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= Foreach As =

=== Description ===

Loop based on an expression.

<pre>
foreach( <expression> as <value> )
{
    statements
    ...
}
</pre>

=== Parameters ===

==== expression  ====

An expression to use could equal an array, string, whatever.

==== value  ====

The value to place the result in most common as a $variable.

=== Remarks ===

For...As statements may be nested.

If the expression contains an array the loop will cycle through each element in the array.

If the expression contains a string or numbers it will cycle through each char.

It is a bad idea to try edit the array while you are loop through it... Strange things may happen including hard crashes.

If you wish to edit an array as you loop through it check out [[Core Function Each|Each( <array> )]] command see its examples one of them should tell you how to do this.

=== Example ===

Here we cycle through binary data :

<syntaxhighlight lang="sputnik">
$binary = Pack("ifz0", (int)100, (float)777.42, "Hello");
foreach( $binary as $item )
{
	println( 
			"Index '" . DecPad($item, 3) . "' " . 
			"Dec '$item' " .  
			"Hex '" . Hex($item) . "' " . 
			"Char '" . Chr($item) . "'"
			);
}
</syntaxhighlight>

Here we cycle through an array :

<syntaxhighlight lang="sputnik">
$arr = array( 2, 4, 6, 8, 10 );
foreach( $arr as $item )
{
	println("Value is $item");
}
</syntaxhighlight>

Here we cycle through each char in a string :

<syntaxhighlight lang="sputnik">
$arr = "Hello World";
foreach( $arr as $item )
{
	println("Value is $item");
}
</syntaxhighlight>

Here we cycle through each letter in a float :

<syntaxhighlight lang="sputnik">
$arr = 777.42;
foreach( $arr as $item )
{
	println("Value is $item");
}
</syntaxhighlight>

You can also referance when using arrays using the pointer & operator for example :

<syntaxhighlight lang="sputnik">
$arr = array( 2, 4, 6, 8, 10 );
foreach( $arr as & $item )
{
	println("Value is $item"); // Prints 2 4 6 8 10
	*$item *= 2;
	// notice the * before $item? this tells Sputnik
	// to resolve the Pointer and get the real value
	// then we can modify it
}
println("");
foreach( $arr as $item )
{
	println("Value is $item"); // Prints 4 8 12 16 20
}
</syntaxhighlight>

See the & before $item on the first loop? This causes $item to actually LINK to the real element inside the array so changing $item will change the item in the array.

This can be seen by printing the array after changing it in the example.

Note - You can only change elements in an array! This will not work with anything else.

A reverse foreach

<syntaxhighlight lang="sputnik">
println("Value $i") foreach("Hello world" as $i);
</syntaxhighlight>

Example of unpacking nested arrays with list()

<syntaxhighlight lang="sputnik">
$array = array(
    array(1, 2),
    array(3, 4)
);

foreach ($array as list($a, $b)) 
{
    // $a contains the first element of the nested array,
    // and $b contains the second element.
    echo "A: $a; B: $b\n";
}
// Prints
// A: 1; B: 2
// A: 3; B: 4
</syntaxhighlight>

Another example of unpacking nested arrays with list()

<syntaxhighlight lang="sputnik">
$array = array(
    array(1, 2, 3, 4),
    array(5, 6, 7, 8)
);
 
foreach ($array as list($a, $b, $c, $d)) 
{
    // $a contains the first element of the nested array,
    // and $b contains the second element.
    echo "A: $a; B: $b; C: $c; D: $d\n";
}
// Prints
// A: 1; B: 2; C: 3; D: 4
// A: 5; B: 6; C: 7; D: 8
</syntaxhighlight>

Yet another example of unpacking nested arrays with list() however this one only works if there is only 1 element in each array (key, value) and it must be a hash and not numeric (like normal arrays)

<syntaxhighlight lang="sputnik">
$array = array(
    array("Cat" => "Meow"),
    array("Dog" => "Woof"),
    array("Foo" => "Bar")
);

foreach ($array as list($key, *$value)) 
{
    // $a contains the first element of the nested array,
    // and $b contains the second element.
    echo "Key: $key | Value: $value\n";
}
// Prints
// Key: Cat | Value: Meow
// Key: Dog | Value: Woof
// Key: Foo | Value: Bar
</syntaxhighlight>

Looping a .NET array

<syntaxhighlight lang="sputnik">
use("System");

$chars = %Char[]->new(3);
$chars[0] = 'A';
$chars[1] = 'B';
$chars[2] = 'C';

say "Printing";
foreach($chars as $c)
{
	say $c;
}
// Printing
// A
// B
// C
</syntaxhighlight>

Looping a .NET array as a ref to modify its values in real time

<syntaxhighlight lang="sputnik">
use("System");

$chars = %Char[]->new(3);
$chars[0] = 'A';
$chars[1] = 'B';
$chars[2] = 'C';

say "Printing";
foreach($chars as &$c)
{
	say $c;
	*$c = 'T';
}

say "Printing modified array";
foreach($chars as $c)
{
	say $c;
}
// Printing
// {REF}:A
// {REF}:B
// {REF}:C
// Printing modified array
// T
// T
// T
</syntaxhighlight>
[[Category:Core Function]]