ソースコード: Lib/idlelib/

IDLE は Python の統合開発環境で、学習用環境です。

IDLE は次のような特徴があります:

  • tkinter GUIツールキットを使って、100% ピュア Python でコーディングされています

  • クロスプラットホーム: Windows, Unix, macOS で動作します

  • コード入力、出力、エラーメッセージの色付け機能を持った Python shell (対話的インタプリタ) ウィンドウ

  • 多段 Undo、 Python 対応の色づけ、自動的な字下げ、呼び出し情報の表示、自動補完、他たくさんの機能をもつマルチウィンドウ・テキストエディタ

  • 任意のウィンドウ内での検索、エディタウィンドウ内での置換、複数ファイルを跨いだ検索 (grep)

  • 永続的なブレイクポイント、ステップ実行、グローバルとローカル名前空間の視覚化機能を持ったデバッガ

  • 設定、ブラウザ群、ほかダイアログ群


Editor windows

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.

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.

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.

Key bindings

In this section, 'C' refers to the Control key on Windows and Unix and the Command key on macOS.

  • Backspace は左側を削除し、 Del は右側を削除します。

  • C-Backspace は語単位で左側を削除、 C-Del は語単位で右側を削除します。

  • 矢印キーと Page Up/Page Down はそれぞれその通りに移動します。

  • C-LeftArrowC-RightArrow は語単位で移動します。

  • Home/End は行の始め/終わりへ移動します。

  • C-Home/C-End はファイルの始め/終わりへ移動します。

  • いくつかの有用な Emacs バインディングが Tcl/Tk から継承されています:

    • C-a で行頭へ移動。

    • C-e で行末へ移動。

    • C-k で行を削除 (ただしクリップボードには入りません)。

    • C-l で挿入ポイントをウィンドウの中心にする。

    • C-b go backward one character without deleting (usually you can also use the cursor key for this)

    • C-f で一文字分文字削除なしで進む (通常、これはカーソルキーでもできます)。

    • C-p で一行上へ移動 (通常、これはカーソルキーでもできます)。

    • C-d で次の文字を削除。

標準的なキーバインディング (C-c がコピーで C-v がペースト、など) は機能するかもしれません。キーバインディングは Configure IDLE ダイアログで選択します。


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, Backspace deletes up to 4 spaces if they are there. Tab 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.

See also the indent/dedent region commands on the Format menu.

補完 (Completions)

Completions are supplied, when requested and available, for module names, attributes of classes or functions, or filenames. Each request method displays a completion box with existing names. (See tab completions below for an exception.) For any box, change the name being completed and the item highlighted in the box by typing and deleting characters; by hitting Up, Down, PageUp, PageDown, Home, and End keys; and by a single click within the box. Close the box with Escape, Enter, and double Tab keys or clicks outside the box. A double click within the box selects and closes.

One way to open a box is to type a key character and wait for a predefined interval. This defaults to 2 seconds; customize it in the settings dialog. (To prevent auto popups, set the delay to a large number of milliseconds, such as 100000000.) For imported module names or class or function attributes, type '.'. For filenames in the root directory, type os.sep or data:os.altsep immediately after an opening quote. (On Windows, one can specify a drive first.) Move into subdirectories by typing a directory name and a separator.

Instead of waiting, or after a box is closed, open a completion box immediately with Show Completions on the Edit menu. The default hot key is C-space. If one types a prefix for the desired name before opening the box, the first match or near miss is made visible. The result is the same as if one enters a prefix after the box is displayed. Show Completions after a quote completes filenames in the current directory instead of a root directory.

Hitting Tab after a prefix usually has the same effect as Show Completions. (With no prefix, it indents.) However, if there is only one match to the prefix, that match is immediately added to the editor text without opening a box.

Invoking 'Show Completions', or hitting Tab after a prefix, outside of a string and without a preceding '.' opens a box with keywords, builtin names, and available module-level names.

When editing code in an editor (as oppose to Shell), increase the available module-level names by running your code and not restarting the Shell thereafter. This is especially useful after adding imports at the top of a file. This also increases possible attribute completions.

Completion boxes intially exclude names beginning with '_' or, for modules, not included in '__all__'. The hidden names can be accessed by typing '_' after '.', either before or after the box is opened.

呼び出しヒント (Calltips)

calltip は、 アクセス可能な 関数名に続けて ( をタイプすると表示されます。名前の式ではドットや添え字を含んでいても構いません。calltip は、それをクリックするか、カーソルが引数のエリアから外れるか、 ) をタイプするまでは表示されたままとなります。カーソルが引数部分にあれば、メニューやショートカットで calltip を表示できます。

calltip では関数シグニチャとドキュメンテーション文字列の最初の行を表示します。アクセスできるシグニチャがない組み込み関数の場合は、ドキュメンテーション文字列から、5 行目までの全行か最初の空行までの全行を表示します。いまのところは上記の通りですが、この詳細は変更される場合があります。

アクセス可能な 関数の集合は IDLE 自身がインポートしたものも含め、最後に IDLE を再スタートしてから既にユーザプロセス内で何がインポートされたのか、どの定義が実行されたのかに拠ります。

たとえば Shell を再スタートして (訳注: itertools をインポートせずに) itertools.count( とタイプしてみてください。 IDLE が itertools を自身の使用のためにユーザプロセス内にインポートするので、calltip が表示されます。 (これは変更されるかもしれません)。 turtle.write( と入力しても、何も表示されないでしょう。これは、IDLE は turtle をインポートしないためです。メニューやショートカットを使用しても、何も起こりません。 import turtle と入力した後なら、 turtle.write( で calltip が表示されるようになります。

Editor 内では import 文そのものだけでは、一度でもそのファイルを実行しない限り calltip に影響しません。ファイルの上の方でインポート文を書いたら実行するとか、あるいは既存のものは編集前に実行してしまえ、というのも良いかもしれませんね。

Code Context

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 class, def, or if 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.

The text and background colors for the context pane can be configured under the Highlights tab in the Configure IDLE dialog.

Python Shell ウィンドウ

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.

When one pastes code into Shell, it is not compiled and possibly executed until one hits Return. One may edit pasted code first. If one pastes more that one statement into Shell, the result will be a SyntaxError when multiple statements are compiled as if they were one.

The editing features described in previous subsections work when entering code interactively. IDLE's Shell window also responds to the following keys.

  • C-c で実行中のコマンドを中断します。

  • C-d でファイル終端 (end-of-file) を送り、 >>> プロンプトでタイプしていた場合はウィンドウを閉じます。

  • Alt-/ (語を展開します) もタイピングを減らすのに便利です。


    • Alt-p retrieves previous command matching what you have typed. On macOS use C-p.

    • Alt-n retrieves next. On macOS use C-n.

    • Return は、以前のコマンドを取り出しているときは、そのコマンドを取り出します。


IDLE の表示はデフォルトで白背景に黒字ですが、以下のような特別な意味を持ったテキストには色が付きす。Shell では shell 出力、 shell エラー、ユーザエラー。Python コードでは Shell プロンプト内や Editor でのキーワード、組み込みクラスや組み込み関数の名前、 classdef に続く名前、文字列、そしてコメント。どんなテキストウィンドウでも、カーソル (あれば)、検索で合致したテキスト (あれば)、そして選択されているテキストには色が付きます。

このテキストの色付けはバックグラウンドで行われるため、たまに色が付いてない状態が見えてしまいます。カラースキームは、 Configure IDLE [IDLE の設定] ダイアログの Highlighting タブで変更できます。ただし、エディタ内のデバッガブレークポイント行のマーキングと、ポップアップとダイアログないのテキストの色は、ユーザーにより変更することはできません。


-s オプションとともに起動すると、IDLE は環境変数 IDLESTARTUPPYTHONSTARTUP で参照されているファイルを実行します。 IDLE はまず IDLESTARTUP をチェックし、あれば参照しているファイルを実行します。 IDLESTARTUP が無ければ、IDLE は PYTHONSTARTUP をチェックします。これらの環境変数で参照されているファイルは、IDLE シェルでよく使う関数を置いたり、一般的なモジュールの import 文を実行するのに便利です。

加えて、Tk もスタートアップファイルがあればそれをロードします。その Tk のファイルは無条件にロードされることに注意してください。このファイルは で、ユーザーのホームディレクトリから探されます。このファイルの中の文は Tk の名前空間で実行されるので、IDLE の Python シェルで使う関数を import するのには便利ではありません。

コマンドラインの使い方 [-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)

引数がある場合 (訳注: 以下の説明、たぶん実情に反してますが一応訳しています):

  • -, -c, -r のどれかを使う場合、全ての引数は sys.argv[1:...] に入り、 sys.argv[0] には '', '-c', '-r' の、与えたものが入ります。 Options ダイアログでデフォルトだったとしても Editor ウィンドウが開くことはありません。

  • これ以外の場合は引数は編集対象のファイルとして開かれて、 sys.argv には IDLE そのものに渡された引数が反映されます。

Startup failure

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 Tk error box with a 'cannot connect' message that directs the user here. It then exits.

A common cause of failure is a user-written file with the same name as a standard library module, such as and 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.

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.

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.

A zombie pythonw.exe process could be a problem. On Windows, use Task Manager to check for one and stop it if there is. Sometimes a restart initiated by a program crash or Keyboard Interrupt (control-C) may fail to connect. Dismissing the error box or using Restart Shell on the Shell menu may fix a temporary problem.

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. Instead, use the configuration dialog, under Options. Once there is an error in a user configuration file, the best solution may be to delete it and start over with the settings dialog.

If IDLE quits with no message, and it was not started from a console, try starting it from a console or terminal (python -m idlelib) and see if this results in an error message.

Running user code

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, sys.modules starts with more entries, and threading.activeCount() returns 2 instead of 1.

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 sys.stdin, sys.stdout, and sys.stderr with objects that get input from and send output to the Shell window. The original values stored in sys.__stdin__, sys.__stdout__, and sys.__stderr__ are not touched, but may be None.

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.

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 input from sys.stdin or print or write 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.

The IDLE code running in the execution process adds frames to the call stack that would not be there otherwise. IDLE wraps sys.getrecursionlimit and sys.setrecursionlimit to reduce the effect of the additional stack frames.

If sys is reset by user code, such as with importlib.reload(sys), IDLE's changes are lost and input from the keyboard and output to the screen will not work correctly.

When user code raises SystemExit either directly or by calling sys.exit, IDLE returns to a Shell prompt instead of exiting.

User output in Shell

When a program outputs text, the result is determined by the corresponding output device. When IDLE executes user code, sys.stdout and sys.stderr 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.

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.

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.)

>>> s = 'a\tb\a<\x02><\r>\bc\nd'  # Enter 22 chars.
>>> len(s)
>>> s  # Display repr(s)
>>> print(s, end='')  # Display s as is.
# Result varies by OS and font.  Try it.

The repr 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.

Normal and error output are generally kept separate (on separate lines) from code input and each other. They each get different highlight colors.

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.

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.

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.

Developing tkinter applications

IDLE is intentionally different from standard Python in order to facilitate development of tkinter programs. Enter import tkinter as tk; root = tk.Tk() in standard Python and nothing appears. Enter the same in IDLE and a tk window appears. In standard Python, one must also enter root.update() to see the window. IDLE does the equivalent in the background, about 20 times a second, which is about every 50 milliseconds. Next enter b = tk.Button(root, text='button'); b.pack(). Again, nothing visibly changes in standard Python until one enters root.update().

Most tkinter programs run root.mainloop(), which usually does not return until the tk app is destroyed. If the program is run with python -i or from an IDLE editor, a >>> shell prompt does not appear until mainloop() returns, at which time there is nothing left to interact with.

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.


デフォルトでは、IDLE でのユーザコードの実行は、内部的なループバックインターフェイスを使用する、ソケット経由の分離されたサブプロセスで行われます。この接続は外部からは見えませんし、インターネットとのデータの送受信は行われません。ファイアウォールソフトウェアの警告が発生しても、無視して構いません。

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.

IDLE を -n コマンドラインスイッチを使って開始した場合、IDLE は単一のプロセス内で動作し、RPC Python 実行サーバを走らせるサブプロセスを作りません。これは、プラットフォーム上で Python がサブプロセスや RPC ソケットインターフェイスを作れない場合に有用かもしれません。ただし、このモードではユーザコードが IDLE 自身から隔離されませんし、Run/Run Module (F5) 選択時に環境が再起動されてまっさらな状態になることもありません。コードを変更した場合、影響するモジュールを reload() しないといけませんし、変更を反映するには、すべての特定の項目 (from foo import baz など) を再インポートしないといけません。これらの理由から、可能なら常にデフォルトのサブプロセスを起こすモードで IDLE を起動するのが吉です。

バージョン 3.4 で非推奨.


Help sources

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.

Help menu entry "Python Docs" opens the extensive sources of help, including tutorials, available at, 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.

Selected URLs can be added or removed from the help menu at any time using the General tab of the Configure IDLE dialog.

Setting preferences [お好み設定]

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.

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.

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.

IDLE on macOS

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.

Extensions [拡張]

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.