Syntax sugar for querying a Python list which element occurs first

Question

I have a list of many elements.

I care about two of its elements, a and b.

I don't know the order of the list, nor do I want to sort it.

Is there a nice one-liner that will return True if a occurs before b and false otherwise?

Answer 1

In the interests of diversity, you could also:

b in l[l.index(a):]

This will be True if a == b. If you know that a != b,

b in l[l.index(a) + 1:]