Introduction
In this article I describe the PHP array functions array_key_exists, array_keys and array_map. To learn some other math functions, go to:
- Array Functions in PHP: PART 1
- Array Functions in PHP: PART 2
- Array Functions in PHP: PART 3
- Array Functions in PHP: PART 4
- Array Functions in PHP: PART 5
- Array Functions in PHP: PART 6
PHP array_key_exists Function
The PHP array_key_exists function deterimes whether the specified key or index exists in the given array or not and returns true if it exists otherwise false.
Syntax
array_key_exists(key, array) |
Parameters
The parameters of the array_key_exists function are:
Parameter |
Description |
key |
It specifies key. |
array |
It specifies an array. |
Example
An example of the array_key_exists function is:
<?php
echo "<pre>";
$val = array("a" => "Apple", "b" => "Mango", "c" => "Orange", "Banana");
if(array_key_exists("a",$val))
{
echo "Key exists!";
}
else
{
echo "key does not exists!";
}
?>
Output
PHP array_keys Function
The PHP array_keys function accepts an array and returns a new array that contains only its keys.
Syntax
Parameters
The parameters of the array_keys function are:
Parameter |
Description |
array |
It specifies an array. |
values |
It specifies values, then only keys with this values are returned. |
Example
An example of the array_keys function is:
<?php
echo "<pre>";
$val = array("a" => "Apple", "b" => "Mango", "c" => "Orange", "Banana");
echo "Without Value Parameter: ";
print_r(array_keys($val));
echo "<pre>";
echo "With Value Parameter: ";
print_r (array_keys($val,"Mango"));
?>
Output
PHP array_map function
The array_map function sends each value of an array to the user-defined function and returns an array containing all the elements of arr1 after applying the user-defined function to each one.
Syntax
array_map( userDefinedFunction, array1, array2,........................) |
Parameters
The parameters of the array_map function are:
Parameter |
Description |
userDefinedFunction |
It specifies name of user defined function. |
array1 |
It specifies an array. |
array2 |
It specifies an array. |
Example
An example of the array_map function is:
<?php
function myfunction($array1)
{
if ($array1==="Mango")
{
return "orange";
}
return $array1;
}
$array1 = array(1 => "Apple", 2=> "Mango", 3 => "Orange", "Banana");
echo "<pre>";
$result = array_map("myfunction",$array1);
print_r($result);
?>
Output