You can use enhanced loops in Java to achieve the same results as a for
loop. An enhanced loop is also known as a for-each
loop in Java.
Enhanced loops simplify the way you create for
loops. They are mostly used to iterate through an array or collection of variables.
In this tutorial, you'll learn the syntax and how to use the for-each
loop (enhanced loop) in Java.
Java For-Each Loop Syntax
Here's what the syntax of a for-each
loop in Java looks like:
for(dataType variable : array) {
// code to be executed
}
In the syntax above:
- dataType denotes the data type of the array.
- variable denotes a variable assigned to each element in the array during the iteration (you'll understand this through the examples that follow).
- array denotes the array to be looped through.
Java For-Each Loop Example
Let's take a look at some examples to help you understand how a for-each
loop works.
Java For-Each Loop Example #1
class ForEachExample {
public static void main(String[] args) {
int[] even_numbers = { 2, 4, 6, 8 };
for(int number : even_numbers){
System.out.println(number);
// 2
// 4
// 6
// 8
}
}
}
In the code above, we created an array called even_numbers
.
To loop through and print all the numbers in the array, we made use of a for-each
loop: for(int number : even_numbers){...}
.
In the parenthesis for the loop, we created an integer variable called number
which would be used to loop through the even_numbers
array.
So, for:
Iteration #1
number
= first element in the array (2). This gets printed out.
Iteration #2
number
= second element in the array (4). This current value gets printed out.
Iteration #3
number
= third element in the array (6). This current value gets printed out.
Iteration #4
number
= fourth element in the array (8). This current value gets printed out.
The value of number
keeps changing to the current index during the iteration process until it gets to the end of the array. After each index is printed out, it moves to the next index.
You can also see it this way: "For every number
in the even_numbers
array, print number
)".
Java For-Each Loop Example #2
class ForEachExample {
public static void main(String[] args) {
int[] even_numbers = { 2, 4, 6, 8 };
for(int number : even_numbers){
number = number*2;
System.out.println(number);
}
}
}
In the code above, we're multiplying the value of each element by two using the number
variable: number = number*2;
.
The process here is the same with the last example. When number
becomes an element in the array, it doubles the element's value and prints it to the console.
Summary
You can use for-each
loops in Java to iterate through elements of an array or collection.
They simplify how you create for
loops. For instance, the syntax of a for
loop requires that you create a variable, a condition that specifies when the loop should terminate, and an increment/decrement value.
With for-each
loops, all you need is a variable and the array to be looped through.
But this doesn't mean that you should always go for for-each
loops.
for
loops give you more control over what happens during the iteration process – controlling and tracking what happens at every index or some indexes.
On the other hand, for-each
loops can be used when you have no use for tracking each index. The code just runs through for every element in the array.
You can learn more about for
loops in Java by reading this article.
Happy coding!