【linux/windows】python2代碼轉python3-工具2to3

【linux/windows】python2代碼轉python3-工具2to3

儘管如今有不少項目基於python2開發，但愈來愈多的項目以python3開發，並且愈來愈多的包開始不支持python2，就拿ubuntu系列版原本說，ubuntu20.04源庫沒有python-pip，或者作web開發的django框架3.0來講，直接python3，但項目確定不可能直接重寫，幸運的是無論win系統仍是linux下都提供了對應的版本轉換工具，只需簡單執行相關命令，便可完成python2轉python3。

1.windows下轉換

在咱們安裝的python文件目錄下，最好在官網下載zip包，解壓後放置任何位置，同時設置環境變量，保證在命令行下運行python能夠運行，固然嫌麻煩也能夠下載那種一路next的版本，環境變量默認幫你設置好的。

假定上述工做你已完成的狀況下，接下來打開python的安裝目錄，好比如下是我本身的目錄及文件：

注意2to3.py，經過此文件就能夠完成版本轉換，下面是使用實例。

# 查看哪些是須要更改的
python 2to3.py test.py

# py2轉py3
python 2to3.py -w test.py

# 批量轉換或查看更改部分
python 2to3.py [-w] ./

2.linux下的轉換-ubuntu18.04

在ubuntu下，直接有這樣一個二進制的命令2to3，能夠直接運行這個命令更改相關代碼。

# 查看命令
root@ubuntu:~# ls -l  /usr/bin/ | grep 2to3
-rwxr-xr-x 1 root root           96 Feb 27 23:10 2to3-2.7

# 查看幫助
root@ubuntu:~# 2to3-2.7 --help
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
  -v, --verbose         More verbose logging
  --no-diffs            Don't show diffs of the refactoring
  -w, --write           Write back modified files # 使用後，後將文件轉換python3，同時多出後綴.bak的備份文件，python2版本
  -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.

# 查看須要更改處
root@ubuntu:~/test2to3# 2to3-2.7 pkg/p_demo.py.bak
RefactoringTool: Skipping optional fixer: buffer
RefactoringTool: Skipping optional fixer: idioms
RefactoringTool: Skipping optional fixer: set_literal
RefactoringTool: Skipping optional fixer: ws_comma
RefactoringTool: Refactored pkg/p_demo.py.bak
--- pkg/p_demo.py.bak   (original)
+++ pkg/p_demo.py.bak   (refactored)
@@ -1,2 +1,2 @@
 #!/usr/bin/python
-print "p_demo file"
+print("p_demo file")
RefactoringTool: Files that need to be modified:
RefactoringTool: pkg/p_demo.py.bak

# py2 -> py3
root@ubuntu:~/test2to3# 2to3-2.7 pkg/p_demo.py.bak -w
RefactoringTool: Skipping optional fixer: buffer
RefactoringTool: Skipping optional fixer: idioms
RefactoringTool: Skipping optional fixer: set_literal
RefactoringTool: Skipping optional fixer: ws_comma
RefactoringTool: Refactored pkg/p_demo.py.bak
--- pkg/p_demo.py.bak   (original)
+++ pkg/p_demo.py.bak   (refactored)
@@ -1,2 +1,2 @@
 #!/usr/bin/python
-print "p_demo file"
+print("p_demo file")
RefactoringTool: Files that were modified:
RefactoringTool: pkg/p_demo.py.bak

# 也能夠直接對目錄進行操做
root@ubuntu:~/test2to3# 2to3-2.7 [-w] ./
RefactoringTool: Skipping optional fixer: buffer
RefactoringTool: Skipping optional fixer: idioms
RefactoringTool: Skipping optional fixer: set_literal
RefactoringTool: Skipping optional fixer: ws_comma
RefactoringTool: No changes to ./pkg/p_demo.py
RefactoringTool: No changes to ./proj/pro_demo2.py
RefactoringTool: No changes to ./tools/t_demo3.py
RefactoringTool: Files that need to be modified:
RefactoringTool: ./pkg/p_demo.py
RefactoringTool: ./proj/pro_demo2.py
RefactoringTool: ./tools/t_demo3.py

以上是不一樣系統下使用2to3工具轉換python版本，但願對你有用。