Python列表操作 [英] Python list operation

问题描述

我有两个列表 ListA 和 ListB 如下:

ListA=['1','1','2','2','2','3','4','4','5','5','5','5']
ListB=['1','5']

我正在尝试提出长度与 List A 相同的 List C ，但是将 List A 中的数字替换为如果数字在列表B 中，则为'X'.我期望的结果是:

I am trying to come up with List C which has the same length as List A but replace the numbers in the List A with 'X' if the number is in the List B.The result i am expecting:

ListC=['X','X','2','2','2','3','4','4','X','X','X','X']

仅供参考， ListB 的长度将始终小于 ListA 的长度，而 ListB 的长度将不包含任何不在列表A .

FYI, length of ListB will always less than the length of ListA and ListB will not hold any numbers that is not in List A.

我尝试过这样:

ListA=['1','1','2','2','2','3','4','4','5','5','5','5']
ListB=['1','5']
ListC=[]
for items in ListB:
    for a in ListA:
        if items==a:
            ListC.append('X')
        else:
            ListC.append(a)

很显然，这将创建一个列表(具有listB的长度X长度A)，而不只是列表A的长度.是否有任何内置函数可以执行此操作?谁能给我一个提示，怎么做?

obviously this will create a List that has (length of listB X lenght A) rather than just just the length of list A. Is there any built in function that does this operation? Could anyone give me a clue how to do it?

推荐答案

您可以使用列表理解:

[i if i not in ListB else 'X' for i in ListA]

要修复您当前的代码，请使用in检查项目是否在ListB中:

To fix your current code, use in to check to see if the item is in ListB:

for item in ListA:
    if item in ListB:
        ListC.append('X')
    else:
        ListC.append(item)

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