John Davidson

Message:

I have question
My code works but i dont understand what is $x[1] and $y[1] in function
I tryed $x[0], $x[1], $x[2], $y[0], $y[1], $y[2] and dont get the logical output ? Where i am wrong to understand ? Please if someone can help me ?

<?php

$products = array( array('TIR', 'Tires', 100),

                   array('OIL', 'Oil', 10),

                   array ('SPK', 'Spark Plugs', 4));



//print_r ($products); echo '<br />';

                 

function compare($x, $y) {

    if ($x[1] == $y[1]) {

        return 0;

    } else if ($x[1]<$y[1]) {

        return -1;

    } else {

        return 1;

    }

}



usort ($products, 'compare');



echo compare('Tires', 'Tires' );

echo compare('Oil', 'Spark Plugs' );

echo compare('Spark Plugs', 'Oil' );

echo compare('Tires', 'Tires');

echo '<br />';

Output is for this code for echo 1, 2, 3, 4:

0

-1

1

0

---

My Answer:
In the `compare` function, `$x[1]` and `$y[1]` are referring to the second element in the arrays `$x` and `$y` respectively. In this case, the second element in each sub-array of the `$products` array is the product name.

When you call the `compare` function with strings like 'Tires', 'Oil', etc., you are not passing arrays as arguments, so `$x[1]` and `$y[1]` are not valid. That's why you are not getting the expected output.

If you want to compare strings directly, you can modify the `compare` function to take strings as arguments like this:

php
function compare($x, $y) {
if ($x == $y) {
return 0;
} else if ($x < $y) {
return -1;
} else {
return 1;
}
}


Then you can call the function like this:

php
echo compare('Tires', 'Tires' );
echo compare('Oil', 'Spark Plugs' );
echo compare('Spark Plugs', 'Oil' );
echo compare('Tires', 'Tires');
echo '
';


This will give you the correct output for comparing strings directly.