如果一个值等于值列表中的一个，是否有一种方法可以让 If 语句返回真 Python

Question

Is there a way to do something like this in python, where if a value is equal to one of a set of values, the if statement returns true (without using or and then replicating the first expression and the condition)?

li1 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
li2 = []
for n in li1:
    if n == 2, 3, 5, 8:
        li2.append(n)

This was an example without list comprehension but I want to have something like this with list comprehension, considering the whole point of it is to make code shorter.

li = [int + 1 for int in range(10) if int == 2, 3, 5, 8]

But I haven't found anything that could do this. I know you can use or and do something like this,

li = [int + 1 for int in range(10) if int + 1 == 2 or int + 1 == 3 or int + 1 == 5 or int + 1 == 8]

but it just seems lengthy. I've tried a lot of things like using lists, tuples, range() , or (without copying the first expression and the condition), etc. It either just says invalid syntax or doesn't do the right thing. I don't really know how to phrase the question, so I can't use a google search.

If anyone knows whether or not this can be done, thank you in advance: :)

Answer 1

There are multiple ways to do that.
One would be to use if int in [2, 3, 5, 8] . Basically this: li = [int + 1 for int in range(10) if int in [2, 3, 5, 8]]

Or of course just this: li = [int + 1 for int in [2, 3, 5, 8]]

You can also use lambdas, if you want to have a more complex condition:
li = [int + 1 for int in range(10) if (lambda x: x % 3 == 0)(int)]
You would not need a lambda for that, but this tests if your int is a multiple of three.

Some thought about lambdas: Here the lambda does not really make sense as you could just write int % 3 == 0 without the lambda. I don't want to go into detail about lambdas, as this would be out of scope. So if you want some great examples on how/when to use them, have a look at this answer .

This if n == 2, 3, 5, 8 on the other hand is not valid python.

Additional:
int is a built-in which should not be used as a variable name. Even if it is syntactically correct.

Answer 2

li = [int + 1 for int in range(10) if int + 1 in [2, 3, 5, 8]]