Python program to create 3D list.

In Python, A 3D list is also called a three-dimensional array (list of lists of lists). It can be visualized as a cube or a set of tables stacked together. It is commonly used to represent data with three indices. For example, a matrix of images (height, width, depth).

In this article, we are going to learn how to create a 3D list. As Python does not have built-in support for multi-dimensional arrays like other programming languages, but using the nested lists and loops, we can create and manipulate 3D lists.

Creating a 3D List

In the following example, we are going to create a 3D list with the sequential numbers starting from 1.

a, b, c = 2, 2, 3
x = 1
y = []
for i in range(a):
   z = []
   for j in range(b):
      row = []
      for k in range(c):
         row.append(x)
         x += 1
      z.append(row)
   y.append(z)
print("Result :")
print(y)

The output of the above program is as follows -

Result :
[[[1, 2, 3], [4, 5, 6]], [[7, 8, 9], [10, 11, 12]]]

Creating 3D List using Python List Comprehension

The Python list comprehension offers a simple way to create a list using a single line of code. It combines loops and conditional statements, making it efficient compared to the traditional methods of list construction.

Syntax

Following is the syntax of Python list comprehension -

newlist = [expression for item in iterable if condition == True]

In this scenario, we are going to use list comprehension to generate the 3D list.

Example

Let's look at the following example, where we are going to construct a 3D list of size 2*3*4 filled with zeros.

x = 2
y = 3
z = 4
result = [[[0 for _ in range(z)] for _ in range(y)] for _ in range(x)]
print("Result :")
print(result)

The output of the above program is as follows -

Result :
[[[0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0]], [[0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0]]]