Suppose I have this string:
s = "blah blah blah"
Using Python regex, how can I replace each instance of "blah" with a different value (e.g. I have a list of values v = ("1", "2", "3")
Add a comment
|
4 Answers
You could use a re.sub callback:
import re
def callback(match):
return next(callback.v)
callback.v=iter(('1','2','3'))
s = "blah blah blah"
print(re.sub(r'blah',callback,s))
yields
1 2 3
3 Comments
Zach Kelling
Adding the iterable to the function as an attribute is a really nice approach.
Jochen Ritzel
a closure would be way saner.
You could use re.sub, which takes a string or function and applies it to each match:
>>> re.sub('blah', lambda m, i=iter('123'): next(i), 'blah blah blah')
<<< '1 2 3'
Comments
I think you don't really need a regex.
for x in v:
s = s.replace('blah', x, 1)
However if you really wanted a regex:
import re
for x in v:
s = re.sub('blah', x, s, count=1)
1 Comment
Aran-Fey
I see two problems with this: 1) It's inefficient, because each call to
.replace starts searching for an occurence to replace at the start of the string. 2) It straight up doesn't work if v contains the word "blah".