Get a particular string after matching a string in regex python

Question

I am new python programming. I have been trying to find some data after matching a string using regex.

For example:

str1 = 'ethernet33 20628103568 111111 22222222222 '

I am only looking for '20628103568', however with my code, it is printing everything after ethernet33

Here is the code

match1 = re.search("(?<=ethernet33\s).*(?<=\s)", str1)
print match1.group()

output:

20628103568 111111 22222222222

expected output:

20628103568

Any guidance on how to modify the above regex to achieve this is would be much appreciated

Moinuddin Quadri · Accepted Answer · 2017-12-31 19:52:05Z

2

You should be using this regex instead:

>>> import re

#          to match only the digits with  v
#    your "positive lookbehind assertion" v
>>> match1 = re.search('(?<=^ethernet33\s)\d+', str1)
#                           ^ to just match the pattern at the start of string.
#                           ^ prevents additional traversals
>>> match1.group()
'20628103568'

edited Dec 31, 2017 at 19:52

answered Dec 31, 2017 at 19:47

Moinuddin Quadri

48.4k13 gold badges101 silver badges137 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

heemayl Over a year ago

Beat me to it :). FWIW, just str1.split()[1] would do in this case.

heemayl Over a year ago

Additionally, matching the start with ^ would save you further traversal: (?<=^ethernet33\s)\d+

Moinuddin Quadri Over a year ago

@heemayl : correct, thanks! it is more efficient. Added it to the answer too

lax123 Over a year ago

Awesome!!.. Thanks for help

tkhurana96 · Accepted Answer · 2017-12-31 19:49:56Z

0

In your case, I think str1.split()[1] might help

answered Dec 31, 2017 at 19:49

tkhurana96

9397 silver badges27 bronze badges

Collectives™ on Stack Overflow

Get a particular string after matching a string in regex python

2 Answers 2

4 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

4 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related