Extract Number before a Character in a String Using Python

Question

I\'m trying to extract the number before character \"M\" in a series of strings. The strings may look like:

\"107S33M15H\"
\"33M100S\"
\"12M100H33M\"
         


        

Answer 1

You can use rpartition to achieve that job.

s = '107S33M15H'    
prefix = s.rpartition('M')[0]

Answer 2

You may use a simple (\d+)M regex (1+ digit(s) followed with M where the digits are captured into a capture group) with re.findall.

See IDEONE demo:

import re
s = "107S33M15H\n33M100S\n12M100H33M"
print(re.findall(r"(\d+)M", s))

And here is a regex demo