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2016/01/06

PHP arrays - simple operations

Source: Flickr.com -  Upupa4me
Like all things in life, we need to start with simple things. So, in order to understand what arrays are in PHP, we need to take a look at the PHP manual to read what it is all about:
An array in PHP is actually an ordered map. A map is a type that associates values to keys. This type is optimized for several different uses; it can be treated as an array, list (vector), hash table (an implementation of a map), dictionary, collection, stack, queue, and probably more.
The thing with PHP is that an array is probably one of the most used data structures in web applications build with PHP and used for a wide variety of purposes.

Let's look at a first usage of an array: storing multiple values in a list.

<?php
$array 
= [
    
'foo',
    
'bar',
    
'baz',
];


This is a PHP array with 3 elements. Now we can add an element at the end of this array.

// Adding an element at the of the array 
array_push($array'foobar');

Or even more efficient:

$array[] = 'barbaz';

Now our array looks like this:

$array = [
    
'foo',
    
'bar',
    
'baz',
    
'foobar',
    
'barbaz',
];


As you can see, PHP arrays are easy to create lists which you can now toss around in your application. But what if you need to reverse the process and remove elments from the end of your array?

// Removing the last element of an array 
$last array_pop($array);

Now $last will contain the value "barbaz" and the array itself is now reduced by one from the end.

$array = [
    
'foo',
    
'bar',
    
'baz',
    
'foobar',
]; 


Of course we can also pull elements from the beginning of the array.

// Removing the first element of an array 
$first array_shift($array); 

Now $first will contain the value "foo" and the array is now reduced by one from the beginning.

$array = [
    
'bar',
    
'baz',
    
'foobar',
]; 


In our next chapter let's have a look at associative arrays and what you can do with those.