w3resource

Python: Find the indices of two numbers that sum to 0 in a given list

Python Programming Puzzles: Exercise-29 with Solution

Write a Python program to find the indices of two numbers that sum to 0 in a given list of numbers.

Input:
[1, -4, 6, 7, 4]
Output:
[4, 1]

Input:
[1232, -20352, 12547, 12440, 741, 341, 525, 20352, 91, 20]
Output:
[1, 7]

Visual Presentation:

Python: Find the indices of two numbers that sum to 0 in a given list.

Sample Solution-1:

Python Code:

# License: https://bit.ly/3oLErEI

# Define a function named 'test' that takes a list of numbers 'nums' as input
def test(nums):
    # Create a set 's' from the given list 'nums'
    s = set(nums)
    
    # Iterate over each element 'i' in the set 's'
    for i in s:
        # Check if the negation of 'i' is also in the set 's'
        if -i in s:
            # If found, return the indices of 'i' and its negation in the original list 'nums'
            return [nums.index(i), nums.index(-i)]

# Assign a specific list of numbers 'nums' to the variable
nums = [1, -4, 6, 7, 4]

# Print the original list of numbers 'nums'
print("Original List:")
print(nums)

# Print a message indicating the operation to be performed
print("Indices of two numbers that sum to 0 in the said list:")

# Print the result of the test function applied to the 'nums' list
print(test(nums))

# Assign another specific list of numbers 'nums' to the variable
nums = [1232, -20352, 12547, 12440, 741, 341, 525, 20352, 91, 20]

# Print the original list of numbers 'nums'
print("\nOriginal List:")
print(nums)

# Print a message indicating the operation to be performed
print("Indices of two numbers that sum to 0 in the said list:")

# Print the result of the test function applied to the 'nums' list
print(test(nums))

Sample Output:

Original List:
[1, -4, 6, 7, 4]
Indices of two numbers that sum to 0 in the said list:
[4, 1]

Original List:
[1232, -20352, 12547, 12440, 741, 341, 525, 20352, 91, 20]
Indices of two numbers that sum to 0 in the said list:
[1, 7]

Flowchart:

Flowchart: Python - Find the indices of two numbers that sum to 0 in a given list.

Sample Solution-2:

Python Code:

# License: https://bit.ly/3oLErEI

# Define a function named 'test' that takes a list of numbers 'nums' as input
def test(nums):
    # Initialize an empty list 'result' to store the indices
    result = []

    # Iterate over each index 'ind' in the range of the length of the list 'nums'
    for ind in range(len(nums)):
        # Iterate over each index 'i' in the range of the length of the list 'nums'
        for i in range(len(nums)):
            # Check if the current index 'ind' is not equal to the other index 'i'
            # and if the sum of the numbers at the current index and the other index is zero
            if ind != i and nums[ind] + nums[i] == 0:
                # Append the current index 'ind' and the other index 'i' to the 'result' list
                result.append(ind)
                result.append(i)
                # Found the indices; no need to go through the whole list
                return result

# Assign a specific list of numbers 'nums' to the variable
nums = [1, -4, 6, 7, 4]

# Print the original list of numbers 'nums'
print("Original List:")
print(nums)

# Print a message indicating the operation to be performed
print("Indices of two numbers that sum to 0 in the said list:")

# Print the result of the test function applied to the 'nums' list
print(test(nums))

# Assign another specific list of numbers 'nums' to the variable
nums = [1232, -20352, 12547, 12440, 741, 341, 525, 20352, 91, 20]

# Print the original list of numbers 'nums'
print("\nOriginal List:")
print(nums)

# Print a message indicating the operation to be performed
print("Indices of two numbers that sum to 0 in the said list:")

# Print the result of the test function applied to the 'nums' list
print(test(nums))

Sample Output:

Original List:
[1, -4, 6, 7, 4]
Indices of two numbers that sum to 0 in the said list:
[1, 4]

Original List:
[1232, -20352, 12547, 12440, 741, 341, 525, 20352, 91, 20]
Indices of two numbers that sum to 0 in the said list:
[1, 7]

Flowchart:

Flowchart: Python - Find the indices of two numbers that sum to 0 in a given list.

Python Code Editor :

Have another way to solve this solution? Contribute your code (and comments) through Disqus.

Previous: Select a string from a given list of strings with the most unique characters.
Next: Find the list that has fewer total characters (including repetitions).

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.



Become a Patron!

Follow us on Facebook and Twitter for latest update.

It will be nice if you may share this link in any developer community or anywhere else, from where other developers may find this content. Thanks.

https://198.211.115.131/python-exercises/puzzles/python-programming-puzzles-29.php