如何向列表中的每个元素添加一个整数?

If I have list=[1,2,3] and I want to add 1 to each element to get the output [2,3,4], how would I do that?

如果我有list=[1,2,3]我想给每个元素加1以得到输出[2,3,4]，我该怎么做?

I assume I would use a for loop but not sure exactly how.

我假设我会使用for循环，但不确定具体是如何使用的。

7 个解决方案

#1

new_list = [x+1 for x in my_list]

#2

>>> mylist = [1,2,3]
>>> [x+1 for x in mylist]
[2, 3, 4]
>>>

list-comprehensions python.

python列表理解。

#3

The other answers on list comprehension are probably the best bet for simple addition, but if you have a more complex function that you needed to apply to all the elements then map may be a good fit.

列表理解的其他答案可能是简单加法的最佳选择，但是如果您有一个更复杂的函数，需要应用于所有元素，那么map可能是一个很好的选择。

In your example it would be:

在你的例子中是:

>>> map(lambda x:x+1, [1,2,3])
[2,3,4]

#4

>>> [x.__add__(1) for x in [1, 3, 5]]
3: [2, 4, 6]

My intention here is to expose if the item in the list is an integer it supports various built-in functions.

我的目的是要公开列表中的项是一个整数，它支持各种内置函数。

#5

Python 2+:

Python 2 +:

>>> mylist = [1,2,3]
>>> map(lambda x: x + 1, mylist)
[2, 3, 4]

Python 3+:

Python 3 +:

>>> mylist = [1,2,3]
>>> list(map(lambda x: x + 1, mylist))
[2, 3, 4]

#6

if you want to use numpy there is another method as follows

如果您想使用numpy，还有另一个方法，如下所示

import numpy as np
list1 = [1,2,3]
list1 = list(np.asarray(list1) + 1)

#7

Firstly don't use the word 'list' for your variable. It shadows the keyword list.

首先，不要在变量中使用“list”这个词。它隐藏关键字列表。

The best way is to do it in place using splicing, note the [:] denotes a splice:

最好的方法是用剪接在合适的地方进行，注意[:]表示剪接:

>>> _list=[1,2,3]
>>> _list[:]=[i+1 for i in _list]
>>> _list
[2, 3, 4]