PHP gets the position of an element in an array and the array_keys function is applied

As we all know, PHP has many built-in functions, which is one of the important reasons that using PHP can greatly improve the development efficiency. There are many ways to get the position of the 1 element in an array, among which PHP itself has a built-in function array_keys(). The following code can print out all the built-in functions of PHP:

 
<?php 
print_r(get_defined_functions()); 
?> 

The syntax for array_keys is as follows:

 
array_keys(array,value,[strict]) 

Where strict is set to true to trigger the strict matching mode of data type validation, the default is false. The following code shows a simple application of array_keys.

 
<?php 
$test=array(10,20,30,"10","20","30"); 
print_r(array_keys($test,"10",true));// Strict matching pattern  
// Output:  
//Array ( [0] => 3) 
?>