如何将列表中的每个元素乘以一个数字?

问题描述：

我有一个列表:

my_list = [1, 2, 3, 4, 5]

如何将my_list中的每个元素乘以5?输出应为:

How can I multiply each element in my_list by 5? The output should be:

[5, 10, 15, 20, 25]

答

您可以只使用列表推导:

You can just use a list comprehension:

my_list = [1, 2, 3, 4, 5]
my_new_list = [i * 5 for i in my_list]

>>> print(my_new_list)
[5, 10, 15, 20, 25]

请注意，列表理解通常是执行for循环的更有效方法:

Note that a list comprehension is generally a more efficient way to do a for loop:

my_new_list = []
for i in my_list:
    my_new_list.append(i * 5)

>>> print(my_new_list)
[5, 10, 15, 20, 25]

作为替代方案，以下是使用流行的Pandas软件包的解决方案:

As an alternative, here is a solution using the popular Pandas package:

import pandas as pd

s = pd.Series(my_list)

>>> s * 5
0     5
1    10
2    15
3    20
4    25
dtype: int64

或者，如果您只想要列表:

Or, if you just want the list:

>>> (s * 5).tolist()
[5, 10, 15, 20, 25]