056 - array_keys (return the key of an array
Array
(
    [0] => 0
    [1] => 1
    [2] => 2
    [3] => 3
)

Array
(
    [0] => first
    [1] => second
    [2] => third
    [3] => fourth
)
array_key_first 
first
array_key_last
fourth
array_key_exists
1
array_key_exists
key_exists 
1
Key exists!



    <?php
// 056 - array_keys (return the key of an array 
       echo "</br><span class='myheading'>056 - array_keys (return the key of an array</span></br>";

       $color_056 =["red","green","blue","yellow"];
       $newArray_056 = array_keys($color_056); //with iA array
       echo '<pre>';
       print_r($newArray_056);
       echo '</pre>';
        
       $color_a_056 =[
                 "first" =>"red",
                 "second" =>"green",
                 "third" =>"blue",
                 "fourth" =>"yellow"
               ];
               
       $newArray_a_056 = array_keys($color_a_056); // With aA Array
       
       echo '<pre>';
       print_r($newArray_a_056);
       echo '</pre>';
        
       $newArray_b_056 = array_key_first($color_a_056); // return first key
       echo 'array_key_first <pre>';
       print_r($newArray_b_056);
       echo '</pre>';
               
       $newArray_c_056 = array_key_last($color_a_056); // return last key
       echo 'array_key_last<pre>';
       print_r($newArray_c_056);
       echo '</pre>';
       
       $newArray_d_056 = array_key_exists("third", $color_a_056); // check if exists
       echo 'array_key_exists<pre>';
       print_r($newArray_d_056);
       echo '</pre>';
       
       $newArray_e_056 =  array_key_exists("six", $color_a_056); // check if exists
       echo 'array_key_exists<pre>';
       print_r($newArray_e_056);
       echo '</pre>';
       
       $newArray_f_056 = key_exists("second", $color_a_056); // above short name 
       echo 'key_exists <pre>';
       print_r($newArray_f_056);
       echo '</pre>';
       
           /* using if else with above code */
       if ($newArray_f_056)
         {
           echo "Key exists!";
         }
         else
         {
           echo "Key does not exist!";
         }
         echo '</br>';    
?>