CODEWITHSUNDEEP
python-3.xregex
Yash Saraiya
Yash Saraiya

Reputation: 1055

Regular expression to check whether one or more special characters are present in string

I am using the below code:

email = "yash@"
string_check= re.compile('[@.]')

if(string_check.search(email) == None):
    print('invalid')
else:
    print('valid')

This rightly evaluates to 'valid'. However, if I want to ensure that the string strictly contains both '@' and '.' then what is the way in which I can achieve it?

I have also tried below code but it does not work with special charcaters:

import re
arr = ['@', '.']
# str = "hello people"

str = "yash"
if any(re.findall('|'.join(arr), str)):
    print('Found a match')
else:
    print('No match found')

This evaluates to "Found a match" despite having neither "@" nor "."

Upvotes: 1

Views: 30

Answers (2)

Riccardo Bucco
Riccardo Bucco

Reputation: 15364

The solution provided by @Andrej Kesely does work, but the complexity could be much much better. His solution has a complexity of O(mn), where m is the length of arr and n is the length of email. Here is an alternative solution (might look worse, but it has a better complexity):

from collections import Counter

counter = Counter(email)
if all(counter[ch] > 0 for ch in arr):
    print('valid')
else:
    print('non valid')

Here the complexity is O(max(m, n))

Upvotes: 0

Andrej Kesely
Andrej Kesely

Reputation: 195468

You can use all() function, no need to use regex:

arr = ['@', '.']
email = "yash@"

if all(ch in email for ch in arr):
    print('valid')
else:
    print('not valid')

Prints:

not valid

Upvotes: 2

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