Check if a string contains any Uppercase letters in Python

# Table of Contents

1. Check if a string contains any Uppercase letters in Python
2. Check if a string contains any Uppercase letters using a for loop
3. Check if a string contains any Uppercase letters using re.search()

# Check if a string contains any Uppercase letters in Python

To check if a string contains any uppercase letters:

1. Use a generator expression to iterate over the string.
2. Use the str.isupper() method to check if each character is uppercase.
3. If the condition is met for any of the characters, the string contains uppercase letters.

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my_str = 'Bobby'

contains_uppercase = any(char.isupper() for char in my_str)
print(contains_uppercase)  # 👉️ True

if contains_uppercase:
    # 👇️ this runs
    print('The string contains uppercase letters')
else:
    print('The string does NOT contain any uppercase letters')

# --------------------------------------------------

# ✅ Extract the uppercase letters from a string
my_str = 'BOBBYhadz123'

only_upper = ''.join(char for char in my_str if char.isupper())
print(only_upper)  # 👉️ BOBBY

only_upper = [char for char in my_str if char.isupper()]
print(only_upper)  # 👉️ ['B', 'O', 'B', 'B', 'Y']

We used a generator expression to iterate over the string.

On each iteration, we use the str.isupper() method to check if the current character is an uppercase letter.

The str.isupper() method returns True if all cased characters in the string are uppercase and the string contains at least one cased character, otherwise False is returned.

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my_str = 'BOBBYHADZ.COM'


all_uppercase = my_str.isupper()
print(all_uppercase)  # 👉️ True

The any function takes an iterable as an argument and returns True if any element in the iterable is truthy.

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my_str = 'Bobby'

contains_uppercase = any(char.isupper() for char in my_str)
print(contains_uppercase)  # 👉️ True

if contains_uppercase:
    # 👇️ this runs
    print('The string contains uppercase letters')
else:
    print('The string does NOT contain any uppercase letters')

Alternatively, you can use a for loop.

# Check if a string contains any Uppercase letters using a for loop

This is a three-step process:

1. Use a for loop to iterate over the string.
2. Use the str.isupper() method to check if each character is an uppercase letter.
3. If the condition is met, set a variable to True and break out of the loop.

Copied!
contains_uppercase = False

my_str = 'Bobby'

for char in my_str:
    if char.isupper():
        contains_uppercase = True
        break

print(contains_uppercase)  # 👉️ True

We used a for loop to iterate over the string.

On each iteration, we check if the current character is an uppercase letter.

The break statement breaks out of the innermost enclosing for or while loop.

# Check if a string contains any Uppercase letters using re.search()

Alternatively, you can use the re.search() method.

The re.search() method will return a match object if the string contains uppercase letters, otherwise, None is returned.

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import re


def contains_uppercase(string):
    return bool(re.search(r'[A-Z]', string))


if contains_uppercase('Bobby'):
    # 👇️ this runs
    print('The string contains uppercase letters')
else:
    print('The string does NOT contain any uppercase letters')


print(contains_uppercase('A b c'))  # 👉️ True
print(contains_uppercase('abc 123'))  # 👉️ False
print(contains_uppercase(''))  # 👉️ False
print(contains_uppercase(' '))  # 👉️ False

The re.search() method looks for the first location in the string where the provided regular expression produces a match.

The first argument we passed to the re.search() method is a regular expression.

The square brackets [] are used to indicate a set of characters.

We used the bool() class to convert the match object to True or the None value to False.

# Additional Resources

You can learn more about the related topics by checking out the following tutorials:

• Check if a String contains a Number in Python
• Check if a String contains an Element from a List in Python
• How to Check if a String contains Vowels in Python
• Check if a string does NOT contain substring in Python