This site is retired and is no longer updated since November 2021. Please visit our new website at https://www.teamscode.org for up-to-date information!
Foreach Loops

Foreach loops are for loops specifically designed to be used with arrays, lists, and other data structures. Arrays and Lists - covered in the ArrayLists lesson - have a series of values. Foreach loops will go through the entire series, allowing the user to manipulate each individual value in a systematic way. Here is the syntax:

    for (int x : y) {

        ...

    }

The variable x is the given local variable which represents the current value in the data structure. The variable x must be the same type as the variables stored in the data structure. The variable y calls the data structure.

Here is an application of the foreach loop.

    int[] a = {0,1,2,3,4};

    for (int i : a) { 

        System.out.print(i + 1 + " "); // example code

    }

The above code will print “1 2 3 4 5 “.

You can do something similar with 2D arrays:

    int[][] array = {{1, 2}, {2, 3}, {3, 4}};

    for (int[] arr : array) {

        for (int i : arr) {

            ...

        }

    }

Lesson Quiz

1. On what type of array would the below for each loop work?

    for (int i : j) { }
a. Two dimensional String array
b. One dimensional String array
c. One dimensional int array
d. Two dimensional int array

Written by James Richardson

Notice any mistakes? Please email us at learn@teamscode.com so that we can fix any inaccuracies.