如何从文本文件中提取特定的目标编号

Question

从文本文件输入

mpls switch-l2vc 10.123.150.98 205131102 tunnel-policy TE between 10.123.130.1 
mpls switch-l2vc 10.123.150.100 213131302 tunnel-policy TE between 10.123.130.1 
mpls switch-l2vc 10.123.149.52 205129302 tunnel-policy TE between 10.123.130.1 
mpls switch-l2vc 10.123.149.50 205129102 tunnel-policy TE between 10.123.130.1
mpls switch-l2vc 10.123.159.38 212134501 tunnel-policy TE between 10.123.130.1 
mpls switch-l2vc 10.123.150.99 205131202 tunnel-policy TE between 10.123.130.1 
mpls switch-l2vc 10.123.150.99 205131212 tunnel-policy TE between 10.123.130.1 

期待成功（只保留开始“205”）

mpls switch-l2vc 10.123.150.98 205131102 tunnel-policy TE between 10.123.130.1 
mpls switch-l2vc 10.123.149.52 205129302 tunnel-policy TE between 10.123.130.1 
mpls switch-l2vc 10.123.149.50 205129102 tunnel-policy TE between 10.123.130.1
mpls switch-l2vc 10.123.150.99 205131202 tunnel-policy TE between 10.123.130.1 
mpls switch-l2vc 10.123.150.99 205131212 tunnel-policy TE between 10.123.130.1

从expect output：我更喜欢在第四行的第四个边界文本中选择包含编号为“205”的行

Answer 1

我们可以使用re.search尝试正则表达式方法：

with open('input.txt') as f:
    lines = f.readlines()

for line in lines:
    if re.search(r'^\S+ \S+ \S+ 205\d+.*$', line, re.M):
        print(line)