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PHP Quiz PHP CertificatePHP array_walk() Function
Complete PHP Array Reference
Definition and Usage
The array_walk() function runs each array element in a user-made function. The array's keys and values are parameters in the function. Returns True or False
Syntax
array_walk(array,function,parameter...)
| Parameter | Description |
|---|---|
| array | Required. Specifying an array |
| function | Required. The name of the user-made function |
| parameter | Optional. Specifies a parameter to the user-made function |
Tips and Notes
Tip: You can assign one parameter to the function, or as many as you like.
Note: You can change an array element's value in the user-made function by specifying the first parameter as a reference: &$value. (See example 3)
Example 1
<?php
function myfunction($value,$key)
{
echo "The key $key has the value $value<br />";
}
$a=array("a"=>"Cat","b"=>"Dog","c"=>"Horse");
array_walk($a,"myfunction");
?>
function myfunction($value,$key)
{
echo "The key $key has the value $value<br />";
}
$a=array("a"=>"Cat","b"=>"Dog","c"=>"Horse");
array_walk($a,"myfunction");
?>
The output of the code above will be:
The key a has the value Cat
The key b has the value Dog
The key c has the value Horse
The key b has the value Dog
The key c has the value Horse
Example 2
With a parameter:
<?php
function myfunction($value,$key,$p)
{
echo "$key $p $value<br />";
}
$a=array("a"=>"Cat","b"=>"Dog","c"=>"Horse");
array_walk($a,"myfunction","has the value");
?>
function myfunction($value,$key,$p)
{
echo "$key $p $value<br />";
}
$a=array("a"=>"Cat","b"=>"Dog","c"=>"Horse");
array_walk($a,"myfunction","has the value");
?>
The output of the code above will be:
a has the value Cat
b has the value Dog
c has the value Horse
b has the value Dog
c has the value Horse
Example 3
Change an array element's value. (Notice the &$value)
<?php
function myfunction(&$value,$key)
{
$value="Bird";
}
$a=array("a"=>"Cat","b"=>"Dog","c"=>"Horse");
array_walk($a,"myfunction");
print_r($a);
?>
function myfunction(&$value,$key)
{
$value="Bird";
}
$a=array("a"=>"Cat","b"=>"Dog","c"=>"Horse");
array_walk($a,"myfunction");
print_r($a);
?>
The output of the code above will be:
Array ( [a] => Bird [b] => Bird [c] => Bird )
Complete PHP Array Reference
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