Sum of digits in python using lambda

Question

How can I convert these two functions to use lambda notation?

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Python Lambda: Exercise-23 with Solution
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Python: Tips of the Day
How do you sum a list of a digit in python?
How do you add two numbers using lambda expression?
What is Lamda function in python?

def sum_digits(number):
    if number == 0:
        return 0
    else:
        return (number % 10) + sum_digits(number / 10)

def count_digit(number):
    if number == 0:
        return 0
    else:
        return 1 + count_digit(number/10)

asked Apr 9, 2017 at 2:30

1

sum_digits = lambda number: 0 if number == 0 else (number % 10) + sum_digits (number / 10)

count_digit = lambda number: 0 if number == 0 else 1 + count_digit(number/10)

Incidentally, this is a bad time to use lambdas, since you need the function names in order for them to call themselves. The point of lambdas is that they're anonymous.

answered Apr 9, 2017 at 2:35

Arya McCarthyArya McCarthy

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5

Use a conditional expression for the body of the lambda:

>>> sum_digits = lambda n: 0 if n == 0 else (n % 10) + sum_digits(n // 10)
>>> count_digit = lambda n: 0 if n == 0 else 1 + count_digit(n // 10)

Also, if is preferred to use // for the division so that the code will still work in Python 3.

answered Apr 9, 2017 at 2:35

Raymond HettingerRaymond Hettinger

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0

A string-oriented approach wouldn't require recursion:

sum_of_digits = lambda n: sum(int(d) for d in str(n))
count_digit = lambda n: len(str(n))

answered Nov 12, 2018 at 7:41

martineaumartineau

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sum_digits = lambda number: 0 if number == 0 else (number % 10) + sum_digits (number//10)
count_digit = lambda number: 0 if number == 0 else 1 + count_digit(number//10)
print(sum_digits(2546))
print(count_digit(2546))

Will work on python 3 too...

answered Apr 9, 2017 at 12:39

print(list(map(lambda x: sum(int(i) for i in str(x)),list(map(int,input().split())))))

this might be useful for reading and using lamda function on the same line.

Yunnosch

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answered Apr 15, 2021 at 5:35

Last update on August 19 2022 21:50:46 (UTC/GMT +8 hours)

Python Lambda: Exercise-23 with Solution

Write a Python program to calculate the sum of the positive and negative numbers of a given list of numbers using lambda function.

Sample Solution:

Python Code :

nums = [2, 4, -6, -9, 11, -12, 14, -5, 17]
print("Original list:",nums)

total_negative_nums = list(filter(lambda nums:nums<0,nums))
total_positive_nums = list(filter(lambda nums:nums>0,nums))

print("Sum of the positive numbers: ",sum(total_negative_nums))
print("Sum of the negative numbers: ",sum(total_positive_nums))

Sample Output:

Original list: [2, 4, -6, -9, 11, -12, 14, -5, 17]
Sum of the positive numbers:  -32
Sum of the negative numbers:  48

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