Python program to calculate the number of digits and letters in a string

Last Updated : 09 Jan, 2025

In this article, we will check various methods to calculate the number of digits and letters in a string. Using a for loop to remove empty strings from a list involves iterating through the list, checking if each string is not empty, and adding it to a new list.

s = "Hello123!"

# Initialize counters for letters and digits
l_c = 0
d_c = 0

# Iterate through each character in the string
for char in s:
  
  # Check if the character is a letter
    if char.isalpha():  
        l_c += 1
        
   # Check if the character is a digit
    elif char.isdigit(): 
        d_c += 1

print(f"Letters: {l_c}")
print(f"Digits: {d_c}")

Output

Letters: 5
Digits: 3

Explanation

for loop iterates through each character in the string s, using char.isalpha() to check if a character is a letter and char.isdigit() to check if it is a digit.
counters l_c and d_c are incremented based on the character type, and the final counts of letters and digits are printed.

Using `filter()`

Using filter() to remove empty strings from a list allows you to apply a filtering condition, such as checking whether each string is non-empty, and return a list of only the strings that meet the condition.

s = "Hello123!"

# Count letters using filter and len
l_c = len(list(filter(str.isalpha, s)))

# Count digits using filter and len
d_c = len(list(filter(str.isdigit, s)))

print(f"Letters: {l_c}")
print(f"Digits: {d_c}")

Output

Letters: 5
Digits: 3

Explanation

filter(str.isalpha, s) filters out only the alphabetic characters from the string s, and len(list(...)) counts the number of alphabetic characters.
filter(str.isdigit, s) filters out the digits, and len(list(...)) counts the number of digits in the string, with both counts being printed.

Using `collections.Counter`

Using collections.Counter to count the number of letters and digits in a string allows to check the occurrences of each character. The Counter class creates a dictionary-like object where characters are keys, and their counts are values.

from collections import Counter

# Input string
s = "Hello123!"

# Count frequencies of each character
f = Counter(s)

# Count letters and digits
l_c = sum(1 for char in f if char.isalpha())
d_c = sum(1 for char in f if char.isdigit())

# Print the counts
print(f"Letters: {l_c}")
print(f"Digits: {d_c}")

Output

Letters: 4
Digits: 3

Explanation

The Counter(s) counts the frequency of each character in the string s, storing the results in a Counter object f.
The sum(1 for char in f if char.isalpha()) counts the number of alphabetic characters, and sum(1 for char in f if char.isdigit()) counts the number of digits in the string, with the counts being printed.