Python Exercises: Sum of all prime numbers in a list of integers

Last update on April 24 2025 12:43:59 (UTC/GMT +8 hours)

94. Sum of Prime Numbers in List

From Wikipedia,
A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime because the only ways of writing it as a product, 1 × 5 or 5 × 1, involve 5 itself. However, 4 is composite because it is a product (2 × 2) in which both numbers are smaller than 4.

Write a Python program to calculate the sum of all prime numbers in a given list of positive integers.

Sample Data:
([1, 3, 4, 7, 9]) -> 10
([]) -> Empty list!
([11, 37, 444]) -> 48

Sample Solution-1:

Python Code:

def test(nums):
    if len(nums) > 0:
        return sum(list(filter(lambda x: (x > 1 and all(x % y != 0 for y in range(2, x))), nums))) 
    return "Empty list!"

nums = [1, 3, 4, 7, 9]
print("Original list:")
print(nums)
print("Sum of all prime numbers in the said list of numbers:")
print(test(nums))
nums = []
print("\nOriginal list:")
print(nums)
print("Sum of all prime numbers in the said list of numbers:")
print(test(nums))
nums = [11, 37, 444]
print("\nOriginal list:")
print(nums)
print("Sum of all prime numbers in the said list of numbers:")
print(test(nums))

Sample Output:

Original list:
[1, 3, 4, 7, 9]
Sum of all prime numbers in the said list of numbers:
10

Original list:
[]
Sum of all prime numbers in the said list of numbers:
Empty list!

Original list:
[11, 37, 444]
Sum of all prime numbers in the said list of numbers:
48

Flowchart:

Sample Solution-2:

Python Code:

def test(nums):
    if len(nums) > 0:    
        e = lambda a: 2 in [a, 2**a%a]
        return sum(filter(e, nums))
    else:
        return "Empty list!"

nums = [1, 3, 4, 7, 9]
print("Original list:")
print(nums)
print("Sum of all prime numbers in the said list of numbers:")
print(test(nums))
nums = []
print("\nOriginal list:")
print(nums)
print("Sum of all prime numbers in the said list of numbers:")
print(test(nums))
nums = [11, 37, 444]
print("\nOriginal list:")
print(nums)
print("Sum of all prime numbers in the said list of numbers:")
print(test(nums))

Sample Output:

Original list:
[1, 3, 4, 7, 9]
Sum of all prime numbers in the said list of numbers:
10

Original list:
[]
Sum of all prime numbers in the said list of numbers:
Empty list!

Original list:
[11, 37, 444]
Sum of all prime numbers in the said list of numbers:
48

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python program to filter a list of integers to identify prime numbers and then calculate their sum, printing the final total.
• Write a Python function that takes a list of positive integers, determines which numbers are prime, and returns the sum of these primes.
• Write a Python script to prompt the user for a list of numbers, compute the sum of the primes among them, and display the result, handling empty lists appropriately.
• Write a Python program to generate a random list of integers, extract the prime numbers using a helper function, and then output the sum of the primes.

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