arrays.md

Exercise Set 5: Arrays

These exercises are to deepen you understanding of the array data type, but the previous knowledge is still very relevant and will be used here as well.

Exercise 17

Trying out different Array functions

Arrays are a more complex data type and you interact with them mostly through functions. This is different to for example a number, which can be added to another number through +, or a boolean which has operations like || and &&.

For example one function is called reverse. It allows you to, well, reverse an array, like this:

> [10,20,30].reverse()
[ 30, 20, 10 ]

This task asks you to try the following array functions. Figure out how they work and what they do:

• push/ unshift
• pop / shift
• includes
• slice
• join

Hint: Make heavy use of online documentation like MDN here.

Exercise 18

Calculate the number of full aged people.

You are given a list of ages, like this:

let ages = [21, 12, 16, 34, 18, 21, 22, 15, 25, 30];

Count (by using a javascript program, of course), how many of these 10 people are younger than 18.

Hints

• Use a for loop to iterate through the values of an array
• declare a variable (or more) outside the loop to keep track of the count(s)