在 Python 中使用正则表达式在匹配模式后打印三行

Question

Dear python community,

I want to print three lines after matching pattern in python (printing the matching line is easy, eg by using re.match(r'(. )match(. )', pattern)).

How to do it in python? The equivalent operation can be performed using "grep -A3 "pattern" filename".

Answer 1

Assuming you are iterating over the lines, I would use something like this

i = 0
for line in lines:
    if re.match(pattern, line):
        i = 4
    if i > 0:
        print line
        i -= 1