[python] Replace first occurrence of string in Python

I have some sample string. How can I replace first occurrence of this string in a longer string with empty string?

regex = re.compile('text')
match = regex.match(url)
if match:
    url = url.replace(regex, '')

Use re.sub directly, this allows you to specify a count:

regex.sub('', url, 1)

(Note that the order of arguments is replacement, original not the opposite, as might be suspected.)