python - 在 python 中使用 re.sub 进行字符串替换

Question

在学习 Python 正则表达式时，我想将所有 Python 2x 之类的打印函数替换为 Python 3x，例如使用 re.sub:

import re

with open("py2.py", "r") as f:
    matter = f.read()
mtr = re.sub(r"print\s+\"(.+)\"+",r"print(", matter)
with open("pr.py", "w") as f:
    final = f.write(mtr)

py2.py的内容是:

print "Anything goes here"
print "Anything" 
print "Something goes here" 

但是这段代码将 print "Anything goes here" 替换为 print(, How to capture whole string and replace last quote to ")"a well?

Answer 1

您想在您的搜索中使用对匹配组的引用:

re.sub(r'print\s+"(.*)"', r'print("\1")', matter)

用作:

>>> import re
>>> matter = """
... print "Anything goes here"
... print "Anything"
... print "Something goes here"
... """
>>> print(re.sub(r'print\s+"(.*)"', r'print("\1")', matter))

print("Anything goes here")
print("Anything")
print("Something goes here")

---

请注意，如果您的目标是将 python2 代码修改为与 python3 兼容，则 2to3 utility 已经存在它包含在 python 本身中。