Python – 3D Matrix to Coordinate List

Given a Matrix, row’s each element is list, pair each column to form coordinates.

Input : test_list = [[[9, 2], [10, 3]], [[13, 6], [19, 7]]] Output : [(9, 10), (2, 3), (13, 19), (6, 7)] Explanation : Column Mapped Pairs. Input : test_list = [[[13, 6], [19, 7]]] Output : [(13, 19), (6, 7)] Explanation : Column Mapped Pairs.

Method #1 : Using loop + zip()

In this, we iterate for all the paired elements in inner tuples list, which is paired using zip(), and append the result list.

Python3

# Python3 code to demonstrate working of
# 3D Matrix to Coordinate List
# Using loop + zip()

# initializing list
test_list = [[[5, 6, 7], [2, 4, 6]], [[9, 2], [10, 3]], [[13, 6], [19, 7]]]

# printing original list
print("The original list is : " + str(test_list))

res = []
for sub1, sub2 in test_list:

    # zip() used to form pairing
    for ele in zip(sub1, sub2):
        res.append(ele)

# printing result
print("Constructed Pairs : " + str(res))

Output

The original list is : [[[5, 6, 7], [2, 4, 6]], [[9, 2], [10, 3]], [[13, 6], [19, 7]]]
Constructed Pairs : [(5, 2), (6, 4), (7, 6), (9, 10), (2, 3), (13, 19), (6, 7)]

Time Complexity: O(n^2), where n is the total number of elements in the 3D matrix.

Auxiliary Space: O(n)

Method #2 : Using list comprehension

In this, we perform task of of above method in shorthand using list comprehension.

Python3

# Python3 code to demonstrate working of
# 3D Matrix to Coordinate List
# Using loop + zip()

# initializing list
test_list = [[[5, 6, 7], [2, 4, 6]], [[9, 2], [10, 3]], [[13, 6], [19, 7]]]

# printing original list
print("The original list is : " + str(test_list))

# list comprehension to perform task in shorthand
res = [ele for sub1, sub2 in test_list for ele in zip(sub1, sub2)]

# printing result
print("Constructed Pairs : " + str(res))

Output

The original list is : [[[5, 6, 7], [2, 4, 6]], [[9, 2], [10, 3]], [[13, 6], [19, 7]]]
Constructed Pairs : [(5, 2), (6, 4), (7, 6), (9, 10), (2, 3), (13, 19), (6, 7)]