# 25.5. IDLE

源代码： Lib/idlelib/

IDLE 是 Python 所内置的开发与学习环境。

IDLE 具有以下特性：

- 编码于 100% 纯正的 Python，使用名为 `tkinter` 的图形用户界面工具

- 跨平台：在 Windows、Unix 和 macOS 上工作近似。

- 提供输入输出高亮和错误信息的 Python 命令行窗口 （交互解释器）

- 提供多次撤销操作、Python 语法高亮、智能缩进、函数调用提示、自动补全等功能的多窗口文本编辑器

- 在多个窗口中检索，在编辑器中替换文本，以及在多个文件中检索（通过 grep）

- 提供持久保存的断点调试、单步调试、查看本地和全局命名空间功能的调试器

- 配置、浏览以及其它对话框

## 25.5.1. 目录

IDEL 具有两个主要窗口类型，分别是命令行窗口和编辑器窗口。用户可以同时打开多个编辑器窗口。对于 Windows 和 Linux 平台，都有各自的主菜单。如下记录的每个菜单标识着与之关联的窗口类型。

导出窗口，例如使用 编辑=>在文件中查找 是编辑器窗口的的一个子类型。它们目前有着相同的主菜单，但是默认标题和上下文菜单不同。

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 guidlines.

### 25.5.1.1. 文件目录 （命令行和编辑器）

新建文件

  创建一个文件编辑器窗口。

打开…

  使用打开窗口以打开一个已存在的文件。

近期文件

  打开一个近期文件列表，选取一个以打开它。

打开模块…

  打开一个已存在的模块 （搜索 sys.path）

类浏览器

  于当前所编辑的文件中使用树形结构展示函数、类以及方法。在命令行中，首先打开一个模块。

路径浏览

  在树状结构中展示 sys.path 目录、模块、函数、类和方法。

保存

  如果文件已经存在，则将当前窗口保存至对应的文件。自打开或上次保存之后经过修改的文件的窗口标题栏首尾将出现星号 * 。如果没有对应的文件，则使用“另存为”代替。

保存为…

  使用“保存为”对话框保存当前窗口。被保存的文件将作为当前窗口新的对应文件。

另存为副本…

  保存当前窗口至另一个文件，而不修改当前对应文件。

打印窗口

  通过默认打印机打印当前窗口。

关闭

  关闭当前窗口（如果未保存则询问）。

退出

  关闭所有窗口并退出 IDLE（如果未保存则询问）

### 25.5.1.2. 编辑目录（命令行和编辑器）

撤销操作

  撤销当前窗口的最近一次操作。最高可以撤回 1000 条操作记录。

重做

  重做当前窗口最近一次所撤销的操作。

剪切

  复制选区至系统剪贴板，然后删除选区。

复制

  复制选区至系统剪贴板。

粘贴

  插入系统剪贴板的内容至当前窗口。

剪贴板功能也可用于上下文目录。

全选

  选择当前窗口的全部内容。

查找…

  打开一个提供多选项的查找窗口。

再次查找

  重复上次搜索，如果结果存在。

查找选区

  查找当前选中的字符串，如果存在

在文件中查找…

  打开文件查找对话框。将结果输出至新的输出窗口。

替换…

  打开 查找并替换 对话框。

前往行

  Move cursor to the line number requested and make that line visible.

提示完成

  Open a scrollable list allowing selection of keywords and attributes. See Completions in the Tips sections below.

展开文本

  展开键入的前缀以匹配同一窗口中的完整单词；重复以获得不同的扩展。

显示调用贴士

  After an unclosed parenthesis for a function, open a small window with function parameter hints.

显示周围括号

  突出显示周围的括号。

### 25.5.1.3. 格式菜单（仅 window 编辑器）

缩进区域

  将选定的行右移缩进宽度（默认为4个空格）。

区域减少缩进

  将选定的行向左移动缩进宽度（默认为4个空格）。

区域注释

  在所选行的前面插入 ##。

区域取消注释

  从所选行中删除开头的 ＃ 或 ##。

区域添加制表符

  将 前导 空格变成制表符。 （注意：我们建议使用4个空格来缩进Python代码。）

区域取消制表符

  将 所有 制表符转换为正确的空格数。

切换标签

  打开一个对话框，以在缩进和空格之间切换。

新缩进宽度

  打开一个对话框以更改缩进宽度。 Python社区接受的默认值为4个空格。

格式段落

  在注释块或多行字符串或字符串中的选定行中，重新格式化当前以空行分隔的段落。段落中的所有行的格式都将少于N列，其中N默认为72。

尾随空格

  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.

### 25.5.1.4. 运行菜单（仅 window 编辑器）

Python Shell

  打开或唤醒Python Shell窗口。

检查模块

  检查 “编辑器” 窗口中当前打开的模块的语法。如果尚未保存该模块，则 IDLE会提示用户保存或自动保存，如在 “空闲设置” 对话框的 “常规” 选项卡中所选择的那样。如果存在语法错误，则会在 “编辑器” 窗口中指示大概位置。

运行模块

  Do Check Module (above). 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 `print` or `write`. 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 `python -i file` at a command line.

### 25.5.1.5. Shell 菜单（仅 window 编辑器）

查看最近重启

  将Shell窗口滚动到上一次Shell重启。

重启Shell

  重新启动shell 以清理环境。

中断执行

  停止正在运行的程序。

### 25.5.1.6. 调试菜单（仅 window 编辑器）

跳转到文件/行

  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.

调试器（切换）

  激活后，在Shell中输入的代码或从编辑器中运行的代码将在调试器下运行。在编辑器中，可以使用上下文菜单设置断点。此功能不完整，具有实验性。

堆栈查看器

  在树状目录中显示最后一个异常的堆栈回溯，可以访问本地和全局。

自动打开堆栈查看器

  在未处理的异常上切换自动打开堆栈查看器。

### 25.5.1.7. 选项菜单（命令行和编辑器）

配置 IDLE

  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 (see below). On macOS, open the configuration dialog by selecting Preferences in the application menu. To use a new built-in color theme (IDLE Dark) with older IDLEs, save it as a new custom theme.

  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.

Code Context (toggle)(Editor Window only)

  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. Clicking a line in this pane exposes that line at the top of the editor.

### 25.5.1.8. Window 菜单（命令行和编辑器）

Zoom Height

  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 rest of this menu lists the names of all open windows; select one to bring it to the foreground (deiconifying it if necessary).

### 25.5.1.9. 帮助菜单（命令行和编辑器）

关于 IDLE

  显示版本，版权，许可证，荣誉等。

IDLE 帮助

  显示此 IDLE 文档，详细介绍菜单选项，基本编辑和导航以及其他技巧。

Python 文档

  访问本地Python文档（如果已安装），或启动Web浏览器并打开docs.python.org显示最新的Python文档。

海龟演示

  Run the turtledemo module with example python code and turtle drawings.

Additional help sources may be added here with the Configure IDLE dialog under the General tab. See the “Help sources” subsection below for more on Help menu choices.

### 25.5.1.10. 上下文菜单

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.

剪切

  复制选区至系统剪贴板，然后删除选区。

复制

  复制选区至系统剪贴板。

粘贴

  插入系统剪贴板的内容至当前窗口。

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.

设置断点

  在当前行设置断点

清除断点

  清除当前行断点

shell 和输出窗口还具有以下内容。

跳转到文件/行

  与调试菜单相同。

The Shell window also has an output squeezing facility explained in the the Python Shell window subsection below.

压缩

  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.

## 25.5.2. 编辑和导航

### 25.5.2.1. 编辑窗口

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.

### 25.5.2.2. 按键绑定

在本节中，’C’ 是指 Windows 和 Unix 上的 `Control` 键，以及 macOS 上的 `Command` 键。

- `Backspace` 向左删除; `Del` 向右删除

- `C-Backspace` 向左删除单词; `C-Del` 向右删除单词

- 方向键和 `Page Up`/`Page Down` 移动

- `C-LeftArrow` 和 `C-RightArrow` 按字移动

- `Home`/`End` 跳转到行首/尾

- `C-Home`/`C-End` 跳转到文档首/尾

- 一些有用的Emacs绑定是从Tcl / Tk继承的：

  > - `C-a` 行首

  > - `C-e` 行尾

  > - `C-k` 删除行（但未将其放入剪贴板）

  > - `C-l` center window around the insertion point

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

  > - `C-f` go forward one character without deleting (usually you can also use the cursor key for this)

  > - `C-p` go up one line (usually you can also use the cursor key for this)

  > - `C-d` 删除下一个字符

Standard keybindings (like `C-c` to copy and `C-v` to paste) may work. Keybindings are selected in the Configure IDLE dialog.

### 25.5.2.3. 自动缩进

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 in the edit menu.

### 25.5.2.4. 完成

Completions are supplied for functions, classes, and attributes of classes, both built-in and user-defined. Completions are also provided for filenames.

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.

If there is only one possible completion for the characters entered, a `Tab` will supply that completion without opening the ACW.

‘Show Completions’ will force open a completions window, by default the `C-space` 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.

If a string of characters is typed, the ACW selection will jump to the entry most closely matching those characters. Entering a `tab` will cause the longest non-ambiguous match to be entered in the Editor window or Shell. Two `tab` 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.

“Hidden” attributes can be accessed by typing the beginning of hidden name after a ‘.’, e.g. ‘_’. This allows access to modules with `__all__` set, or to class-private attributes.

Completions and the ‘Expand Word’ facility can save a lot of typing!

Completions are currently limited to those in the namespaces. Names in an Editor window which are not via `__main__` and `sys.modules` 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.

If you don’t like the ACW popping up unbidden, simply make the delay longer or disable the extension.

### 25.5.2.5. 提示

A calltip is shown when one types `(` after the name of an accessible 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 `)` is typed. When the cursor is in the argument part of a definition, the menu or shortcut display a calltip.

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.

The set of accessible 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.

For example, restart the Shell and enter `itertools.count(`. A calltip appears because Idle imports itertools into the user process for its own use. (This could change.) Enter `turtle.write(` and nothing appears. Idle does not import turtle. The menu or shortcut do nothing either. Enter `import turtle` and then `turtle.write(` will work.

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.

### 25.5.2.6. Python Shell 窗口

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` 中断执行命令

- `C-d` sends end-of-file; closes window if typed at a `>>>` prompt

- `Alt-/` (Expand word) is also useful to reduce typing

  历史命令

  - `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` while on any previous command retrieves that command

### 25.5.2.7. 文本颜色

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 `class` and `def`, strings, and comments. For any text window, these are the cursor (when present), found text (when possible), and selected text.

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.

## 25.5.3. 启动和代码执行

Upon startup with the `-s` option, IDLE will execute the file referenced by the environment variables `IDLESTARTUP` or `PYTHONSTARTUP`. IDLE first checks for `IDLESTARTUP`; if `IDLESTARTUP` is present the file referenced is run. If `IDLESTARTUP` is not present, IDLE checks for `PYTHONSTARTUP`. 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.

In addition, `Tk` also loads a startup file if it is present. Note that the Tk file is loaded unconditionally. This additional file is `.Idle.py` 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.

### 25.5.3.1. 命令行语法

    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)

如果有参数：

- If `-`, `-c`, or `r` is used, all arguments are placed in `sys.argv[1:...]` and `sys.argv[0]` is set to `''`, `'-c'`, or `'-r'`. No editor window is opened, even if that is the default set in the Options dialog.

- Otherwise, arguments are files opened for editing and `sys.argv` reflects the arguments passed to IDLE itself.

### 25.5.3.2. 启动失败

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 random.py and tkinter.py. 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 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.

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.

If IDLE quits with no message, and it was not started from a console, try starting from a console (`python -m idlelib)` and see if a message appears.

### 25.5.3.3. 运行用户代码

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.

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.

### 25.5.3.4. Shell中的用户输出

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.

Text widgets display a subset of Unicode, the Basic Multilingual Plane (BMP). Which characters get a proper glyph instead of a replacement box depends on the operating system and installed fonts. Newline characters cause following text to appear on a new line, but other control characters are either replaced with a box or deleted. However, `repr()`, which is used for interactive echo of expression values, replaces control characters, some BMP codepoints, and all non-BMP characters with escape codes before they are output.

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.

### 25.5.3.5. 开发 tkinter 应用程序

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 milleseconds. 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.

### 25.5.3.6. 在没有子进程的情况下运行

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.

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.

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.

3.4 版后已移除.

## 25.5.4. 帮助和偏好

### 25.5.4.1. 帮助资源

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 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.

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

### 25.5.4.2. 偏好设定

The font preferences, highlighting, keys, and general preferences can be changed via Configure IDLE on the Option menu. Keys can be user defined; IDLE ships with four built-in key sets. In addition, a user can create a custom key set in the Configure IDLE dialog under the keys tab.

### 25.5.4.3. macOS 上的IDLE

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.

### 25.5.4.4. 扩展

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.