使用子正则表达式调用删除最后一个字符

Question

尝试删除每行的最后一个“，”，但当前逻辑只删除最后一个：

import re

x = """
A,B,C,
1,2,3,
4,5,6,
7,8,9,
"""
x = re.sub(",$","",x,re.MULTILINE)
print(x)

Output：

A,B,C,
1,2,3,
4,5,6,
7,8,9

预期 output：

A,B,C
1,2,3
4,5,6
7,8,9

Answer 1

re.sub(regex, subst, test_str, 0, re.MULTILINE)

flag 是第 5 个参数。

Answer 2

这应该这样做：

import re

x = """
A,B,C,
1,2,3,
4,5,6,
7,8,9,
"""
# regix to remove all commas at the end of each line
x = re.sub(r',$', '', x, flags=re.M)
# '$', means the end of the line
# '', means replace with nothing
# x, os the string to be searched
# flags=re.M, means to search the whole string, not just the first line
# flags=re.MULTILINE does the same job
print(x)

输出->

A,B,C
1,2,3
4,5,6
7,8,9