Check if String Contains Only Certain Characters in Python

In Python, we can easily check if a string contains certain characters using a for loop and check individually if each character is one of those characters or not.

def containsCertainChars(string, chars):
    for char in string:
        if char in chars:
           return True
    return False

print(containsCertainChars("Hello World!", "H"))
print(containsCertainChars("Hello World!", "olz"))
print(containsCertainChars("Hello World!", "z"))

#Output:
True
True
False

When working with strings, it can be useful to know if there are certain characters contained in a string variable.

In Python, we can easily get if a string contains certain characters in a string looping over each character of the string and seeing if it is one of the given characters or not.

Below is a function which will check if a string has certain characters or not for you in a string using Python.

def containsCertainChars(string, chars):
    for char in string:
        if char in chars:
           return True
    return False

print(containsCertainChars("Hello World!", "H"))
print(containsCertainChars("Hello World!", "olz"))
print(containsCertainChars("Hello World!", "z"))

#Output:
True
True
False

Checking if a Certain Character Appears in a String Using Python

The example above is useful if you want to check if any character in your string or list is in a string. We can also use Python to check if each of the characters appear in a string.

To do this, we will loop over the character and create a dictionary which stores if we find each of the character.

Below is a Python function which will check if a string has a particular character.

def checkEachChar(string, chars):
    checks = {}
    for char in chars:
        checks[char] = string.count(char) > 0
    return checks

print(checkEachChar("Hello World!", "Hl"))
print(checkEachChar("This is a string with some words.", "SwDds"))
print(checkEachChar("What's up?", "Uu"))
print(checkEachChar("Brrrr", "Pr"))

#Output:
{'H': True, 'l': True}
{'S': False, 'w': True, 'D': False, 'd': True, 's': True}
{'U': False, 'u': True}
{'P': False, 'r': True}

Checking if a Vowel Appears in a String Using Python

When working with strings, it can be useful to know if there are any vowels contained in a string variable.

In Python, we can easily check if a string contains vowels in a string looping over each character of the string and seeing if it is a vowel or not.

We can take the functions from above and modify them slightly to see if there are any vowels in a string.

Below is a Python function which will check if a string has a specific vowel.

def checkEachVowel(string):
    checks = {}
    string = string.lower()
    for vowel in "aeiou":
        checks[vowel] = string.count(vowel) > 0
    return checks

print(checkEachVowel("Hello World!"))
print(checkEachVowel("This is a string with some words."))
print(checkEachVowel("What's up?"))
print(checkEachVowel("Brrrr"))

#Output:
{'a': False, 'e': True, 'i': False, 'o': True, 'u': False}
{'a': True, 'e': True, 'i': True, 'o': True, 'u': False}
{'a': True, 'e': False, 'i': False, 'o': False, 'u': True}
{'a': False, 'e': False, 'i': False, 'o': False, 'u': False}

Hopefully this article has been useful for you to check if a string contains certain characters using Python.