Printing a PHP 2D Array

Question

I have the following code:

<!DOCTYPE html>
<html >
<head>
    <title>Distance</title>
</head>

<body>
    <?php

        $distance = array(
            array(0, 200, 57, 223),
            array(200, 0, 150, 5),
            array(57, 150, 0, 177),
            array(57, 150, 0, 177),
            array(223, 5, 177, 0)
        );

        $cityA = filter_input(INPUT_POST, "cityA");
        $cityB = filter_input(INPUT_POST, "cityB");
        $result = $distance[$cityA][$cityB];

        print "<p> The distance between the 2 cities is $result</p>";

    ?>
</body>
</html>

For the code:

 print "<p> The distance between the 2 cities is $result</p>";

The result is:

The distance between the 2 cities is 177

But if I change it to:

 print "<p> The distance between the 2 cities is $distance[$cityA][$cityB]</p>";

The result becomes:

The distance between the 2 cities is Array[0]

Could anyone explain why $distance[$cityA][$cityB] is not interpreted as an 2D array when I try to print it directly?

You need to change your $distance array to have both keys and values, because I don't see how your script knows which city has what coordinates. — David
– David, Commented Aug 14, 2012 at 14:34
@David: It does have keys, that how arrays work. They are numeric. From 0-4, and 0-3. — gen_Eric
– gen_Eric, Commented Aug 14, 2012 at 14:35

gen_Eric · Accepted Answer · 2012-08-14 14:35:15Z

4

Try to wrap it in curly braces.

print "<p> The distance between the 2 cities is {$distance[$cityA][$cityB]}</p>";

answered Aug 14, 2012 at 14:35

gen_Eric

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2 Comments

fall Over a year ago

Thanks for the solution, Rocket. But why is my approach not working? PHP should understand $var and should recognize it when I put it in a print statement.

gen_Eric Over a year ago

@fall: It seems PHP stops parsing at the 1st ], and the 2nd [$cityB] isn't read as part of the variable.

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