读以数字开头的行

Question

在python中，我怎么能只读取以数字开头的行呢

Hello World <--ignore
Lovely day
blah43 
blah
1234 <--read
blah12 <--ignore
blah 
3124 <--read
Not matter how many words there are <--ignore
blah 
0832 8423984 234892304 8239048324 8023948<--read
blah132 <--ignore

Answer 1

您可以使用^{}函数：

for line in open('f.txt','r'):
   if line[0].isdigit():
       print line

Answer 2

import re
with open("filename") as f:
    for line in f:
        if re.match(r"^\d+.*$",line):
            print line