w3resource

PHP foreach Statement

Description

PHP 4 introduced "foreach" construct, it works only on arrays. The foreach looping is the best way to access each key/value pair from an array.

Syntax:

foreach (array_expr as $value)
{
statement
}

array_expr is an array. In every loop the value of the current element of the array is assigned to $value and the internal array pointer is advanced by one and the process continue to reach the last array element.

foreach (array_expr as $key => $value)

{

statement

}

array_expr is an array. In every loop the current element's key is assigned to $key and the internal array pointer is advanced by one and the process continue to reach the last array element.

Example -1 :

In the following example, we define an array with five elements and later we use foreach to access array element's value.

<?php
$fruits = array ("Orange", "Apple", "Banana",  "Cherry", " Mango");
foreach ( $fruits as $value )
{
echo  "$value<br />";
} 
?> 

Output:

Orange
Apple
Banana
Cherry
Mango 

View the example in the browser

Example -2:

In the following example, both the keys and values of an array have accessed (see the second syntax of the foreach statement).

<?php
$personal_details=array("name" => "Rajesh Rao", "occupation" => "Engineer", age => 39, "country" => "India");
foreach ( $personal_details as $key => $value )
{
echo "$key=$value<br />";
}
?>

Output:

name=Rajesh Rao
occupation=Engineer
age=39
country=India

View the example in the browser

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PHP: Tips of the Day

Members of objects or classes can be accessed using the object operator (->) and the class operator (::).

Example:

class MyClass {
 public $a = 1;
 public static $b = 2;
 const C = 3;
 public function d() { return 4; }
 public static function e() { return 5; }
}
$object = new MyClass();
var_dump($object->a); // int(1)
var_dump($object::$b); // int(2)
var_dump($object::C); // int(3)
var_dump(MyClass::$b); // int(2)
var_dump(MyClass::C); // int(3)
var_dump($object->d()); // int(4)
var_dump($object::d()); // int(4)
var_dump(MyClass::e()); // int(5)
$classname = "MyClass"; 
var_dump($classname::e()); // also works! int(5)

Note that after the object operator, the $ should not be written ($object->a instead of $object->$a). For the class operator, this is not the case and the $ is necessary. For a constant defined in the class, the $ is never used.

Also note that var_dump(MyClass::d()); is only allowed if the function d() does not reference the object:

class MyClass {
 private $a = 1;
 public function d() {
 return $this->a;
 }
}
$object = new MyClass();
var_dump(MyClass::d()); // Error!

This causes a 'PHP Fatal error: Uncaught Error: Using $this when not in object context'

These operators have left associativity, which can be used for 'chaining':

class MyClass {
 private $a = 1;

 public function add(int $a) {
 $this->a += $a;
 return $this;
 }

 public function get() {
 return $this->a;
 }
}
$object = new MyClass();
var_dump($object->add(4)->get()); // int(5)

These operators have the highest precedence (they are not even mentioned in the manual), even higher that clone. Thus:

class MyClass {
 private $a = 0;
 public function add(int $a) {
 $this->a += $a;
 return $this;
 }
 public function get() {
 return $this->a;
 }
}
$o1 = new MyClass();
$o2 = clone $o1->add(2);
var_dump($o1->get()); // int(2)
var_dump($o2->get()); // int(2)

The value of $o1 is added to before the object is cloned!

Note that using parentheses to influence precedence did not work in PHP version 5 and older (it does in PHP 7):

// using the class MyClass from the previous code
$o1 = new MyClass();
$o2 = (clone $o1)->add(2); // Error in PHP 5 and before, fine in PHP 7
var_dump($o1->get()); // int(0) in PHP 7
var_dump($o2->get()); // int(2) in PHP 7