden” attributes can be accessed by typing the beginning of hidden
name after a ‘.’, e.g. ‘_’. This allows access to modules with
<code class="docutils literal notranslate"><span class="pre">__all__</span></code> set, or to class-private attributes.</p>
<p>Completions and the ‘Expand Word’ facility can save a lot of typing!</p>
<p>Completions are currently limited to those in the namespaces. Names in
an Editor window which are not via <code class="docutils literal notranslate"><span class="pre">__main__</span></code> and <a class="reference internal" href="sys.html#sys.modules" title="sys.modules"><code class="xref py py-data docutils literal notranslate"><span class="pre">sys.modules</span></code></a> will
not be found. Run the module once with your imports to correct this situation.
Note that IDLE itself places quite a few modules in sys.modules, so
much can be found by default, e.g. the re module.</p>
<p>If you don’t like the ACW popping up unbidden, simply make the delay
longer or disable the extension.</p>
</div>
<div class="section" id="calltips">
<span id="id4"></span><h3>Calltips<a class="headerlink" href="#calltips" title="Permalink to this headline">¶</a></h3>
<p>A calltip is shown when one types <kbd class="kbd docutils literal notranslate">(</kbd> after the name of an <em>accessible</em>
function. A name expression may include dots and subscripts. A calltip
remains until it is clicked, the cursor is moved out of the argument area,
or <kbd class="kbd docutils literal notranslate">)</kbd> is typed. When the cursor is in the argument part of a definition,
the menu or shortcut display a calltip.</p>
<p>A calltip consists of the function signature and the first line of the
docstring. For builtins without an accessible signature, the calltip
consists of all lines up the fifth line or the first blank line. These
details may change.</p>
<p>The set of <em>accessible</em> functions depends on what modules have been imported
into the user process, including those imported by Idle itself,
and what definitions have been run, all since the last restart.</p>
<p>For example, restart the Shell and enter <code class="docutils literal notranslate"><span class="pre">itertools.count(</span></code>. A calltip
appears because Idle imports itertools into the user process for its own use.
(This could change.) Enter <code class="docutils literal notranslate"><span class="pre">turtle.write(</span></code> and nothing appears. Idle does
not import turtle. The menu or shortcut do nothing either. Enter
<code class="docutils literal notranslate"><span class="pre">import</span> <span class="pre">turtle</span></code> and then <code class="docutils literal notranslate"><span class="pre">turtle.write(</span></code> will work.</p>
<p>In an editor, import statements have no effect until one runs the file. One
might want to run a file after writing the import statements at the top,
or immediately run an existing file before editing.</p>
</div>
<div class="section" id="code-context">
<span id="id5"></span><h3>Code Context<a class="headerlink" href="#code-context" title="Permalink to this headline">¶</a></h3>
<p>Within an editor window containing Python code, code context can be toggled
in order to show or hide a pane at the top of the window. When shown, this
pane freezes the opening lines for block code, such as those beginning with
<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
out of view. The size of the pane will be expanded and contracted as needed
to show the all current levels of context, up to the maximum number of
lines defined in the Configure IDLE dialog (which defaults to 15). If there
are no current context lines and the feature is toggled on, a single blank
line will display. Clicking on a line in the context pane will move that
line to the top of the editor.</p>
<p>The text and background colors for the context pane can be configured under
the Highlights tab in the Configure IDLE dialog.</p>
</div>
<div class="section" id="python-shell-window">
<h3>Python Shell window<a class="headerlink" href="#python-shell-window" title="Permalink to this headline">¶</a></h3>
<p>With IDLE’s Shell, one enters, edits, and recalls complete statements.
Most consoles and terminals only work with a single physical line at a time.</p>
<p>When one pastes code into Shell, it is not compiled and possibly executed
until one hits <kbd class="kbd docutils literal notranslate">Return</kbd>. One may edit pasted code first.
If one pastes more that one statement into Shell, the result will be a
<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>
<p>The editing features described in previous subsections work when entering
code interactively. IDLE’s Shell window also responds to the following keys.</p>
<ul>
<li><p class="first"><kbd class="kbd docutils literal notranslate">C-c</kbd> interrupts executing command</p>
</li>
<li><p class="first"><kbd class="kbd docutils literal notranslate">C-d</kbd> sends end-of-file; closes window if typed at a <code class="docutils literal notranslate"><span class="pre">>>></span></code> prompt</p>
</li>
<li><p class="first"><kbd class="kbd docutils literal notranslate">Alt-/</kbd> (Expand word) is also useful to reduce typing</p>
<p>Command history</p>
<ul class="simple">
<li><kbd class="kbd docutils literal notranslate">Alt-p</kbd> retrieves previous command matching what you have typed. On
macOS use <kbd class="kbd docutils literal notranslate">C-p</kbd>.</li>
<li><kbd class="kbd docutils literal notranslate">Alt-n</kbd> retrieves next. On macOS use <kbd class="kbd docutils literal notranslate">C-n</kbd>.</li>
<li><kbd class="kbd docutils literal notranslate">Return</kbd> while on any previous command retrieves that command</li>
</ul>
</li>
</ul>
</div>
<div class="section" id="text-colors">
<h3>Text colors<a class="headerlink" href="#text-colors" title="Permalink to this headline">¶</a></h3>
<p>Idle defaults to black on white text, but colors text with special meanings.
For the shell, these are shell output, shell error, user output, and
user error. For Python code, at the shell prompt or in an editor, these are
keywords, builtin class and function names, names following <code class="docutils literal notranslate"><span class="pre">class</span></code> and
<code class="docutils literal notranslate"><span class="pre">def</span></code>, strings, and comments. For any text window, these are the cursor (when
present), found text (when possible), and selected text.</p>
<p>Text coloring is done in the background, so uncolorized text is occasionally
visible. To change the color scheme, use the Configure IDLE dialog
Highlighting tab. The marking of debugger breakpoint lines in the editor and
text in popups and dialogs is not user-configurable.</p>
</div>
</div>
<div class="section" id="startup-and-code-execution">
<h2>Startup and code execution<a class="headerlink" href="#startup-and-code-execution" title="Permalink to this headline">¶</a></h2>
<p>Upon startup with the <code class="docutils literal notranslate"><span class="pre">-s</span></code> option, IDLE will execute the file referenced by
the 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>.
IDLE 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
referenced is run. If <code class="docutils literal notranslate"><span class="pre">IDLESTARTUP</span></code> is not present, IDLE checks for
<code class="docutils literal notranslate"><span class="pre">PYTHONSTARTUP</span></code>. Files referenced by these environment variables are
convenient places to store functions that are used frequently from the IDLE
shell, or for executing import statements to import common modules.</p>
<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
Tk file is loaded unconditionally. This additional file is <code class="docutils literal notranslate"><span class="pre">.Idle.py</span></code> and is
looked for in the user’s home directory. Statements in this file will be
executed in the Tk namespace, so this file is not useful for importing
functions to be used from IDLE’s Python shell.</p>
<div class="section" id="command-line-usage">
<h3>Command line usage<a class="headerlink" href="#command-line-usage" title="Permalink to this headline">¶</a></h3>
<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] ...
-c command run command in the shell window
-d enable debugger and open shell window
-e open editor window
-h print help message with legal combinations and exit
-i open shell window
-r file run file in shell window
-s run $IDLESTARTUP or $PYTHONSTARTUP first, in shell window
-t title set title of shell window
- run stdin in shell (- must be last option before args)
</pre></div>
</div>
<p>If there are arguments:</p>
<ul class="simple">
<li>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
<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>,
or <code class="docutils literal notranslate"><span class="pre">'-r'</span></code>. No editor window is opened, even if that is the default
set in the Options dialog.</li>
<li>Otherwise, arguments are files opened for editing and
<code class="docutils literal notranslate"><span class="pre">sys.argv</span></code> reflects the arguments passed to IDLE itself.</li>
</ul>
</div>
<div class="section" id="startup-failure">
<h3>Startup failure<a class="headerlink" href="#startup-failure" title="Permalink to this headline">¶</a></h3>
<p>IDLE uses a socket to communicate between the IDLE GUI process and the user
code execution process. A connection must be established whenever the Shell
starts or restarts. (The latter is indicated by a divider line that says
‘RESTART’). If the user process fails to connect to the GUI process, it
displays a <code class="docutils literal notranslate"><span class="pre">Tk</span></code> error box with a ‘cannot connect’ message that directs the
user here. It then exits.</p>
<p>A common cause of failure is a user-written file with the same name as a
standard library module, such as <em>random.py</em> and <em>tkinter.py</em>. When such a
file is located in the same directory as a file that is about to be run,
IDLE cannot import the stdlib file. The current fix is to rename the
user file.</p>
<p>Though less common than in the past, an antivirus or firewall program may
stop the connection. If the program cannot be taught to allow the
connection, then it must be turned off for IDLE to work. It is safe to
allow this internal connection because no data is visible on external
ports. A similar problem is a network mis-configuration that blocks
connections.</p>
<p>Python installation issues occasionally stop IDLE: multiple versions can
clash, or a single installation might need admin access. If one undo the
clash, or cannot or does not want to run as admin, it might be easiest to
completely remove Python and start over.</p>
<p>A zombie pythonw.exe process could be a problem. On Windows, use Task
Manager to detect and stop one. Sometimes a restart initiated by a program
crash or Keyboard Interrupt (control-C) may fail to connect. Dismissing
the error box or Restart Shell on the Shell menu may fix a temporary problem.</p>
<p>When IDLE first starts, it attempts to read user configuration files in
~/.idlerc/ (~ is one’s home directory). If there is a problem, an error
message should be displayed. Leaving aside random disk glitches, this can
be prevented by never editing the files by hand, using the configuration
dialog, under Options, instead Options. Once it happens, the solution may
be to delete one or more of the configuration files.</p>
<p>If IDLE quits with no message, and it was not started from a console, try
starting from a console (<code class="docutils literal notranslate"><span class="pre">python</span> <span class="pre">-m</span> <span class="pre">idlelib)</span></code> and see if a message appears.</p>
</div>
<div class="section" id="running-user-code">
<h3>Running user code<a class="headerlink" href="#running-user-code" title="Permalink to this headline">¶</a></h3>
<p>With rare exceptions, the result of executing Python code with IDLE is
intended to be the same as executing the same code by the default method,
directly with Python in a text-mode system console or terminal window.
However, the different interface and operation occasionally affect
visible results. For instance, <code class="docutils literal notranslate"><span class="pre">sys.modules</span></code> starts with more entries,
and <code class="docutils literal notranslate"><span class="pre">threading.activeCount()</span></code> returns 2 instead of 1.</p>
<p>By default, IDLE runs user code in a separate OS process rather than in
the user interface process that runs the shell and editor. In the execution
process, 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>
with objects that get input from and send output to the Shell window.
The 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
<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>
<p>When Shell has the focus, it controls the keyboard and screen. This is
normally transparent, but functions that directly access the keyboard
and screen will not work. These include system-specific functions that
determine whether a key has been pressed and if so, which.</p>
<p>IDLE’s standard stream replacements are not inherited by subprocesses
created in the execution process, whether directly by user code or by modules
such as multiprocessing. If such subprocess use <code class="docutils literal notranslate"><span class="pre">input</span></code> from sys.stdin
or <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,
IDLE should be started in a command line window. The secondary subprocess
will then be attached to that window for input and output.</p>
<p>The IDLE code running in the execution process adds frames to the call stack
that would not be there otherwise. IDLE wraps <code class="docutils literal notranslate"><span class="pre">sys.getrecursionlimit</span></code> and
<code class="docutils literal notranslate"><span class="pre">sys.setrecursionlimit</span></code> to reduce the effect of the additional stack frames.</p>
<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>,
IDLE’s changes are lost and input from the keyboard and output to the screen
will not work correctly.</p>
<p>When user code raises SystemExit either directly or by calling sys.exit, IDLE
returns to a Shell prompt instead of exiting.</p>
</div>
<div class="section" id="user-output-in-shell">
<h3>User output in Shell<a class="headerlink" href="#user-output-in-shell" title="Permalink to this headline">¶</a></h3>
<p>When a program outputs text, the result is determined by the
corresponding output device. When IDLE executes user 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> are connected to the display area of IDLE’s Shell. Some of
its features are inherited from the underlying Tk Text widget. Others
are programmed additions. Where it matters, Shell is designed for development
rather than production runs.</p>
<p>For instance, Shell never throws away output. A program that sends unlimited
output to Shell will eventually fill memory, resulting in a memory error.
In contrast, some system text windows only keep the last n lines of output.
A Windows console, for instance, keeps a user-settable 1 to 9999 lines,
with 300 the default.</p>
<p>A Tk Text widget, and hence IDLE’s Shell, displays characters (codepoints) in
the BMP (Basic Multilingual Plane) subset of Unicode. Which characters are
displayed with a proper glyph and which with a replacement box depends on the
operating system and installed fonts. Tab characters cause the following text
to begin after the next tab stop. (They occur every 8 ‘characters’). Newline
characters cause following text to appear on a new line. Other control
characters are ignored or displayed as a space, box, or something else,
depending on the operating system and font. (Moving the text cursor through
such output with arrow keys may exhibit some surprising spacing behavior.)</p>
<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>
<span class="gp">>>> </span><span class="nb">len</span><span class="p">(</span><span class="n">s</span><span class="p">)</span>
<span class="go">14</span>
<span class="gp">>>> </span><span class="n">s</span> <span class="c1"># Display repr(s)</span>
<span class="go">'a\tb\x07<\x02><\r>\x08c\nd'</span>
<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>
<span class="go"># Result varies by OS and font. Try it.</span>
</pre></div>
</div>
<p>The <code class="docutils literal notranslate"><span class="pre">repr</span></code> function is used for interactive echo of expression
values. It returns an altered version of the input string in which
control codes, some BMP codepoints, and all non-BMP codepoints are
replaced with escape codes. As demonstrated above, it allows one to
identify the characters in a string, regardless of how they are displayed.</p>
<p>Normal and error output are generally kept separate (on separate lines)
from code input and each other. They each get different highlight colors.</p>
<p>For SyntaxError tracebacks, the normal ‘^’ marking where the error was
detected is replaced by coloring the text with an error highlight.
When code run from a file causes other exceptions, one may right click
on a traceback line to jump to the corresponding line in an IDLE editor.
The file will be opened if necessary.</p>
<p>Shell has a special facility for squeezing output lines down to a
‘Squeezed text’ label. This is done automatically
for output over N lines (N = 50 by default).
N can be changed in the PyShell section of the General
page of the Settings dialog. Output with fewer lines can be squeezed by
right clicking on the output. This can be useful lines long enough to slow
down scrolling.</p>
<p>Squeezed output is expanded in place by double-clicking the label.
It can also be sent to the clipboard or a separate view window by
right-clicking the label.</p>
</div>
<div class="section" id="developing-tkinter-applications">
<h3>Developing tkinter applications<a class="headerlink" href="#developing-tkinter-applications" title="Permalink to this headline">¶</a></h3>
<p>IDLE is intentionally different from standard Python in order to
facilitate 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>
<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
in IDLE and a tk window appears. In standard Python, one must also enter
<code class="docutils literal notranslate"><span class="pre">root.update()</span></code> to see the window. IDLE does the equivalent in the
background, about 20 times a second, which is about every 50 milliseconds.
Next 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,
nothing visibly changes in standard Python until one enters <code class="docutils literal notranslate"><span class="pre">root.update()</span></code>.</p>
<p>Most tkinter programs run <code class="docutils literal notranslate"><span class="pre">root.mainloop()</span></code>, which usually does not
return until the tk app is destroyed. If the program is run with
<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
appear until <code class="docutils literal notranslate"><span class="pre">mainloop()</span></code> returns, at which time there is nothing left
to interact with.</p>
<p>When running a tkinter program from an IDLE editor, one can comment out
the mainloop call. One then gets a shell prompt immediately and can
interact with the live application. One just has to remember to
re-enable the mainloop call when running in standard Python.</p>
</div>
<div class="section" id="running-without-a-subprocess">
<h3>Running without a subprocess<a class="headerlink" href="#running-without-a-subprocess" title="Permalink to this headline">¶</a></h3>
<p>By default, IDLE executes user code in a separate subprocess via a socket,
which uses the internal loopback interface. This connection is not
externally visible and no data is sent to or received from the Internet.
If firewall software complains anyway, you can ignore it.</p>
<p>If the attempt to make the socket connection fails, Idle will notify you.
Such failures are sometimes transient, but if persistent, the problem
may be either a firewall blocking the connection or misconfiguration of
a particular system. Until the problem is fixed, one can run Idle with
the -n command line switch.</p>
<p>If IDLE is started with the -n command line switch it will run in a
single process and will not create the subprocess which runs the RPC
Python execution server. This can be useful if Python cannot create
the subprocess or the RPC socket interface on your platform. However,
in this mode user code is not isolated from IDLE itself. Also, the
environment is not restarted when Run/Run Module (F5) is selected. If
your code has been modified, you must reload() the affected modules and
re-import any specific items (e.g. from foo import baz) if the changes
are to take effect. For these reasons, it is preferable to run IDLE
with the default subprocess if at all possible.</p>
<div class="deprecated">
<p><span class="versionmodified deprecated">Deprecated since version 3.4.</span></p>
</div>
</div>
</div>
<div class="section" id="help-and-preferences">
<h2>Help and preferences<a class="headerlink" href="#help-and-preferences" title="Permalink to this headline">¶</a></h2>
<div class="section" id="help-sources">
<span id="id6"></span><h3>Help sources<a class="headerlink" href="#help-sources" title="Permalink to this headline">¶</a></h3>
<p>Help menu entry “IDLE Help” displays a formatted html version of the
IDLE chapter of the Library Reference. The result, in a read-only
tkinter text window, is close to what one sees in a web browser.
Navigate through the text with a mousewheel,
the scrollbar, or up and down arrow keys held down.
Or click the TOC (Table of Contents) button and select a section
header in the opened box.</p>
<p>Help menu entry “Python Docs” opens the extensive sources of help,
including tutorials, available at docs.python.org/x.y, where ‘x.y’
is the currently running Python version. If your system
has an off-line copy of the docs (this may be an installation option),
that will be opened instead.</p>
<p>Selected URLs can be added or removed from the help menu at any time using the
General tab of the Configure IDLE dialog .</p>
</div>
<div class="section" id="setting-preferences">
<span id="preferences"></span><h3>Setting preferences<a class="headerlink" href="#setting-preferences" title="Permalink to this headline">¶</a></h3>
<p>The font preferences, highlighting, keys, and general preferences can be
changed via Configure IDLE on the Option menu.
Non-default user settings are saved in a .idlerc directory in the user’s
home directory. Problems caused by bad user configuration files are solved
by editing or deleting one or more of the files in .idlerc.</p>
<p>On the Font tab, see the text sample for the effect of font face and size
on multiple characters in multiple languages. Edit the sample to add
other characters of personal interest. Use the sample to select
monospaced fonts. If particular characters have problems in Shell or an
editor, add them to the top of the sample and try changing first size
and then font.</p>
<p>On the Highlights and Keys tab, select a built-in or custom color theme
and key set. To use a newer built-in color theme or key set with older
IDLEs, save it as a new custom theme or key set and it well be accessible
to older IDLEs.</p>
</div>
<div class="section" id="idle-on-macos">
<h3>IDLE on macOS<a class="headerlink" href="#idle-on-macos" title="Permalink to this headline">¶</a></h3>
<p>Under System Preferences: Dock, one can set “Prefer tabs when opening
documents” to “Always”. This setting is not compatible with the tk/tkinter
GUI framework used by IDLE, and it breaks a few IDLE features.</p>
</div>
<div class="section" id="extensions">
<h3>Extensions<a class="headerlink" href="#extensions" title="Permalink to this headline">¶</a></h3>
<p>IDLE contains an extension facility. Preferences for extensions can be
changed with the Extensions tab of the preferences dialog. See the
beginning of config-extensions.def in the idlelib directory for further
information. The only current default extension is zzdummy, an example
also used for testing.</p>
</div>
</div>
</div>
</div>
</div>
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<h3><a href="../contents.html">Table of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#">IDLE</a><ul>
<li><a class="reference internal" href="#menus">Menus</a><ul>
<li><a class="reference internal" href="#file-menu-shell-and-editor">File menu (Shell and Editor)</a></li>
<li><a class="reference internal" href="#edit-menu-shell-and-editor">Edit menu (Shell and Editor)</a></li>
<li><a class="reference internal" href="#format-menu-editor-window-only">Format menu (Editor window only)</a></li>
<li><a class="reference internal" href="#run-menu-editor-window-only">Run menu (Editor window only)</a></li>
<li><a class="reference internal" href="#shell-menu-shell-window-only">Shell menu (Shell window only)</a></li>
<li><a class="reference internal" href="#debug-menu-shell-window-only">Debug menu (Shell window only)</a></li>
<li><a class="reference internal" href="#options-menu-shell-and-editor">Options menu (Shell and Editor)</a></li>
<li><a class="reference internal" href="#window-menu-shell-and-editor">Window menu (Shell and Editor)</a></li>
<li><a class="reference internal" href="#help-menu-shell-and-editor">Help menu (Shell and Editor)</a></li>
<li><a class="reference internal" href="#context-menus">Context Menus</a></li>
</ul>
</li>
<li><a class="reference internal" href="#editing-and-navigation">Editing and navigation</a><ul>
<li><a class="reference internal" href="#editor-windows">Editor windows</a></li>
<li><a class="reference internal" href="#key-bindings">Key bindings</a></li>
<li><a class="reference internal" href="#automatic-indentation">Automatic indentation</a></li>
<li><a class="reference internal" href="#completions">Completions</a></li>
<li><a class="reference internal" href="#calltips">Calltips</a></li>
<li><a class="reference internal" href="#code-context">Code Context</a></li>
<li><a class="reference internal" href="#python-shell-window">Python Shell window</a></li>
<li><a class="reference internal" href="#text-colors">Text colors</a></li>
</ul>
</li>
<li><a class="reference internal" href="#startup-and-code-execution">Startup and code execution</a><ul>
<li><a class="reference internal" href="#command-line-usage">Command line usage</a></li>
<li><a class="reference internal" href="#startup-failure">Startup failure</a></li>
<li><a class="reference internal" href="#running-user-code">Running user code</a></li>
<li><a class="reference internal" href="#user-output-in-shell">User output in Shell</a></li>
<li><a class="reference internal" href="#developing-tkinter-applications">Developing tkinter applications</a></li>
<li><a class="reference internal" href="#running-without-a-subprocess">Running without a subprocess</a></li>
</ul>
</li>
<li><a class="reference internal" href="#help-and-preferences">Help and preferences</a><ul>
<li><a class="reference internal" href="#help-sources">Help sources</a></li>
<li><a class="reference internal" href="#setting-preferences">Setting preferences</a></li>
<li><a class="reference internal" href="#idle-on-macos">IDLE on macOS</a></li>
<li><a class="reference internal" href="#extensions">Extensions</a></li>
</ul>
</li>
</ul>
</li>
</ul>
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