CODEWITHSUNDEEP
pythonregex
Or Perez
Or Perez

Reputation: 1

regex issue with numbers (python)

I have a string thath goes like that: 

<123, 321>

the range of the numbers can be between 0 to 999.

I need to insert those coordinates as fast as possible into two variables, so i thought about regex. I've already splitted the string to two parts and now i need to isolate the integer from all the other characters. I've tried this pattern:

 ^-?[0-9]+$

but the output is: 

[]

any help? :)

Upvotes: 0

Views: 104

Answers (3)

nu11p01n73R
nu11p01n73R

Reputation: 26667

All you need to do is to get rid of the anchors( ^ and $)

>>> import re
>>> string = "<123, 321>"
>>> re.findall(r"-?[0-9]+", string)
['123', '321']
>>>

Note ^ $ Anchors at the start and end of patterns -?[0-9]+ ensures that the string consists only of digits.

That is the regex engine attempts to match the pattern from the start of the string, ^ using -?[0-9]+ till the end of the string $. But it fails because < cannot be matched by -?[0-9]+

Where as the re.findall will find all substrings that match the pattern -?[0-9]+, that is the digits.

Upvotes: 1

Konstantin
Konstantin

Reputation: 25329

If your strings follow the same format <123, 321> then this should be a little bit faster than regex approach

def str_translate(s):
    return s.translate(None, " <>").split(',')

In [52]: str_translate("<123, 321>")
Out[52]: ['123', '321']

Upvotes: 2

Raniz
Raniz

Reputation: 11113

"^-?[0-9]+$" will only match a string that contains a number and nothing else.

You want to match a group and the extract that group:

>>> pattern = re.compile("(-?[0-9]+)")
>>> pattern.findall("<123, 321>")
['123', '321']

Upvotes: 0

Related Questions