Php-Arrays function-array_key_exists-check whether the given key name or index exists in the array

Array_key_exists () checks whether the given key name or index exists in the array.

[Function]
This function returns a Boolean value,
If the specified key exists in the specified array, true is returned; otherwise, false is returned.
This function can also be used to check whether the specified key is in the object.
Scope of use]
Php4> 4.1.0, php5.
[Use]
Bool array_key_exists (mixed key, array search)
Key/required/key name
Search/required/search Array
[Example]
[Php]
<? Php
$ Search_array = array ('first' => 1, 'second' => 4 );
If (array_key_exists ('first', $ search_array )){
Echo "The 'first' element is in the array ";
}
/*
The 'first' element is in the array
*/

 

Taken from zuodefeng's note