CODEWITHSUNDEEP
pythonregex
enedene
enedene

Reputation: 3635

Regex match based on prefix and suffix

I'm using python 3 and re module.

Here are the strings:

s1 = "http://52portal/flood-2011-year-39090/gallery?p=3"
s2 = "http://52portal/flood-2011-year-39090"

I need to get 39090 number, ids are always given so that number has a prefix - and no particular suffix.

I have an implementation when no other numbers are in url:

pattern = r'-([0-9]+)'
re.findall(pattern, s)[0]

How would I tell the program to ignore the number that has suffix and prefix -?

Upvotes: 0

Views: 3481

Answers (2)

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 626689

You need to find the right-side boundary. It can be / or end of string. 

(?<=-)\d+(?=/|$)

Here, (?<=-) is a positive look-behind that checks if there is a hyphen before 1 or more digits (\d+) and (?=/|$) is a positive look-ahead that makes sure there is / or end of string right after that sequence.

See demo

Here is sample code:

import re
p = re.compile(r'(?<=-)\d+(?=/|$)')
test_str = "http://52portal/flood-2011-year-39090/gallery?p=3\nhttp://52portal/flood-2011-year-39090"
print(re.findall(p, test_str))

Upvotes: 3

Narendrasingh Sisodia
Narendrasingh Sisodia

Reputation: 21437

Try as

(?<=-)[0-9]+?(?=/|$)

https://regex101.com/r/sY3qI2/2

Upvotes: 1

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