转换Python2 -> Python3

藉由python35\Tools\scripts\2to3.py 档转换

python D:\python\Tools\scripts\2to3.py D:\Users\a0979\Desktop\scrip.py

python [转档程式] [欲转档.py]
* python 为 python3 ->因为转档程式为python3

![](https://i.imgur.com/PeQkvhk.png)

python2-scrip2.py

import httplib

i = 99999999L
print type(i)

try:
	print 5/2

except ValueError, e:
	print "Value Error Detected! "

j = 10
print j
print [j for j in range(15)]
print j

python3-scrip.py

import http.client

i = 99999999
print(type(i))

try:
	print(5/2)

except ValueError as e:
	print("Value Error Detected! ")	

j = 10
print (j)
print ([j for j in range(15)])
print (j)

差别

1. 语法差异

   1. import 函式库上httplib 在python3中被取代为http.client                                

   2. print 上python3要求使用者将参数加上()号                                                                  

   3. try-except 将原本的,改为as                                        

2. 语意差异

   1. python3 无long长整数->int

i = 99999999L
print type(i)

#python2 -> <type 'long'>
#python3 -> <class 'int'>

2.python3 自动化为浮点数

print 5/2

#python2 -> 2
#python3 -> 2.5

Linux中Python2.x 转换Python3.x

• 使用2to3指令

2to3 [python2专案]

下载Python3

wget https://www.python.org/ftp/python/3.2/Python-3.2.tar.bz2
tar -xvjf Python-3.2.tar.bz2 -C /opt #解壓縮到 /opt
cd /opt/Python-3.2
./configure
make
make install

使用2to3转档

2to3 -w script.py

#会产生一个script.py -> Python3 script.py.bak -> Python2

• 执行程式码

cp script.py.bak script2.py
python script2.py
python3 script.py

结果与windows相同