I have a
List<Users>. I want to get the index of the (first) user in the stream with a particular username. I don’t want to actually require the
User to be
.equals() to some described
User, just to have the same username.
I can think of ugly ways to do this (iterate and count), but it feels like there should be a nice way to do this, probably by using Streams. So far the best I have is:
int index = users.stream() .map(user -> user.getName()) .collect(Collectors.toList()) .indexOf(username);
Which isn’t the worst code I’ve ever written, but it’s not great. It’s also not that flexible, as it relies on there being a mapping function to a type with a
.equals() function that describes the property you’re looking for; I’d much rather have something that could work for arbitrary
Anyone know how?
Occasionally there is no pythonic
zipWithIndex in java. So I came across something like that:
OptionalInt indexOpt = IntStream.range(0, users.size()) .filter(i -> searchName.equals(users.get(i))) .findFirst();
Alternatively you can use
zipWithIndex from protonpack library
That solution may be time-consuming if users.get is not constant time operation.