Python IF多个“和”“或”在一个语句中
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Python IF multiple "and" "or" in one statement
提问by yingnan liu
I am just wondering if this following if statement works:
我只是想知道以下 if 语句是否有效：
value=[1,2,3,4,5,f]
target = [1,2,3,4,5,6,f]
if value[0] in target OR value[1] in target AND value[6] in target:
print ("good")
My goal is to make sure the following 2 requirements are all met at the same time: 1. value[6] must be in target 2. either value[0] or value[1] in target Apologize if I made a bad example but my question is that if I could make three AND & OR in one statement? Many thanks!
我的目标是确保同时满足以下 2 个要求： 1. value[6] 必须在目标中 2. 目标中的 value[0] 或 value[1] 如果我做了一个坏例子，请道歉，但是我的问题是，如果我能在一个语句中做三个 AND & OR 吗？非常感谢！
回答by alecxe
Use parenthesisto group the conditions:
使用括号对条件进行分组：
if value[6] in target and (value[0] in target or value[1] in target):
Note that you can make the inlookups in constant time if you would define the targetas a set:
请注意，in如果将 定义target为集合，则可以在恒定时间内进行查找：
target = {1,2,3,4,5,6,f}
And, as mentioned by @Pramod in comments, in this case value[6]would result in an IndexErrorsince there are only 6 elements defined in valueand indexing is 0-based.
而且，正如@Pramod 在评论中提到的，在这种情况下value[6]会导致 an，IndexError因为只有 6 个元素被定义value并且索引是基于 0 的。
