如何檢查多個列表中是否存在變量？

Question

這是我的代碼摘錄！

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))

到目前為止，它僅給出“ False”。 如何檢查多個列表中是否存在變量？ 我試圖在列表內創建列表，但仍然出現“ False”，這是該代碼……

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)

任何幫助，將不勝感激！ ：D謝謝！！！

Answer 1

測試choice是否在any列表中：

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

如果給定可迭代的至少一個元素為真，則any返回True。

choice in ls測試了choice是否為列表的元素。

choice in ls for ls in [division, multiplication, subtraction, addition]是一個生成器理解，這意味着它是一個迭代器，它為[division, multiplication, subtraction, addition]任何可能的ls返回choice in ls的choice in ls結果。

如果這些列表中的一個包含了choice ， any將返回真，否則為false。

Answer 2

您可以使用itertools.chain()來檢查所有列表中的選項，如下所示：

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

Answer 3

現在，您正在將一個字符串選擇與一系列列表進行比較。 當您比較兩種不同的數據類型時，這永遠不會是True。

您應該使用“ in”關鍵字檢查每個列表

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:
.
.
.

這種比較將幫助您在要查找的列表中找到單詞。

Answer 4

如果要檢查選擇是否在示例中提供的四個列表中的任何一個中：

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

Answer 5

現在，您的代碼正在print函數中進行以下比較：

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

由於短路 ，減少到：

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

因為choice不是列表，所以該值始終為False 。

我將對包含[division, multiplication, subtraction, addition]的列表進行[division, multiplication, subtraction, addition]然后測試以查看choice是否在該列表中。

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

print(choice in flattened)

有關在python中扁平化列表列表的更多詳細信息，請參見此 問題的 答案 。