Unleash the potential of PHP foreach
loop with practical examples. Master seamless iteration through arrays, enhancing code efficiency in web development.
The foreach
loop - Loops through a block of code for each element in an array or each property in an object.
The most common use of the foreach
loop, is to loop through the items of an array.
Loop through the items of an indexed array:
$colors = array("red", "green", "blue", "yellow");
foreach ($colors as $x) {
echo "$x <br>";
}
For every loop iteration, the value of the current array element is assigned to the variabe $x
. The iteration continues until it reaches the last array element.
The array above is an indexed array, where the first item has the key 0, the second has the key 1, and so on.
Associative arrays are different, associative arrays use named keys that you assign to them, and when looping through associative arrays, you might want to keep the key as well as the value.
This can be done by specifying both the key and value in the foreach
defintition, like this:
Print both the key and the value from the $members
array:
$members = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"43");
foreach ($members as $x => $y) {
echo "$x : $y <br>";
}
The foreach
loop can also be used to loop through properties of an object:
Print the property names and values of the $myCar
object:
class Car {
public $color;
public $model;
public function __construct($color, $model) {
$this->color = $color;
$this->model = $model;
}
}
$myCar = new Car("red", "Volvo");
foreach ($myCar as $x => $y) {
echo "$x: $y <br>";
}
With the break
statement we can stop the loop even if it has not reached the end:
Stop the loop if $x
is "blue":
$colors = array("red", "green", "blue", "yellow");
foreach ($colors as $x) {
if ($x == "blue") break;
echo "$x <br>";
}
With the continue
statement we can stop the current iteration, and continue with the next:
Stop, and jump to the next iteration if $x
is "blue":
$colors = array("red", "green", "blue", "yellow");
foreach ($colors as $x) {
if ($x == "blue") continue;
echo "$x <br>";
}
When looping through the array items, any changes done to the array item will, by default, NOT affect the original array:
By default, changing an array item will not affect the original array:
$colors = array("red", "green", "blue", "yellow");
foreach ($colors as $x) {
if ($x == "blue") $x = "pink";
}
var_dump($colors);
BUT, by using the &
character in the foreach
declaration, the array item is assigned by reference, which results in any changes done to the array item will also be done to the original array:
By assigning the array items by reference, changes will affect the original array:
$colors = array("red", "green", "blue", "yellow");
foreach ($colors as &$x) {
if ($x == "blue") $x = "pink";
}
var_dump($colors);
The foreach
loop syntax can also be written with the endforeach
statement like this
Loop through the items of an indexed array:
$colors = array("red", "green", "blue", "yellow");
foreach ($colors as $x) :
echo "$x <br>";
endforeach;
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