How do you write a regex in python which picks out all strings beginning with a specific number

Question

I'm trying to get this regex to pick out both 7gh and 7ui but I can only get it to pick out the first one. If anyone knows how to amend the regex such that it also picks out 7ui, I would seriously appreciate it. I should also point out that I mean strings separated by a space.

b = re.search(r'^7\w+','7gh ghj 7ui')
c = b.group()

What about a7b? Both solutions would currently pick it as 7b - is that correct? — Sebastian Proske
– Sebastian Proske, Commented Jul 31, 2017 at 8:46

akash karothiya · Accepted Answer · 2017-07-31 08:43:49Z

2

Remove ^ and use findall() :

>>> re.findall(r'7\w+','7gh ghj 7ui')
['7gh', '7ui']

answered Jul 31, 2017 at 8:43

akash karothiya

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1 Comment

bobsmith76 Over a year ago

that doesn't work. That only captures the first string with 7

Graham · Accepted Answer · 2017-09-23 18:15:34Z

1

You need to remove ^ (start of string anchor) and use re.findall to find all non-overlapping matches of pattern in string:

import re
res = re.findall(r'7\w+','7gh ghj 7ui')
print(res)

See the Python demo

If you need to get these substrings as whole words, enclose the pattern with a word boundary, \b:

res = re.findall(r'\b7\w+\b','7gh ghj 7ui')

edited Sep 23, 2017 at 18:15

Graham

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answered Jul 31, 2017 at 8:43

Wiktor Stribiżew

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5 Comments

akash karothiya Over a year ago

difference of few sec :)

Jon Clements Over a year ago

They probably want a word boundary in there to avoid picking up bob7something...

Wiktor Stribiżew Over a year ago

@akashkarothiya Yeah, but I think OP might need further tweaking, so, I also suggest a word boundary.

akash karothiya Over a year ago

@WiktorStribiżew much appreciated :) helpful

akash karothiya Over a year ago

@bobsmith76 you should also consider Wikter's 2nd method for future reference, using \b, Please see

Sayse · Accepted Answer · 2017-07-31 08:49:34Z

0

You may find it easier to just not use regex

[s for s in my_string.split() if s.startswith('7')]

answered Jul 31, 2017 at 8:49

Sayse

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1 Comment

bobsmith76 Over a year ago

No, I'm trying to understand how regexes work. I'm not trying to get something done.

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