25.5. IDLE
Source code: Lib/idlelib/
IDLE is Python’s Integrated Development and Learning Environment.
IDLE has the following features:
- coded in 100% pure Python, using the
tkinter
GUI toolkit - cross-platform: works mostly the same on Windows, Unix, and Mac OS X
- Python shell window (interactive interpreter) with colorizing of code input, output, and error messages
- multi-window text editor with multiple undo, Python colorizing, smart indent, call tips, auto completion, and other features
- search within any window, replace within editor windows, and search through multiple files (grep)
- debugger with persistent breakpoints, stepping, and viewing of global and local namespaces
- configuration, browsers, and other dialogs
25.5.3. Startup and code execution
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. Command line usage
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 combinatios 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)
If there are arguments:
- If
-
,-c
, orr
is used, all arguments are placed insys.argv[1:...]
andsys.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. IDLE-console differences
As much as possible, the result of executing Python code with IDLE is the
same as executing the same code in a console window. However, the different
interface and operation occasionally affects visible results. For instance,
sys.modules
starts with more entries.
IDLE also replaces sys.stdin
, sys.stdout
, and sys.stderr
with
objects that get input from and send output to the Shell window.
When this window 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. If sys
is reset with importlib.reload(sys)
,
IDLE’s changes are lost and things li ke input
, raw_input
, and
print
will not work correctly.
With IDLE’s Shell, one enters, edits, and recalls complete statements. Some consoles only work with a single physical line at a time.
25.5.3.3. Running without a subprocess
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 connecton 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.
Deprecated since version 3.4.
25.5.4. Help and preferences
25.5.4.1. Additional help sources
IDLE includes a help menu entry called “Python Docs” that will open the extensive sources of help, including tutorials, available at docs.python.org. Selected URLs can be added or removed from the help menu at any time using the Configure IDLE dialog. See the IDLE help option in the help menu of IDLE for more information.
25.5.4.2. Setting preferences
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. Extensions
IDLE contains an extension facility. Peferences for extensions can be changed with Configure Extensions. See the beginning of config-extensions.def in the idlelib directory for further information. The default extensions are currently:
- FormatParagraph
- AutoExpand
- ZoomHeight
- ScriptBinding
- CallTips
- ParenMatch
- AutoComplete
- CodeContext
- RstripExtension