php array

PHP Array

Arrays can store multiple values ​​in a single variable:

Example

<?php
 $cars=array("Volvo","BMW","Toyota");
 echo "I like " . $cars[0] . ", " . $cars[1] . " and " . $cars[2] . ".";
 ?>

What is an array?

An array is a special variable that can store multiple values ​​in a single variable.

If you have a list of items (for example: a list of car names), store it into a single variable like this:

$cars1="Volvo";
$ cars2="BMW";
$cars3="Toyota";

However, what if you want to iterate through the array and find a specific one? What if the array has not just 3 items but 300?

The solution is to create an array!

Arrays can store multiple values ​​in a single variable, and you can access the values ​​within them based on their keys.

Creating arrays in PHP

In PHP, the array() function is used to create arrays:

array();

In PHP, There are three types of arrays:

·       Numeric array – an array with numeric ID keys

·        Associative array – an array with specified keys, each key is associated with a value

· Multi-dimensional array-including one or more arrays

# PHP numerical array

Here are two methods to create numerical arrays:

## Automatic allocation ID key (ID keys always start from 0):

$cars=array("Volvo","BMW","Toyota");

Manually assigned ID keys:

$cars[0]="Volvo";

$cars[1]="BMW";
$cars[2]="Toyota";

The following example creates a file named A numeric array of $cars, and allocate three elements to the array, and then print a piece of text containing the array value:

Example

<?php 
$cars=array("Volvo","BMW","Toyota");
 echo "I like " . $cars[0] . ", " . $cars[1] . " and " . $cars[2] . "."; 
 ?>

Get the length of the array - count() function

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

Example

<?php
 $cars=array("Volvo","BMW","Toyota");
 echo count($cars);
 ?>

Traverse the numerical array

Traverse and print all the values ​​in the numeric array, you can use a for loop, as shown below:

Example

<?php
 $cars=array("Volvo","BMW","Toyota");
 $arrlength=count($cars);
 
 for($x=0;$x<$arrlength;$x++)
 {
 echo $cars[$x];
 echo "<br>";
 }
 ?>

PHP Associative Array

Associative arrays are arrays using specified keys that you assign to the array.

There are two ways to create associative arrays:

$age=array("Peter"=>"35","Ben"=>"37","Joe" =>"43");

or:

$age['Peter']="35";

$age['Ben']="37";
$age['Joe']="43";

The specified key can then be used in the script:

Example

<?php
 $age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43");
 echo "Peter is " . $age['Peter'] . " years old.";
 ?>

Traverse the associative array

To traverse and print all values ​​in an associative array, you can use a foreach loop as follows:

Example

<?php
 $age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43");
 
 foreach($age as $x=>$x_value)
 {
 echo "Key=" . $x . ", Value=" . $x_value;
 echo "<br>";
 }
 ?>