Say I have an ArrayList with n elements and a HashMap with k elements, is there any faster way than just using a for loop and iterating through each key value of the HashMap?
Map<K, V> yourMap = ...; Collection<K> yourKeys = ...;
you can simply do
keySet() won’t be much faster than writing a loop and calling
remove manually (because that’s basically what it does internally), but it will be simpler to write and read.