140 lines
2.5 KiB
Markdown
140 lines
2.5 KiB
Markdown
---
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title: array
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---
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## Introduction to PHP Array
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An array can be thought of as a collection of items.
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## Syntax
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An array is defined by `array()`, or `[]`.
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An example of an array in each style can be seen below:
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```php
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<?php
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$bikes = array('Suzuki','BMW','Yamaha');
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// OR
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$bikes = ['Suzuki', 'BMW', 'Yamaha'];
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```
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## Associative array (key => value)
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PHP arrays can store more than one type of value at a time:
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```
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<?php
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$arr = array('Suzuki', 3.1415, false, -273);
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```
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As you can see there is a string, a float number, a boolean valuea and an integer number.
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Arrays can also be defined with named keys, as shown below:
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```php
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<?php
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$bikes = [
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'favorite' => 'Suzuki',
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'second favorite' => 'BMW',
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'not my favorite' => 'Yamaha'
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];
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```
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## Accessing Items
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Items within an array can be accessed by their corresponding key, or location within the array.
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For instance:
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```php
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<?php
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$bikes = ['Suzuki', 'BMW', 'Yamaha'];
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echo 'I like '. $bikes[0];
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```
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Would produce the following output:
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```
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I like Suzuki
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```
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Another example, using named keys can be seen below:
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```php
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<?php
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$bikes = [
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'favorite' => 'Suzuki',
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'second favorite' => 'BMW',
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'not my favorite' => 'Yamaha'
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];
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echo 'I like '. $bikes['not my favorite'];
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```
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Would produce the following output:
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```
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I like Yamaha
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```
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## Add Item
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Is possible to add any item to an existing array.
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An example of addition can be seen below:
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```
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<?php
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$bikes = array('Suzuki', 'BMW');
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$bikes[] = 'Yamaha';
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```
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Another example, using named keys can be seen below:
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```
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<?php
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$bikes = [
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'favorite' => 'Suzuki',
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'second favorite' => 'BMW'
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];
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$bikes['not my favorite'] = 'Yamaha';
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```
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## Multidimensional Array
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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']
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## Pitfalls
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When working with arrays, there are a few important things to keep in mind:
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1) A comma after the last element is optional.
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2) Named keys must use quotes to be accessed (i.e. $bikes[not my favorite] would not work).
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For more information, please see [PHP: Arrays](http://php.net/manual/en/language.types.array.php)
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## Length of an Array
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The count() function is used to return the length (the number of elements) of an array:
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<?php
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$cars = array("Volvo", "BMW", "Toyota");
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echo count($cars);
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?>
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