CODEWITHSUNDEEP
pythonregex
cyrus24
cyrus24

Reputation: 363

Regular expressions for pattern matching time format in python

I am looking to match following time formats using regular expressions in python and mark True or False whenever the match is found/ not found in a line. Sample text as below. How can I achieve this task using only regular expressions?

One can observe '_am - _pm' and '_am-_pm' patterns that are consistent in every notation.The colons and number format with spaces matching is what I have been attempting to do. below is what I found from here

HH:MM 12-hour format, optional leading 0, mandatory meridiems (AM/PM)
/((1[0-2]|0?[1-9]):([0-5][0-9]) ?([AaPp][Mm]))/

Sample text:

Lorem Ipsum is dummy text of the printing and typesetting industry between 2am-8pm. 
Contrary to popular belief, Lorem Ipsum is not simply random text. : False
Lorem has been the industry between 2:00am - 8:00pm standard dummy text since the 1500s. 
It has survived not only five centuries, but also between 08:00am-05:00pm 
It was popularised from 5:30am - 8:59pm with the release of Letraset sheets. 
More recently with desktop publishing software like Aldus PageMaker 983-765-0976.

Desired output:

Lorem Ipsum is dummy text of the printing and typesetting industry between 2am-8pm. : True
Contrary to popular belief, Lorem Ipsum is not simply random text. : False
Lorem has been the industry between 2:00am - 8:00pm standard dummy text since the 1500s. : True
It has survived not only five centuries, but also between 08:00am-05:00pm : True
It was popularised from 5:30am - 8:59pm with the release of Letraset sheets. : True
More recently with desktop publishing software like Aldus PageMaker 983-765-0976. : False

Upvotes: 2

Views: 642

Answers (1)

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 626699

You may use

(?i)(?<!\d)(?:1[0-2]|0?[1-9])(?::(?:[0-5][0-9]))?\s?[ap]m\s*-\s*(?:1[0-2]|0?[1-9])(?::(?:[0-5][0-9]))?\s?[ap]m\b

See the regex demo

Details

  • (?i) - case insensitive mode on
  • (?<!\d) - no digit before is allowed
  • (?:1[0-2]|0?[1-9])(?::(?:[0-5][0-9]))? - time pattern:
    • (?:1[0-2]|0?[1-9]) - 0 to 12 with an optional leading 0 before 1-9 digits
    • (?::(?:[0-5][0-9]))? - an optional minut sequence with : separator
  • \s? - an optional whitespace
  • [ap]m - a or p and then m
  • \s*-\s* - a hyphen enclosed with 0+ whitespaces
  • (?:1[0-2]|0?[1-9])(?::(?:[0-5][0-9]))?\s?[ap]m - the same time pattern as above
  • \b - word boundary.

Python demo:

import re
time = r'(?:1[0-2]|0?[1-9])(?::(?:[0-5][0-9]))?\s?[ap]m'
pattern = re.compile(r'(?i)(?<!\d){0}\s*-\s*{0}\b'.format(time))
texts = ['Lorem Ipsum is dummy text of the printing and typesetting industry between 2am-8pm.',
'Contrary to popular belief, Lorem Ipsum is not simply random text.',
'Lorem has been the industry between 2:00am - 8:00pm standard dummy text since the 1500s.',
'It has survived not only five centuries, but also between 08:00am-05:00pm',
'It was popularised from 5:30am - 8:59pm with the release of Letraset sheets.',
'More recently with desktop publishing software like Aldus PageMaker 983-765-0976.']
for text in texts:
    print (text, bool(pattern.search(text)), sep=" : ")

Output:

Lorem Ipsum is dummy text of the printing and typesetting industry between 2am-8pm. : True
Contrary to popular belief, Lorem Ipsum is not simply random text. : False
Lorem has been the industry between 2:00am - 8:00pm standard dummy text since the 1500s. : True
It has survived not only five centuries, but also between 08:00am-05:00pm : True
It was popularised from 5:30am - 8:59pm with the release of Letraset sheets. : True
More recently with desktop publishing software like Aldus PageMaker 983-765-0976. : False

Upvotes: 2

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