Here is the example code to practice some important PHP array functions that you can copy paste into the IDE of your choice to practice. The PRE tag is used to preformat the array output nicely so that it makes more sense visually.

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    <?php
        $fruits = ["Apple","Orange","Banana"];

        //print_r array
        echo '<pre>';
            echo '<h3>';
                echo 'print_r($array)';
            echo'</h3>';
            print_r($fruits);
        echo '</pre>';

        //var_dump array
        echo '<pre>';
            echo '<h3>';
                echo 'var_dump($array)';
             echo'</h3>';
             var_dump ($fruits);
        echo '</pre>';
//Add an element at the end of an array
        array_push($fruits,"Mango");
        echo '<pre>';
            echo '<h3>';
                echo 'array_push($array,$element); Adding an element at the end of Array';
            echo'</h3>';
            var_dump ($fruits);
        echo '</pre>';

        //Remove  an element at the end of an array
        array_pop($fruits);
        echo '<pre>';
            echo '<h3>';
                echo 'array_pop($array,$element); Removing an element from the end of Array';
            echo'</h3>';
            var_dump ($fruits);
        echo '</pre>';

        //array_unshift ($array,$element);Add an element to the start of an array
        array_unshift($fruits, "Mango");
        echo '<pre>';
            echo '<h3>';
                echo 'array_unshift ($array,$element); Add an element to the start of an array';
            echo'</h3>';
            var_dump ($fruits);
        echo '</pre>';

        //Remove an element from the start of an array
        array_shift($fruits);
        echo '<pre>';
            echo '<h3>';
                echo 'array_shift ($array,$element); Remove an element from the start of an array';
            echo'</h3>';
            var_dump ($fruits);
        echo '</pre>';

        //Check if a certain element is in an array, returns boolean true or false
        echo '<h3>';
                echo 'in_array ($element,$array); Returns boolean';
        echo'</h3>';
        echo in_array('Banana',$fruits); echo '</br>';

        //Check if a certain element is in an array, returns index of the element in an array
        echo '<h3>';
                echo 'array_search ($element,$array); Gives the position of element in an array';
        echo'</h3>';
        echo array_search('Banana',$fruits);

        //Merge two or more arrays into a single array
        $vegetables = ["Potatoes","Onions","Carrots"];
        $meat = ['Chicken','Fish'];
        echo '<h3>';
                echo 'array_merge ($array1,$array2); Merge two or more arrays into a single array';
        echo'</h3>';
        $fruitsVegetablesMeat = array_merge($fruits,$vegetables,$meat);
        echo '<pre>';
            print_r($fruitsVegetablesMeat);
        echo '</pre>';

        //Sort an Array; Changes the array permanently
        echo '<h3>';
                echo 'sort($array); sorts and changes array permanently';
        echo'</h3>';
        sort($fruits);
        echo '<pre>';
            print_r($fruits);
        echo '</pre>';

        //Filter an array based on criteria: In this example we pick even elements from an array
        echo '<h3>';
                echo 'filter_array($array); Filter an array based on criteria';
        echo'</h3>';
        $numbers = [1,2,3,4,5,6,7,8,9];

        //array_filter — Applies the callback to the elements of the given arrays
        //first argument array, second callback function

        function getEven($n){return $n%2==0;}
        function getOdd($n){return $n%2!=0;}
        $even = array_filter($numbers, "getEven");
        $odd = array_filter($numbers, "getOdd");
        echo '<pre>';
            print_r($even);
        echo '</pre>';
        echo '<pre>';
            print_r($odd);
        echo '</pre>';

        //array_map — Applies the callback to the elements of the given arrays, first argument 
        //is a callback function, second argument is an array
        //in case we apply array_map with the even odd callback functions, it returns true false 
        //instead of element for some reason
        //so used getSquare function instead of getEven and getOdd.
        echo '<h3>';
                echo 'array_map(callback,$array); 
                      Filter an array based on criteria: 
                      In this example we get square of elements from an array';
        echo'</h3>';
        function getSquare($n){return $n*$n;}
        $square = array_map("getSquare", $numbers);
        echo '<pre>';
            print_r($square);
        echo '</pre>';
        
        //array_chunk - Chunks an array into arrays with length elements
        //array_column — Return the values from a single column in the input array
        //array_combine — Creates an array by using one array for keys and another for its values
        //array_count_values — Counts all the values of an array
        //array_diff — Computes the difference of arrays
    
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