2.6 - Arrays


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    • Today's material is in Replit but it is pasted below as well.


Imagine creating a contact list program. Every contact that gets added is another piece of data that has to go in a variable. But if you don't know how many contacts there will be - how do you know how many variables to make? contact1, contact2, ... contact999?

Instead, we can package data together in one variable - just like packaging characters in a String! Strings are a very special type of variable. They are an array. Almost every programming language in the world has Arrays - at least as an add-on. Arrays let us package multiple values together in one variable. Kind of like a string of letters but instead it could be numbers or booleans or Strings.


// An array of numbers

let someNumbers = [2,4,5,0,-9,5,2,1,2,4];

console.log(someNumbers.length); // 10

One of the biggest differences between Strings and Arrays - you can modify an array.

console.log(someNumbers[1]); // 4

someNumbers[1] = 17;

console.log(someNumbers[1]); // 17

In JavaScript, an Array can contain a mixture of any type of data.

let myArray = ["This is text", 4, 5, true];

We can loop through arrays just like we did with Strings!

for (let i = 0; i < myArray.length; i++)


We can add an element to the end of an existing array with .push()

myArray.push("Some more text");

We can also remove the last element with .pop()

We can declare an empty array:

let myArrayForLater = [];

There are other built-in functions as well, that you can look up online.

Check Replit for your task