python3 shell 中添加清屏

在windows中：

　　安装目录 \Lib(  D:\Python37\Lib) 中添加 ClearWindow.py 文件，文件内容：

"""

Clear Window Extension

Version: 0.2

Author: Roger D. Serwy

        roger.serwy@gmail.com

Date: 2009-06-14

It provides "Clear Shell Window" under "Options"

with ability to undo.

Add these lines to config-extensions.def

[ClearWindow]

enable=1

enable_editor=0

enable_shell=1

[ClearWindow_cfgBindings]

clear-window=<Control-Key-l>

"""

class ClearWindow:

    menudefs = [

        ('options', [None,

               ('Clear Shell Window', '<<clear-window>>'),

       ]),]

    def __init__(self, editwin):

        self.editwin = editwin

        self.text = self.editwin.text

        self.text.bind("<<clear-window>>", self.clear_window2)

        self.text.bind("<<undo>>", self.undo_event)  # add="+" doesn't work

    def undo_event(self, event):

        text = self.text

        text.mark_set("iomark2", "iomark")

        text.mark_set("insert2", "insert")

        self.editwin.undo.undo_event(event)

        # fix iomark and insert

        text.mark_set("iomark", "iomark2")

        text.mark_set("insert", "insert2")

        text.mark_unset("iomark2")

        text.mark_unset("insert2")

    def clear_window2(self, event): # Alternative method

        # work around the ModifiedUndoDelegator

        text = self.text

        text.undo_block_start()

        text.mark_set("iomark2", "iomark")

        text.mark_set("iomark", 1.0)

        text.delete(1.0, "iomark2 linestart")

        text.mark_set("iomark", "iomark2")

        text.mark_unset("iomark2")

        text.undo_block_stop()

        if self.text.compare('insert', '<', 'iomark'):

            self.text.mark_set('insert', 'end-1c')

        self.editwin.set_line_and_column()

    def clear_window(self, event):

        # remove undo delegator

        undo = self.editwin.undo

        self.editwin.per.removefilter(undo)

        # clear the window, but preserve current command

        self.text.delete(1.0, "iomark linestart")

        if self.text.compare('insert', '<', 'iomark'):

            self.text.mark_set('insert', 'end-1c')

        self.editwin.set_line_and_column()

        # restore undo delegator

        self.editwin.per.insertfilter(undo)

复制文件 ClearWindow.py 文件 到 D:\Python37\Lib\idlelib 目录中，在当前目录下有 config-extensions.def ，在文件末添加代码：

[ClearWindow]
enable=1
enable_editor=0
enable_shell=1
[ClearWindow_cfgBindings]
clear-window=<Control-Key-;>