Data Types and Variables

Javascript has 3 basic types of data

• numbers
• strings
• booleans

Let's Practice!!

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Numbers and operators

JavaScript lets you perform basic mathematical operations like addition, subtraction, multiplication, and division. To make these calculations, we use the symbols +, -, *, and /, which are called operators.

Variables

Information or data that changes

var name = "Kenneth";

var myFavoritePokemon = "bulbasaur";

myFavoritePokemon = "Charmander";

var myFavoriteNumber = 12;

var wearsGlasses = true;

Rules for naming Variables

• Variables are Case sensitive
• Must begin with letters, $ or _
• Only contain letters, numbers, $ and _
• Avoid reserved words(<=click to view)
• Make it meaningful
• Use camelCase convention for multipleWords

OK:

    var myPokemon, $myPokemon, _charmander, _Charmander;

Not OK:

    var 3MasterBalls, iBeatTheGymLeader!

Let's Practice

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Excercise 1

How do we write my favorite pokemon in camel case?

Exercise/Problem solving

Find how many seconds is in an hour using variables

Try it for yourself

*Hint*

seconds in a minute is 60 seconds

minutes in an hour is 60 minutes

Now find how many seconds is in 1 hour

Exercise 2 Answer 

var secondsInAMinute = 60;
var minutesInAnHour = 60;
var secondsInAnHour = secondsInAMinute * minutesInAnHour;
secondsInAnHour; 
//The answer is 3600 

Exercise 3

Find your age in 10 years

Try it for yourself

Exercise 3 Anwser

Find your age in 10 years

var age = 10;
var inTenYears = 10;
var myFutureAge = age + inTenYears;
console.log(myFutureAge)
//Answer is 20

Working With Strings

Strings are written within quotes either  “ “ double or ‘ ‘ single

var myFavoriteShow = "Pokemon";

var myFavoriteFood = 'chicken';

Joining Strings

var first = “ken”
var last = “banico”
var fullName = first + last
//output will be "kenbanico"

Try it with your name

Finding Length of a String

"Supercalifragilisticexpialidocious".length; 
34

Try it with your name

Getting a Single Character from a String

var myName = "Ken";
myName[0];
//"K"
myName[1];
//"e"
myName[2];
//“n"

Find The Third Character of your name

Excercise Time

Find The Secret Code

Get the 2nd character of each word and print out the secret code

Hint

var myName = "ken";

myName[0];

"k"

var codeWord1 = “igloo”;
var codeWord2 = “buddy”;
var codeWord3 = “cat”;
var codeWord4 = “umbrella”;

Answer

var codeWord1 = "igloo";
var codeWord2 = "buddy";
var codeWord3 = "cat";
var codeWord4 = "umbrella";
var theSecret = codeWord1[1]+codeWord2[1]+codeWord3[1]+codeWord4[1];
console.log(theSecret);

Try And Make your own secret word

Cutting Strings

Example

var myLongString = "Gotta Catch Em All";
myLongString.slice(6,9);
//Type it out and see what the answer is

Cutting Strings Explaination

var myLongString = "Gotta Catch Em All";
myLongString.slice(6,9);

Start 

End

G o t t a  

0 1 2 3 4    6 7 8 9 10    12 13    15 16 17

C a t c h  

E  M  

A   L   L

Spaces are counted

and does not include the last number you specify

Not Included

Try it out with your own String

Change Strings To All Capital Letters

"Hello there my name is Professer Oak!".toUpperCase();

Example

Type it out

Change Strings To All LowerCase Letters

"hElLo ThERE I liKE POKEMoN".toLowerCase();

Example

Type it out

HARD MODE EXCERCISE

See if you can figure out how to make 

"hElLo ThERE I liKE POKEMoN"

into

"Hello there i like pokemon"

HARD MODE EXCERCISE ANSWER

var complicatedString = "hElLo ThERE I liKE POKEMoN";

//this will get the first firstLetter
var firstLetter = complicatedString[0];

//this will make the firstLetter uppercase
firstLetter = firstLetter.toUpperCase();

//this will get the second letter all the way up to the last letter
var restOfTheString = complicatedString.slice(1)

//this will make the rest of the string toLowerCase
restOfTheString = restOfTheString.toLowerCase();

//we combine the two variables to complete the string
console.log(firstLetter+restOfTheString)