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PHP Tutorial (& MySQL) #7 - Arrays



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alright then gang so now I'd like to

talk about arrays so what are they

exactly

well basically arrays give us a way to

still multiple different values inside

just a single variable so you know how

previously we've created a variable give

it a name like name and set it equal to

a value which could be a string now this

value is being stored inside this

variable right now an array gives us a

way to create multiple different values

and store them all inside a single

variable now in PHP there's three types

of arrays we have indexed arrays

associative arrays and also

multi-dimensional arrays so I'm going to

cover the first two types of array

indexed and associative in this video

right here then in the next video we'll

talk about multi-dimensional so then

indexed arrays first of all these are

the easiest to create and probably

almost the most common as well so

they're very simple to set up all we do

is create a variable I'm going to call

this people one and set it equal to an

array by using square brackets this

indicates an array in PHP so now what we

have to do is place our values inside

these square brackets

so if we're doing an array of strings we

could just do our first string first of

all I'm going to say Shaun is the first

person then we come and separate the

values the second string could be

crystal comment again and the third

string is going to be right okay so now

we have an array here which is storing

three different strings all inside this

one variable now say at some point we

wanted to access one of these different

values inside this array how do we do

that well we do that using the index and

that's why these are called indexed

arrays so you know like when we talked

about strings if we stored a string like

name like so and then we wanted to find

say this letter we'd say name and then

square brackets one because the first

one remember is zero position then this

is one so that would find us the H now

we do a similar thing inside arrays so

instead of this being a string this is

just now an array

and this is position zero this is

position 1 this is 2 and so forth okay

so if we want to access something from

this array we can just use square

brackets to access the index of that

element so for example we'd say people 1

and then 1 and that would get us this

because this is position 0 1 2 ok so

that's why these are called indexed

arrays because we use the index right

here to access them they all have a

specific index associated with them 0 1

2 3 4 5 etc so let's just echo this

through the browser and see if this

works

save that and come over here I'm going

to refresh and we see crystal okay so

that works okay so what I'm going to do

is actually create now another indexed

array called people too

so people too is going to be equal to

square brackets again in fact I'll show

you a different way to create an array

because sometimes you might see this

this is one way to create an indexed

array and that's probably the way I use

most often and another way to create an

array is by saying array and then in

brackets because this is a function this

is going to create an array for us we've

seen functions briefly so they're inside

we place our different values so I could

have an array with Ken and then a

comment again and then the second person

will be Chun - Lee so this here this is

an alternative way to create an array we

use the array keyword the function and

then we place our own values inside

exactly the same way again I probably

use this way more often than not book

you will sometimes see me use this way

as well because I tend to interchange

them okay so let's try this one

we'll say echo and we want people to and

we'll get position I don't know one

again which is this thing right here

because 0 1 okay so let's save that and

preview in a browser and this time we

see Tinley okay so this works as well so

that's two different ways now that we've

seen to create an indexed array now it's

not just limited to adding strings in a

row we can also add other data types as

well for example numbers

so I could create another variable down

here called ages and set that equal to

an array this time using square brackets

and I'll say 20 30 40 50 and now we have

an array of numbers now I want to show

you a different way to print out the

values of these arrays because so far

we've just been echoing out these single

elements inside the array what if we

wanted to echo the whole array well let

me just try this echo

Agis save this and preview over here and

notice a ray to string conversion on

line 12 array so it's basically not

letting us do this because this right

here should be a string whenever we echo

something out it expects an easy

conversion to a string okay then it can

output to the browser so a better way to

see these is to use a function called

print underscore R and that means print

readable so if I save this now it's

going to print a readable version of

this array onto the page over here so if

i refresh now we can see we have an

array position 0 is 21 is 32 is 43 is 50

so this is good if you want to see

what's in an array while you're

developing you can use this print our

function right here and pass in the

array that you want to print to the

screen in a readable format okay cool so

we have these different arrays now what

if we want to maybe change one of the

elements inside one of these arrays well

to do that we use square bracket

notation again so say for example I

wanted to override this age right here

with 25 well this is zero one position

right one so we say ages and then one

and then we set that equal to a new

value so I could say ages one is now

equal to 25 and now if we print our and

then pass in ages this is going to

update and show us that 25 is going to

be in position one this time so save

that refresh and now we can see 25 is in

position 1 ok so that's how we overwrite

a particular value inside

right but what if we want to add a new

value to the array well all we need to

do I'm going to comment this out is say

ages and then square brackets don't put

anything in there and then we could say

60 or something like that and now what's

going to happen is it's going to say

okay well you've not passed in an index

into this array that you want to

overwrite so what I'm going to do is

just add a new element onto the end

which is going to be 60 now so again if

we just print this to the browser we

should see that so save refresh and now

we see 60 on the end cool all right then

now there's another way to add values

onto the end of an array and I'm going

to show you that now I'm going to

comment this out and then I'm going to

say array underscore push which is a

function and this function takes in two

parameters first of all the array that

we want to push a value on to and that

is going to be ages then the second

value is going to be the value that we

want to push onto the array so I'm just

going to say 70 so I'm saying here look

I want to use this array push method to

add on a new element or a new value to

the array at the end and this is the

array I want to add something to and

this is the value I want to add so if I

save this refresh over here then we

don't see anything because we've not

printed it out so let's make sure we do

that save it and refresh now we see this

value added on to the end as well so

that's two different ways we can add

extra values onto an array now I want to

show you one more thing when it comes to

indexed arrays and that is going to be

how to count the different elements

inside it so say I want to know the

length of this thing right here are the

length of this thing then we use a

method called count to do that so I'm

going to echo the result of this to the

browser so echo count and then we're

going to pass in the age or the ages

array and this should be now one two

three four five six because we added

these two on okay so we should see six

in the browser refresh and we see six

cool so that's how we count a

raise and add new items onto the arrays

override them and create them and this

is all one type of array indexed arrays

meaning we use the index of the element

to access them or override them etc okay

so that's the first type of array I

wanted to show you and in fact I'm going

to show you one more thing I'm going to

show you how to merge two arrays

together so say for example we have this

array right here we have this array as

well the both people and we want to

merge them together so we take these

values and we place them onto here into

one gigantic array well we can use a PHP

method to do that as well or a PHP

function rather to do that first of all

I'll create a third variable called

people 3 and that is going to store the

results of this function and the

function name is a r8 underscore merge

then this takes two arguments the first

argument is going to be the first array

we want to merge which is people want

and the second argument is the second

array we want to merge with it which is

people too so now if we print our and

people 3 we should see that merged array

so save that for you in a browser and

now we can see the merged array right

there with every name in it cool ok then

so that's indexed arrays now I'd like to

move on to associative arrays and these

are slightly different but not overly

different so associative arrays are key

value pairs so whereas in an indexed

array we use the index like this to

access the different elements inside the

array this time when we're creating

associative arrays we'll use keys

instead of indexes ok and we'd specify

those keys when we create the arrays so

for example let me just put in brackets

here key and value pairs so we remember

what these are and let's create our

first associative array so I'm going to

create a variable called ninjas 1 and

set that equal to an array right here

now the way we do this is by first of

all creating our key which is normally a

string and this key is going to be the

name of the ninja right and then we do

equals and carrot which

is like an arrow and these points to the

value of whatever this key is going to

be this will all make more sense when we

come to work with it in a second but for

example I'm gonna say black so I'm doing

the ninja name and the belt color so

Shan is a black belt right so this is

the key and this is the value now if we

were looking at indexed the value is

this and the key is this so instead of

the one I'm using now the string Shan

and if we want to access this later on

we're going to use this key to access

the value I hope that makes sense so

that is the first key value pair so we

do a comma after that the second key

value pair is going to be Mario and then

an arrow and then the value which is

going to be orange and sometimes by the

way you might see spaces here really

doesn't matter as long as the arrow is

between the key and the value

so comma and the third one I'm going to

do is Luigi

that's the third key and then an arrow

and the value is going to be brown okay

so that is our first now associative

array okay then so say now I want to

print out this value or echo out this

value to the browser so the way at

access this value is by saying first of

all echo then the variable which is

ninjas one then in square brackets we

use the key which is Mario okay so

inside a string we can't just say Mario

like this it has to be inside the string

inside quotations Mario okay so that

will get us this value which is

associated to that key so let's save

that we should see orange on the screen

and we do cool okay then so again if we

wanted to print a readable version of

this whole array to the browser then we

can just say print underscore R and then

ninjas

want like so save that and preview in a

browser and we see the whole thing so

now we can see the key here and the

value the key the value etc so these

were before zero value one value to

value this time we have keys in

dead of numbers okay cool so let me make

a second associative array I'm going to

call this ninjas two and set this equal

to this time the other way of creating

arrays which is the array function and

we do it exactly the same way inside so

the key first of all then the arrow and

then the value so bowser is going to be

green a green belt and then it will do

peach and peach is going to be yellow

okay so that's our second associative

array now if we want to print this we

can do it exactly the same way prints

are and we'll pass in ninjas to like so

save it and preview in a browser and now

we can see this one as well so we have

Bowser which is green and peach which is

yellow okay cool so let's comment those

out for now and down here and if we

wanted to add a new value to one of

these things then we can do that by just

adding in the new key for example I

could say ninjas - I want to add to this

array right here square brackets I'm

going to make up a key name I'm going to

say toad and I'm going to set that equal

to pink so what that is going to do is

add on here essentially toad pink

okay so we're adding on that new field

that new value so let's get rid of that

and let's print this out now so print

underscore R and ninjas to save it and I

really fresh over here and now we can

see toad is inside the array likewise if

we wanted to override something we could

say peach the value of the key yeah I'm

overriding that with pink so now this

will be pink instead of yellow so save

that preview again and this time we see

that peach is pink etc okay cool so we

can also count the amount of elements or

values inside associative arrays by

using the count function that we also

used before so we pass in the array we

want to count the elements inside of

source a ninja's one and that should be

three right but

we have one two three elements inside

there even though there's six strings

each one of these is just one element so

let's save that preview and we see three

cool okay so we can also merge these

associative arrays much like we did this

thing up here I'm going to just copy

that and I'm going to paste it down here

and this time I'm going to say ninjas 3

is equal to a rate merge that's the

function name and it's going to be equal

to ninjas

1 merged with ninjas too so let's

replace those and finally let's print

this to the screen who's in print are

and ninjas 3 because that's the name of

this variable and that should be the

merged arrays together here so let's

preview that and now we can see we have

this big array Shaun Mario Luigi Bowser

and Peach okay

so there we've got my friends that is

basically in a nutshell indexed arrays

and associative arrays we will be using

these quite frequently as we go forward

and when we make our project later on so

don't worry if you don't understand it

100% just yet we'll be repeating this

many times but in the next video I want

to talk about the third type of a rate

in PHP which is a multi-dimensional

array