String contains any character in group?

Question

I have a set of characters: \,/,?,% etc. I also have a string, lets say "This is my string % my string ?"

I want to check if any of the characters are present in the string.

This is not to check for a substring, but to check for a character in a set.

I could do this:

my_str.find( "/" ) or my_str.find( "\\" ) or my_str.find( "?" )

but it's very ugly and inefficient.

Is there a better way?

Answer 1

You could use any here.

>>> string = r"/\?%"
>>> test = "This is my string % my string ?"
>>> any(elem in test for elem in string)
True
>>> test2 = "Just a test string"
>>> any(elem in test2 for elem in string)
False

Answer 2

I think Sukrit probably gave the most pythonic answer. But you can also solve this with set operations:

>>> test_characters = frozenset(r"/\?%")
>>> test = "This is my string % my string ?"
>>> bool(set(test) & test_characters)
True
>>> test2 = "Just a test string"
>>> bool(set(test2) & test_characters)
False

Answer 3

Use regex!

import re

def check_existence(text):
    return bool(re.search(r'[\\/?%]', text))

text1 = "This is my string % my string ?"
text2 = "This is my string my string"

print check_existence(text1)
print check_existence(text2)

Answer 4

In [1]: import re
In [2]: RE = re.compile('[\\\/\?%]')
In [3]: RE.search('abc')

In [4]: RE.search('abc?')
Out[4]: <_sre.SRE_Match at 0x1081bc1d0>
In [5]: RE.search('\\/asd')
Out[5]: <_sre.SRE_Match at 0x1081bc3d8>

None indicates non characters in the set are present in the target string.

Answer 5

And of course the most non-Pythonic way, but at least to me more readable.

Define the function:

def containsSpecialCharacters(self, string: str, test: str) -> bool:
    for special in string:
        if special in test:
            return True
    return False

This call:

string = r"/\?%"
test = "This is my string % my string ?"
print(self.containsSpecialCharacters(string, test))

returns True

This call

test2 = "Just a test string" 
print(self.containsSpecialCharacters(string, test2))

returns False