Part-13-For-Loops.md

Part 13: For Loops

Table of Contents
13-1: Creating For Loops
13-2: Looping Through a Range
13-3: If - Else If - Else

Creating For Loops

Let's create a new file in our text editor (mine is named "scala_for_loops.scala"). We'll create a new list called "badgers".

var badgers = List("mushroom", "mushroom", "it's a snake")

Now, we'll create a "for loop" using this list.

input

for(item <- badgers){
    println("BADGER!")
}

As in the last section, mark sure to launch your spark-shell in your text editor. Run your file.

:load scala_for_loops.scala

And now we get our badgers!

output

BADGER!
BADGER!
BADGER!

We can also print each individual item in the list.

input

for(item <- animals){
    println(item)
}

output

mushroom
mushroom
it's a snake

Looping Through a Range

Next, let's use a "for loop" to loop through a range. We'll use the "Array.range(start, stop, step)" format to create a range from 0 to 20. In Scala (as in other programming languages), remember that this range will go up to but not include 20. We can also use a step argument; I'll use 5 as our step, so we'll return every 5th number.

input

for(number <- Array.range(0,20,5)){
    println(number)
}

output

0
5
10
15

If Statement Embedded Within For Loop

Let's create an if-else statement embedded within a for loop. We create a range of 0 to 10 and print whether the number is odd or even.

input

for(num <- Range(0,10)){
    if(num%2 == 0){
        println(s"$num is even")
    }else{
        println(s"$num is odd")
    }
}

output

0 is even
1 is odd
2 is even
3 is odd
4 is even
5 is odd
6 is even
7 is odd
8 is even
9 is odd

Finally, let's revive our animals list.

var animals = List("aardvark", "hedgehog", "walrus")

input

for(word <- animals){
    if(word.startsWith("a")){
        println(s"$word starts with a a")
    }
}

output

aardvark starts with a a

Project Table of Contents

Part 1: Installation, Set-Up, and "Hello World"
Part 2: Data Types
Part 3: Arithmetic Operators
Part 4: Variables vs Values
Part 5: String Operations
Part 6: Tuples
Part 7: Lists
Part 8: Arrays
Part 9: Sets
Part 10: Maps
Part 11: Logical Operators
Part 12: If Statements
Part 13: For Loops
Part 14: While Loops
Part 15: Functions