Learn the syntax, data types, and operations essential for programming in Scala

Become a Scala Developer

In this module, we will learn Scala from the ground up. This module aims to teach us how to write basic programs, assuming we have no prior knowledge of the language. We will start with a brief introduction to Scala to understand its functionality and applications. We will then move discuss the key features and functions of the language (data types, functions, classes, etc.) in detail. In the end, we will have all the basic knowledge of how to program in Scala.

Learn Scala from Scratch

## Task

In this challenge, you had to create a recursive function `sum` which sums together all the integers in a List.


## Solution

A skeleton of the function was already provided for you. Let's look it over.

```
def sum(numberList: List[Int]): Int = numberList match { 

}
```

`sum` takes a single parameter of type `List[Int]` and returns a value of type `Int`. 

The function body of `sum` consists of a `match` expression. You needed to write the cases required for `sum` to execute correctly. The first case would be our base case which is if the List is empty. In this case, `sum` would return **0**.

```
case Nil => 0
```

The second case is if the List is not empty. In this case, we separate the first element of the List from the rest of the elements using the built-in `::` operator. Let's see how it will work
```
case x :: tail
```
Here the `x` will contain the first element of the list and the `tail` will have all the element of the list except the first element (`x`). Then we will recursively pass the `tail` (a list) to the `sum()` method.
```
case x :: tail => sum(tail)
```

We will continue this process until the base case is reached i.e., the `tail` list becomes empty.




You can find the complete solution below:

>You were required to write the code from **line 1** to **line 4**.

# Task

In this challenge, you had to create a recursive function `sum` which sums together all the integers in a List.


# Solution

A skeleton of the function was already provided for you. Let's look it over.

```
def sum(numberList: List[Int]): Int = numberList match { 

}
```

`sum` takes a single parameter of type `List[Int]` and returns a value of type `Int`. 

The function body of `sum` consists of a `match` expression. You needed to write the cases required for `sum` to execute correctly. The first case would be our base case which is if the List is empty. In this case, `sum` would return **0**.

```
case Nil => 0
```

The second case is if the List is not empty. In this case, we separate the first element of the List from the rest of the elements using the built-in `::` operator. Let's see how it will work
```
case x :: tail
```
Here the `x` will contain the first element of the list and the `tail` will have all the element of the list except the first element (`x`). Then we will recursively pass the `tail` (a list) to the `sum()` method.
```
case x :: tail => sum(tail)
```

We will continue this process until the base case is reached i.e., the `tail` list becomes empty.




You can find the complete solution below:

>You were required to write the code from **line 1** to **line 4**.

In the following lesson, we will go over the solution of the challenge:  Sum of Lists.

Getting to Know Scala

Variables and Types

Operating with Operators

Strings and How to Use Them

Scala's Collection Library

Control Structures

Getting Started with Functions

Higher-Order Functions

Classes and Objects

Conclusion

Solution Review: Sum of Lists

Task

Solution