You can find many methods to perform this task, let me help you with a few:
>>> help(["foo", "bar", "baz"])
Help on list object:
| L.index(value, [start, [stop]]) -> integer -- return first index of value
This method is quite useful and lead to the method you are looking for.
indexes = [i for i,y in enumerate(ys) if y == 'asd']
If you have any doubts, put them down below in the comments, cheers.