Several methods of initializing a list in Python

This article describes the initialization methods of List in Python and makes a simple comparison of the performance of these methods.

Initialization method

Initialization in this article refers to initializing a list with specific values. For example, to initialize a list with a length of 1000000 with 0, you can use the following methods:

Use loops for initialization

Code:

1
2
3

lst = []
for i in range(1000000):
    lst.append(0)

Use [ value for i in range(length)]

Code:

1	lst = [0 for i in range(1000000)]

Use [value] * length

Code:

1	lst = [0] * 1000000

Performance comparison

Use the following code snippet:

import time

start = time.time()
# ... Different test code
end = time.time()
print("time is: ", (end - start) * 1000)

A simple count of performance can be made, and the result is:

The time of method 1 is: 135 ms
The time of method 2 is: 59 ms
The time of method 3 is: 3 ms

The third method has clear performance advantages.

The above method can also be used to initialize mostly a List, and the initial value can be None.