python re

import re
#	Compile a regular expression pattern into a regular expression object, which can be used for matching using its match(), search() and other methods, described below.

prog = re.compile(pattern)
result = prog.match(string)

#	is equivalent to

result = re.match(pattern, string)

#re findall
>>> import re  
# A sample text string where regular expression is searched.  
>>> string = """Hello my Number is 123456789 and  
             my friend's number is 987654321"""
    
# A sample regular expression to find only digits.  
>>> regex = '\d+'             
    
>>> match = re.findall(regex, string)  
>>> print(match) 
['123456789', '987654321']

import re

# The string you want to find a pattern within
test_string = 'Hello greppers!'

# Creating a regular expression pattern
# This is a simple one which finds "Hello"
pattern = re.compile(r'Hello')

# This locates and returns all the occurences of the pattern
# within the test_string
match = pattern.finditer(test_string)

# Outputs all the ocurrences which were returned as 
# as match objects
for match in matches:
  print(match)

import re

pattern = '^a...s$'
test_string = 'abyss'
result = re.match(pattern, test_string)

if result:
  print("Search successful.")
else:
  print("Search unsuccessful.")	

import re
>>> m = re.search('(?<=abc)def', 'abcdef')
>>> m.group(0)
'def'

import re

result = re.sub(pattern, repl, string, count=0, flags=0);

>>> import re
>>> m = re.search('(?<=abc)def', 'abcdef')
>>> m.group(0)
'def'

  ## Search for pattern 'bb' in string 'aabbcc'.
  ## All of the pattern must match, but it may appear anywhere.
  ## On success, match.group() is matched text.
  match = re.search(r'bb', 'aabbcc') # found, match.group() == "bb"
  match = re.search(r'cd', 'aabbcc') # not found, match == None

  ## . = any char but \n
  match = re.search(r'...c', 'aabbcc') # found, match.group() == "abbc"

  ## \d = digit char, \w = word char
  match = re.search(r'\d\d\d', 'p123g') # found, match.group() == "123"
  match = re.search(r'\w\w\w', '@@abcd!!') # found, match.group() == "abc"

>>> m = re.search(r'(?<=-)\w+', 'spam-egg')
>>> m.group(0)
'egg'

parse("Today is Dec 1 16", fuzzy_with_tokens=True)
 
parse("Today is Dec 1 14", fuzzy_with_tokens=True)
 
parse("Today is Nov 30 12", fuzzy_with_tokens=True)

from dateutil.parser import parse
 
parse("Today is 12-01-18", fuzzy_with_tokens=True)