python: conditional statement with else statement in loop

Question

How would I be able to make this if statement more efficient?

 if ',' in my_string:
 my_string = my_string.split(',', 1)[0]
 return ', '
 elif '.' in my_string:
 my_string = my_string.split('.', 1)[0]
 return '. '
 elif '?' in my_string:
 my_string = my_string.split('?', 1)[0]
 return '? '
 elif '!' in my_string:
 my_string = my_string.split('!', 1)[0]
 return '! '
 elif ';' in my_string:
 my_string = my_string.split(';', 1)[0]
 return '; '
 else: 
 self.qstring = my_string
 return None

I could make a list like:

my_list = [',', '.', '?', '!', ';'] 

and loop through, but I'm not sure how to still use the else statement if I put it all in a loop. Any thoughts?

• Martijn Pieters: Presumably my_string is preserved somewhere? As your code stands, there is no point in assigning to my_string, or even splitting the text, as you return immediately after the split and are thus discarding my_string.

Answer 1

Loop over the list you have:

for delim in my_list:
 if delim in my_string:
 my_string = my_string.split(delim, 1)[0]
 return delim + ' '
self.qstring = my_string
return None

Because the loop will return the part after the loop is not executed if any delimiter matched.

Answer 2

Use re:

import re
(mystring, delim) = re.split(r'([,\.\?;] )', mystring, 1)[:2]
return delim

• jpm: I like the re approach, but it looks like OP wants to preserve the match and return it.
• jpm: Do . and ? need to be escaped inside a character class?

Answer 3

Remove all the assignments to my_string. Since this is a local variable, this achieves nothing because the value is never returned.