i am trying to extract date from text using regular expression

Question

I am trying to extract the date from this '2025-03-21T12:54:41Z' text using python regular expression.

date=re.match('(\d{4})[/.-](\d{2})[/.-](\d{2})$', date[0])
print(date)

This give output as None

also, I tried this code

date_reg_exp = re.compile('\d{4}(?P<sep>[-/])\d{2}(?P=sep)\d{2}')
matches_list=date_reg_exp.findall(date[0])
for match in matches_list:
  print match

This gives output as - only

Please help

You should use `datetime.datetime.strptime` to parse instead of regex — Hai Vu, Apr 07 '18 at 16:54
Your first one won't work because you used `$`, which means the end of the string. And the second, you're only grouping on and printing the separators — OneCricketeer, Apr 07 '18 at 16:56
As @cricket_007 said, $ matches the end. If you want to match the beginning, use ^ instead: date= re.match('^(\d{4})[/.-](\d{2})[/.-](\d{2})', date[0]) — Camila Burne, Apr 07 '18 at 16:59
@Hai Vu already tried datetime.datetime.strptime but it is not working — Ujjwal Pawar, Apr 07 '18 at 16:59
@cricket_007 thanks man it worked.I had no idea that so many standards exist to store time. — Ujjwal Pawar, Apr 07 '18 at 17:05
Welcome, but honestly, what's wrong with `date[0].split("T")[0]`? — OneCricketeer, Apr 07 '18 at 17:06

Sweeper · Answer 1 · 2018-04-07T17:05:32.720

0

Your regular expression is wrong because it has a $ at the end. $ asserts that this is the end of the string.

The regex engine matches your string with the regex and after matching the last two digits, expects a $ - end of the string. However, your string still has T12:54:41Z before the end, so the regex does not match.

To fix this, remove $:

>>> re.match('(\d{4})[/.-](\d{2})[/.-](\d{2})', '2025-03-21T12:54:41Z')
<_sre.SRE_Match object; span=(0, 10), match='2025-03-21'>

edited Apr 07 '18 at 17:05

answered Apr 07 '18 at 16:59

Sweeper

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strptime doesn't work as expected. See marked duplicate in comments – OneCricketeer Apr 07 '18 at 17:04
@cricket_007 Got it. Deleted now. – Sweeper Apr 07 '18 at 17:05

score 0 · Answer 2 · answered Apr 07 '18 at 17:19

Instead of using $ sigil at the end of your regexp, which is matching end-of-line character, try using ^ at the beginning:

import re
date='2025-03-21T12:54:41Z'
date=re.match('^(\d{4})[/.-](\d{2})[/.-](\d{2})', date)
print(date)

Output in python3:

<_sre.SRE_Match object; span=(0, 10), match='2025-03-21'>

Python2:

<_sre.SRE_Match object at 0x7fd191ac1ae0>

i am trying to extract date from text using regular expression

2 Answers2