How to check a string for specific characters?


How can I check if a string value has exact characters in it using Python2? Specifically, I am looking to detect if it has dollar signs ("$"), commas (","), and numbers.

5/2/2013 1:39:52 AM

Accepted Answer

Assuming your string is s:

'$' in s        # found
'$' not in s    # not found

# original answer given, but less Pythonic than the above...
s.find('$')==-1 # not found
s.find('$')!=-1 # found

And so on for other characters.

... or

pattern = re.compile(r'\d\$,')
if pattern.findall(s):
    print('Not found')

... or

chars = set('0123456789$,')
if any((c in chars) for c in s):
    print('Not Found')

[Edit: added the '$' in s answers]

5/26/2014 1:03:02 AM

user Jochen Ritzel said this in a comment to an answer to this question from user dappawit. It should work:

('1' in var) and ('2' in var) and ('3' in var) ...

'1', '2', etc. should be replaced with the characters you are looking for.

See this page in the Python 2.7 documentation for some information on strings, including about using the in operator for substring tests.

Update: This does the same job as my above suggestion with less repetition:

# When looking for single characters, this checks for any of the characters...
# ...since strings are collections of characters
any(i in '<string>' for i in '123')
# any(i in 'a' for i in '123') -> False
# any(i in 'b3' for i in '123') -> True

# And when looking for subsrings
any(i in '<string>' for i in ('11','22','33'))
# any(i in 'hello' for i in ('18','36','613')) -> False
# any(i in '613 mitzvahs' for i in ('18','36','613')) ->True

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