Sum 2D array in Python using map() function

In this tutorial, we are going to find the sum of a 2D array using map() function in Python.

The map() function takes two arguments: function and iterable. It applies the function to every element of the iterable and returns a map object. We can convert the map object into a list or other iterable.

Let's see how to find the sum of a 2D array using the map function ?

Steps to Sum a 2D Array

• Initialize the 2D array using nested lists.
• Pass the sum function and 2D array to the map() function.
• Convert the map object to a list to get row sums.
• Find the total sum using sum() on the result.

Example - Complete Implementation

Here's how to sum all elements in a 2D array using map() ?

# initializing the 2D array
array = [
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9]
]

# Step 1: Get sum of each row using map()
row_sums = list(map(sum, array))
print("Sum of each row:", row_sums)

# Step 2: Get total sum of all elements
total_sum = sum(row_sums)
print("Total sum of 2D array:", total_sum)

Sum of each row: [6, 15, 24]
Total sum of 2D array: 45

How It Works

The map(sum, array) applies the sum() function to each row (sub-list) in the 2D array:

• Row 1: [1, 2, 3] ? sum = 6
• Row 2: [4, 5, 6] ? sum = 15
• Row 3: [7, 8, 9] ? sum = 24

Then sum([6, 15, 24]) gives us the final result: 45.

One-Line Solution

You can combine both steps into a single line ?

array = [
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9]
]

# Direct sum using map()
total = sum(map(sum, array))
print("Total sum:", total)

Total sum: 45

Conclusion

Using map(sum, array) is an efficient way to sum a 2D array in Python. It first calculates the sum of each row, then sums those results to get the total.