In the above Python program to calculate the number of digits and letters in a string we used built-in function isdigit() to calculate the number of digits and isalpha() to calculate the number of letters.

str = input("Input a string")
d=l=0 
for s in str:
    if s.isdigit(): 
        d=d+1
    elif s.isalpha(): 
        l=l+1
    else:
        pass
print("Letters", l)
print("Digits", d)

Sample Output:
Input a string : Hello5World
Letters 10
Digits 1