Extracting year from string in python

Question

How can I parse the foll. in python to extract the year:

'years since 1250-01-01 0:0:0'

The answer should be 1250

Answer 1

There are all sorts of ways to do it, here are several options:

• dateutil parser in a "fuzzy" mode:

  In [1]: s = 'years since 1250-01-01 0:0:0'
  
  In [2]: from dateutil.parser import parse
  
  In [3]: parse(s, fuzzy=True).year  # resulting year would be an integer
  Out[3]: 1250
  

• regular expressions with a capturing group:

  In [2]: import re
  
  In [3]: re.search(r"years since (\d{4})", s).group(1)
  Out[3]: '1250'
  

• splitting by "since" and then by a dash:

  In [2]: s.split("since", 1)[1].split("-", 1)[0].strip()
  Out[2]: '1250'
  

• or may be even splitting by the first dash and slicing the first substring:

  In [2]: s.split("-", 1)[0][-4:]
  Out[2]: '1250'
  

The last two involve more "moving parts" and might not be applicable depending on possible variations of the input string.