PHP Array


title: array

Introduction to PHP Array

An array can be thought of as a collection of items.

Syntax

An array is defined by array(), or [].

An example of an array in each style can be seen below:

<?php $bikes = array('Suzuki','BMW','Yamaha'); // OR $bikes = ['Suzuki', 'BMW', 'Yamaha'];

Associative array (key => value)

PHP arrays can store more than one type of value at a time:

<?php $arr = array('Suzuki', 3.1415, false, -273);

As you can see there is a string, a float number, a boolean valuea and an integer number.

Arrays can also be defined with named keys, as shown below:

<?php $bikes = [ 'favorite' => 'Suzuki', 'second favorite' => 'BMW', 'not my favorite' => 'Yamaha' ];

Accessing Items

Items within an array can be accessed by their corresponding key, or location within the array.

For instance:

<?php $bikes = ['Suzuki', 'BMW', 'Yamaha']; echo 'I like '. $bikes[0];

Would produce the following output:

I like Suzuki

Another example, using named keys can be seen below:

<?php $bikes = [ 'favorite' => 'Suzuki', 'second favorite' => 'BMW', 'not my favorite' => 'Yamaha' ]; echo 'I like '. $bikes['not my favorite'];

Would produce the following output:

I like Yamaha

Add Item

Is possible to add any item to an existing array.

An example of addition can be seen below:

<?php $bikes = array('Suzuki', 'BMW'); $bikes[] = 'Yamaha';

Another example, using named keys can be seen below:

<?php $bikes = [ 'favorite' => 'Suzuki', 'second favorite' => 'BMW' ]; $bikes['not my favorite'] = 'Yamaha';

Multidimensional Array

As we mentioned earlier arrays are collection of items, often times these items may be arrays of themselves.
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You will always be able to get the value for the specific key by going down the layers: $arr[‘layerOne’][‘two’]

Pitfalls

When working with arrays, there are a few important things to keep in mind:

1) A comma after the last element is optional.
2) Named keys must use quotes to be accessed (i.e. $bikes[not my favorite] would not work).

For more information, please see PHP: Arrays

Length of an Array

The count() function is used to return the length (the number of elements) of an array:

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