  # Initialize a matrix in Python Method # 1: Using an Comprehension List
Comprehension can be thought of as a shorthand for doing this particular operation. In a list comprehension, we can initialize an inner list and then extend that logic again to each line using a list comprehension.

 ` # Python3 demo code ` ` # initialization matrix ` ` # using comprehension list ` ` `  ` # Declaring lines ` ` N ` ` = ` ` 5 `   ` # Column declarations ` ` M ` ` = ` ` 4 ` ` `  ` # using comprehension list ` ` # to initialize coding matrix ` ` res ` ` = ` ` [[` ` 0 ` ` for ` ` i ` ` in ` ` range ` ` (N)] ` ` for ` ` j ` ` in ` ` range ` ` (M)] `   ` # print result ` ` print ` ` (` ` "The matrix after initializing:" ` ` + ` ` str ` ` (res)) `

Output:

The matrix after initializing: [[0, 0, 0, 0, 0], [ 0, 0, 0, 0, 0], [0, 0, 0, 0, 0], [0, 0, 0, 0, 0]]

Method # 2: Using comprehension list + operator "` * `"
This problem can also be simplified with the * operator, which can slightly reduce the time consuming way of doing the task and can just use the multiplication operator to extend the initialization to all N lines.

Output:

The matrix after initializing: [[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 , 0]]

 ` # Python3 demo code ` ` # initialization matrix ` ` # using comprehension list ` ` # and * operator `   ` # Declaring Lines ` ` N ` ` = ` ` 5 `   ` # Column declarations ` ` M ` ` = ` ` 4 ` ` `  ` # using comprehension list ` ` # to init matrix ` ` res ` ` = ` ` [[` ` 0 ` ` for ` ` i ` ` in ` ` range ` ` (M)] ` ` * ` ` N] `   ` # print result ` ` print ` ` (` `" The matrix after initializing: "` ` + ` ` str ` ` (res)) `