Associative arrays PHP

In PHP, Associative arrays are key and value pairs. where key is any user defined string and value can be of any data type. These keys are used to access values in associative arrays.

Syntax

array_name = array("key"=>value, "key"=>value, "key"=>value);

Key	is used to access value.
Value	is the data, which key holds in associative array.

Create an Associative array

<?php
     // Create an Associative array
     $student = array("name"=>"Vasu", "age"=>17, "class"=>"12th");
?>

Associative array is created using array() function with key=value pairs.

Above example, has $student array variable which holds three key-value pairs, which are explained in below table.

Key	Value
name	Vasu
age	17
class	12th

Access Associative arrays

Associative array can be accessed in two ways

Traversing through loop
with Key directly

Traversing through loop

Access key value

<?php
	$student = array("name"=>"Vasu", "age"=>17, "class"=>"12th");

       foreach ($student as $k => $v) {
  		echo "$k : $v <br>";
	}
?>

Access only Key

<?php
       $student = array("name"=>"Vasu", "age"=>17, "class"=>"12th");

       foreach ($student as  $k => $v) {
  		echo " $k <br>";
	}
?>

Example explained

$student	Is an associative array
$k	Represents all keys in $student array
$v	Represents all related key and its value in $student array

using array_keys() function

<?php
      $student = array("name"=>"Vasu", "age"=>17, "class"=>"12th");

      $keys = array_keys($student);
      foreach ($keys as $k) {
   	 echo $k;
      }
?>

Access only value

<?php
	$student = array("name"=>"Vasu", "age"=>17, "class"=>"12th");

       foreach ($student as $v) {
  		echo " $v <br>";
	}
?>

2) With Key directly

Individual key can be used to accessed value of a particular key in associative array.

<?php
	$student = array("name"=>"Vasu", "age"=>17, "class"=>"12th");
        echo $student["name"] . "<br/>";
        echo $student["age"] . "<br/>";
        echo $student["class"] . "<br/>";
?>

Using for loop

<?php
	// Create an associative array
	$student = array("name"=>"Vasu", "age"=>17, "class"=>"12th");

        $keys = array_keys($student);

	for($i=0; $i < count($keys); $i++) {
		echo $keys[$i] . ' ' . $student[$keys[$i]] . "\n";
       }
?>