Python re.findall returning only first character

Question

Working in Python 3.6, I have a list of html files with date prefixes. I'd like to return all dates, so I join the list and use some regex, like so:

import re
snapshots =  ['20180614_SII.html', '20180615_SII.html']
p = re.compile("(\d|^)\d*(?=_)")
snapshot_dates = p.findall(' '.join(snapshots))

snapshot_dates is a list, ['2', '2'], but I'm expecting ['20180614', '20180615']. Demonstration here: https://regexr.com/3r44o嵌入了无法显示的视频。我错过了什么？

Answer 1

您可以简化模式以使用 \ d + 而不是（\ d | ^）\ d * ：

＆＃xA;＆＃xA;

  p = re.compile（“\ d +（？= _）”）＆＃xA; print（p.findall（''。join（snapshots）））＆＃xA;＃['20180614' ，'20180615']＆＃xA;  

＆＃xA;＆＃xA;

但是，在这种情况下，您可能不需要 regex 来实现所需的结果。您只需将字符串拆分为 _ ：

＆＃xA;＆＃xA;

  print（[x.split（“_”）[0] for快照中的x]＆＃xA;＃['20180614'，'20180615']＆＃xA;  

＆＃xA;