Python Regex expression

Question

Trying to write a Regex expression in Python to match strings.

I want to match input that starts as first, first?21313 but not first.

So basically, I don't want to match to anything that has . the period character.

I've tried word.startswith(('first[^.]?+')) but that doesn't work. I've also tried word.startswith(('first.?+')) but that hasn't worked either. Pretty stumped here

str.startswith() takes literals - not regular expressions... look into importing and using the actual re and its .match method... — Jon Clements
– Jon Clements, Commented May 8, 2015 at 23:36

idelcano · Accepted Answer · 2015-05-08 23:58:46Z

1

 import re  
 def check(word):
        regexp = re.compile('^first([^\..])+$')
        return regexp.match(word)

And if you dont want the dot: ^first([^..])+$ (first + allcharacter except dot and first cant be alone).

edited May 8, 2015 at 23:58

answered May 8, 2015 at 23:39

idelcano

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2 Comments

simplycoding Over a year ago

How do I do this with startswith? When I tried, it gave me issues?

idelcano Over a year ago

why do you want do it with startswith?, if you have a lot of checks and you want do it in only one line, you can create method like: check(word,regexpParam) and re.compile(refexpParam) and you change: word.startswith(('first[^.]?+')) for check(word,'^first([^\..])+$')

Shashank · Accepted Answer · 2015-05-09 00:15:09Z

0

You really don't need regex for this at all.

word.startswith('first') and word.find('.') == -1

But if you really want to take the regex route:

>>> import re
>>> re.match(r'first[^.]*$', 'first')
<_sre.SRE_Match object; span=(0, 5), match='first'>
>>> re.match(r'first[^.]*$', 'first.') is None
True

edited May 9, 2015 at 0:15

answered May 9, 2015 at 0:12

Shashank

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2 Comments

simplycoding Over a year ago

There are a lot of edge cases and allowable values, first.stuffafter being one. So that definitely won't work EDIT: didn't see your edit in time. Looks like the other answer and I'll try testing

Shashank Over a year ago

@simplycoding What output are you expecting from first.stuffafter? Do you expect a list in the form of ['first', 'stuffafter']? Do you expect two capture groups from the match that contains the text?

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