foreach: A Collection Method

Introduction

As this chapter deals with collections, it is important to know how to print the elements in a collection.

We cannot simply use println or print as they are used to print single values and collections are a collection of values. For this reason, Scala provides the foreach method. This method can be used by every instance of every class in the collection library.

Syntax

The foreach method is called on a collection of any type and takes a single argument. The argument must be a function/method that will be applied to each individual element of the collection.

For printing the elements of a collection, we would need to apply the println or print method to each element.

In the above code, we are calling foreach on collection and passing the println method. When you press RUN, you will see all the elements of collection printed on the console.

What is happening is that foreach is traversing over collection. It first goes to the first element of collection, i.e., 2 and applies the println method on it. This results in the printing of 2. foreach then goes to the second element of collection, i.e., 4 and performs the println method on it. This results in the printing of 4. This continues until foreach has traversed through all the elements of collection.

In the next lesson, we will move on to the first collection: Arrays.