Is there a Java equivalent of Python's 'enumerate' function?

Question

In Python, the enumerate function allows you to iterate over a sequence of (index, value) pairs. For example:

>>> numbers = ["zero", "one", "two"] >>> for i, s in enumerate(numbers): ...     print i, s ...  0 zero 1 one 2 two 

Is there any way of doing this in Java?

Answer 1

For collections that implement the List interface, you can call the listIterator() method to get a ListIterator. The iterator has (amongst others) two methods - nextIndex(), to get the index; and next(), to get the value (like other iterators).

So a Java equivalent of the Python above might be:

import java.util.ListIterator;   import java.util.List;  List<String> numbers = Arrays.asList("zero", "one", "two"); ListIterator<String> it = numbers.listIterator(); while (it.hasNext()) {     System.out.println(it.nextIndex() + " " + it.next()); } 

which, like the Python, outputs:

0 zero 1 one 2 two