Java equivalent of Python 'in' - for set membership test?
java, membership, python, set
Solution
You can't do it with a straight array, but you can with a `Set<T>` by calling `.contains`. If you feel like you will be doing a lot of `isItemInSet` calls, consider using `Set`s instead of arrays -- you will be much happier.
For example, using a `HashSet<T>` makes `isItemInSet` an O(1) operation (on average). Set insertion and deletion are also similarly fast. Indeed, a `HashSet<T>` in Java is essentially the same as a Python `set()` (similar underlying concept and performance characteristics) -- you will see a big improvement in speed with many calls to query, insert or delete on the set.
Problem
I want to check if an `item` exists in an `item set`. I want to do this in java: ``` def is_item_in_set(item, item_set): return item in item_set ``` I've managed writing this: ``` boolean isItemInSet(String item, String[] itemSet) { for(int i =0; i < itemSet.length; ++i) { if(item.equals(itemSet[i])) { return true; } } return false; } ``` Is there a better way for testing set-membership in Java?