JavaScript: Arrays

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Javascript: Arrays

An array is a data structure; e.g. a list of data. Think of var but for multiple information/data, e.g. a list of the names of all your friends (not just one friend - Lord forbid you have only one friend?!).

You can use arrays to structure/organize things, e.g. comments, photos, etc.

Objectives for this issue:

1. Define an array (using codes), remove and add elements arrays
2. Use "push", "pop", "shift", "unshift" --> which are essentially built-in methods

var dogs = ["Rosie", "Max", "Summer", "Hazel"]
console.log(dogs[0]) //"Rosie"

Push and Pop

Push adds another item to end of an array

var writers = ["Joanne Rowling", "David Foster Wallace"]
writers.push("John Williams")
console.log(writers) // "Joanne Rowling", "David Foster Wallace", "John Williams"

Pop takes the last item out, without taking in any argument.

var writers = ["Joanne Rowling", "David Foster Wallace", "John Williams"]
writers.pop() 
console.log(writers) // "Joanne Rowling", "David Foster Wallace"

Unshift and Shift

Unshift adds an item to the front of the array, like so:

var whatever = [...]
whatever.unshift ("thing to add at the front of the list")
console.log(whatever) // "thing to add at the front of the list", "..."

Shift removes an item from the front of array, without taking an argument (just like pop)

var Dwarves = ["Happy", "Sleepy", "Grumpy"] 
Dwarves.shift()
console.log(Dwarves) // "Sleepy", "Grumpy"

indexOf

Basically this will give you the index of an item on the array

var friends = ["Hagrid", "Dumbledore", "Snape"]
friends.indexOf("Hagrid"); //0 

Slice vs Splice

This basically copies whatever you want to copy from an array

var characters = ["Harry Potter", "William Stoner", "Tom Riddle", "Gordon Finch"]
var HarryPotter = characters.slice (0,2) // "Harry Potter", "Tom Riddle"
var AllCharacters = characters.slice ()

Splice is rare - so just google that shit when it comes up on your screen.

REMEMBER: No spacing allowed in var names!

Tadah!