Python Exercise: Calculate the number of upper / lower case letters in a string

Last update on April 22 2025 12:58:53 (UTC/GMT +8 hours)

7. Count Uppercase and Lowercase Letters in a String

Write a Python function that accepts a string and counts the number of upper and lower case letters.

Sample Solution:

Python Code:

# Define a function named 'string_test' that counts the number of upper and lower case characters in a string 's'
def string_test(s):
    # Create a dictionary 'd' to store the count of upper and lower case characters
    d = {"UPPER_CASE": 0, "LOWER_CASE": 0}
    
    # Iterate through each character 'c' in the string 's'
    for c in s:
        # Check if the character 'c' is in upper case
        if c.isupper():
            # If 'c' is upper case, increment the count of upper case characters in the dictionary
            d["UPPER_CASE"] += 1
        # Check if the character 'c' is in lower case
        elif c.islower():
            # If 'c' is lower case, increment the count of lower case characters in the dictionary
            d["LOWER_CASE"] += 1
        else:
            # If 'c' is neither upper nor lower case (e.g., punctuation, spaces), do nothing
            pass
    
    # Print the original string 's'
    print("Original String: ", s)
    
    # Print the count of upper case characters
    print("No. of Upper case characters: ", d["UPPER_CASE"])
    
    # Print the count of lower case characters
    print("No. of Lower case Characters: ", d["LOWER_CASE"])

# Call the 'string_test' function with the input string 'The quick Brown Fox'
string_test('The quick Brown Fox') 

Sample Output:

Original String :  The quick Brow Fox                                                                         
No. of Upper case characters :  3                                                                             
No. of Lower case Characters :  13 

Explanation:

In the exercise above the code defines a function named "string_test()" that counts the number of upper case and lower case characters in the given string 's'. It utilizes a dictionary to store the counts and then prints the original string along with the counts of upper and lower case characters. Finally, it demonstrates the function by calling it with the input string 'The quick Brown Fox'.

Pictorial presentation:

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python function that iterates over a string and uses conditional statements to count uppercase and lowercase letters separately.
• Write a Python function that uses list comprehensions to create two lists: one for uppercase and one for lowercase letters, then returns their lengths.
• Write a Python function that employs regular expressions to find all uppercase and lowercase letters in a string and count them.
• Write a Python function that uses the collections.Counter to tally uppercase and lowercase letters and then extracts the counts.

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