Arrays
What's an array, you say?
An array is a special kind of variable that can store multiple values in a single variable.
<?php $friends = array(); ?>
Huzzah! We just created an array with array(), the so-called array constructor.
Values
An empty array doesn't really serve a purpose, though. How about we give $friends some values?
<?php
$friends = array("Caroline", "Max");
?>Great! We can create an array with values by putting them in the parentheses of array().
Accessing
But how can we access the contents of an array?
<?php
$friends = array("Caroline", "Max");
echo $friends[0];
?>//Output Below
Caroline
That's it! We can access a value by putting its position in brackets after the array's name.
Psst: this position is zero-based, which means that it starts at 0.
Adding
We can also add values to an array. Let's add something to $friends, shall we?
<?php
$friends = array("Caroline", "Max");
$friends[] = "Earl";
?>Nice! We can add a value by giving it to the array with brackets but without a position.
Replacing
Now that we know how to add values, how might we be able to replace one?
<?php
$friends = array("Caroline", "Max");
$friends[1] = "Chestnut";
var_dump($friends);
?>//Output Below
array(2) {
[0]=>
string(8) "Caroline"
[1]=>
string(8) "Chestnut"
}Fantastic! We can replace a value by storing a new value at a position that already exists.
Psst: var_dump() is a so-called function that displays information about a variable. It allows us to see the whole array.
Counting
We can find out the number of items in an array as well. How might we do this?
<?php
$friends = array("Caroline", "Max");
echo count($friends);
?>//Output Below
2
Sweet! We can use the count() function to find out how many values an array has.
Sorting
We can also sort an array. Let's add some more values and get $friends in alphabetical order!
<?php
$friends = array("Caroline",
"Max", "Earl", "Oleg", "Han");
sort($friends);
var_dump($friends);
?>//Output Below
array(5) {
[0]=>
string(8) "Caroline"
[1]=>
string(4) "Earl"
[2]=>
string(3) "Han"
[3]=>
string(3) "Max"
[4]=>
string(4) "Oleg"
}Right on! The sort() function orders the items of an array in ascending order, be they numbers or strings.
Psst: another function called rsort() sorts an array in descending order.
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