环境
- windows 11 64bit
- 2to3
简介
Python2 和 Python3 在语法和某些模块的使用上是有一些差别的，对于一些用 python2 编写的历史项目，要重新启用它们，2to3 是一个不错的转换工具，也是官方提供的工具，不需要安装，可靠性也比较高，它读取 Python 2.x 源代码并应用一系列修复程序将其转换为有效的 Python 3.x 代码。
实操
可以在终端中查看命令支持的所有参数
(base) PS C:\Users\xgx> 2to3.exe -h
Usage: 2to3 [options] file|dir ...
Options:
-h, --help show this help message and exit
-d, --doctests_only Fix up doctests only
-f FIX, --fix=FIX Each FIX specifies a transformation; default: all
-j PROCESSES, --processes=PROCESSES
Run 2to3 concurrently
-x NOFIX, --nofix=NOFIX
Prevent a transformation from being run
-l, --list-fixes List available transformations
-p, --print-function Modify the grammar so that print() is a function
-e, --exec-function Modify the grammar so that exec() is a function
-v, --verbose More verbose logging
--no-diffs Don't show diffs of the refactoring
-w, --write Write back modified files
-n, --nobackups Don't write backups for modified files
-o OUTPUT_DIR, --output-dir=OUTPUT_DIR
Put output files in this directory instead of
overwriting the input files. Requires -n.
-W, --write-unchanged-files
Also write files even if no changes were required
(useful with --output-dir); implies -w.
--add-suffix=ADD_SUFFIX
Append this string to all output filenames. Requires
-n if non-empty. ex: --add-suffix='3' will generate
.py3 files.下面看一个具体的示例，这是 python2 编写的代码，保存成文件 test.py
def greet(name):
print "Hello, {0}!".format(name)
print "What's your name?"
name = raw_input()
greet(name)执行转换命令
2to3.exe -w test.py可以看到，转换过程中会输出2个版本的差异，然后将转换后的内容写入原文件中(即覆盖)，而原文件内容会存放在 test.py.bak 中进行备份
(base) PS C:\Users\xgx\Desktop> 2to3.exe -w test.py
RefactoringTool: Skipping optional fixer: buffer
RefactoringTool: Skipping optional fixer: idioms
RefactoringTool: Skipping optional fixer: set_literal
RefactoringTool: Skipping optional fixer: ws_comma
RefactoringTool: Refactored test.py
--- test.py (original)
+++ test.py (refactored)
@@ -1,5 +1,5 @@
def greet(name):
- print "Hello, {0}!".format(name)
-print "What's your name?"
-name = raw_input()
+ print("Hello, {0}!".format(name))
+print("What's your name?")
+name = input()
greet(name)
RefactoringTool: Files that were modified:
RefactoringTool: test.py如果是文件夹批量转换，命令直接跟上源码文件夹即可，如
2to3.exe -w D:\project指定输出文件夹，使用 -o 参数；不想要 python2 的备份，使用 -n 参数
