如何检查多个列表中是否存在变量？

Question

这是我的代码摘录！

division = ["Division","Divide","/","div"]
multiplication =["*","x","times","multiply","multiplication","multiple"]
subtraction = ["-",'minus','subtract','subtraction']
addition = ['+','plus','addition','add']
root = ['root','squareroot','square root']
square = ['square','squared','power 2']

choice = input('calculation type')
print(choice == (division or multiplication or subtraction or addition))

到目前为止，它仅给出“ False”。 如何检查多个列表中是否存在变量？ 我试图在列表内创建列表，但仍然出现“ False”，这是该代码……

division = ["Division","Divide","/","div"]
multiplication = ["*","x","times","multiply","multiplication","multiple"]
subtraction = ["-",'minus','subtract','subtraction']
addition = ['+','plus','addition','add']
root = ['root','squareroot','square root']
square = ['square','squared','power 2']
basic_double = [division,multiplication,subtraction,addition]
basic_single = [root,square]
choice = input('calculation type')
print(choice == basic_double or basic_single)

任何帮助，将不胜感激！ ：D谢谢！！！

Answer 1

测试choice是否在any列表中：

any(choice in ls for ls in [division, multiplication, subtraction, addition])

如果给定可迭代的至少一个元素为真，则any返回True。

choice in ls测试了choice是否为列表的元素。

choice in ls for ls in [division, multiplication, subtraction, addition]是一个生成器理解，这意味着它是一个迭代器，它为[division, multiplication, subtraction, addition]任何可能的ls返回choice in ls的choice in ls结果。

如果这些列表中的一个包含了choice ， any将返回真，否则为false。

Answer 2

您可以使用itertools.chain()来检查所有列表中的选项，如下所示：

if choice in chain(division, multiplication, subtraction, addition):

Answer 3

现在，您正在将一个字符串选择与一系列列表进行比较。 当您比较两种不同的数据类型时，这永远不会是True。

您应该使用“ in”关键字检查每个列表

if choice in division:
     #this returns true if the String set to choice is in the list of objects in division.
else if choice in multiplication:
.
.
.

这种比较将帮助您在要查找的列表中找到单词。

Answer 4

如果要检查选择是否在示例中提供的四个列表中的任何一个中：

if choice in division + multiplication + subtraction + addition:
   # do something when its in any of it.
   ...

Answer 5

现在，您的代码正在print函数中进行以下比较：

choice == ["Division","Divide","/","div"] or ["*","x","times","multiply","multiplication","multiple"] or ["-",'minus','subtract','subtraction'] or ['+','plus','addition','add']

由于短路 ，减少到：

choice == ["Division","Divide","/","div"]

因为choice不是列表，所以该值始终为False 。

我将对包含[division, multiplication, subtraction, addition]的列表进行[division, multiplication, subtraction, addition]然后测试以查看choice是否在该列表中。

flattened = [item for ls in [division, multiplication, subtraction, addition] for item in ls]

print(choice in flattened)

有关在python中扁平化列表列表的更多详细信息，请参见此 问题的 答案 。