﻿ Python: Add two given lists of different lengths, start from left, use itertools module - w3resource

# Python: Add two given lists of different lengths, start from left, use itertools module

## Python Itertools: Exercise-37 with Solution

Write a Python program to add two given lists of different lengths, starting from the left, using the itertools module.

Sample Solution:

Python Code:

``````from itertools import zip_longest

def elementswise_left_join(l1, l2):
result = [a + b for a,b in zip_longest(l1, l2, fillvalue=0)][::1]
return result

nums1 = [2, 4, 7, 0, 5, 8]
nums2 = [3, 3, -1, 7]
print("\nOriginal lists:")
print(nums1)
print(nums2)
print("\nAdd said two lists from left:")
print(elementswise_left_join(nums1, nums2))

nums3 = [1, 2, 3, 4, 5, 6]
nums4 = [2, 4, -3]
print("\nOriginal lists:")
print(nums3)
print(nums4)
print("\nAdd said two lists from left:")
print(elementswise_left_join(nums3, nums4))
```
```

Sample Output:

```Original lists:
[2, 4, 7, 0, 5, 8]
[3, 3, -1, 7]

Add said two lists from left:
[5, 7, 6, 7, 5, 8]

Original lists:
[1, 2, 3, 4, 5, 6]
[2, 4, -3]

Add said two lists from left:
[3, 6, 0, 4, 5, 6]
```

Python Code Editor:

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Next: Write a Python program to interleave multiple given lists of different lengths using itertools module.

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