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) { }
Written by James Richardson
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