How do I interpret some things in this function

PHP
1

I don’t understand what the question mark does in this function:

function makecoffee($types = array("cappuccino"), $coffeeMaker = NULL)
{
    $device = is_null($coffeeMaker) ? "hands" : $coffeeMaker;
    return "Making a cup of ".join(", ", $types)." with $device.\n";
}
echo makecoffee();
echo makecoffee(array("cappuccino", "lavazza"), "teapot");
2

It’s a ternary operator ( a lot of programming languages have one ) and it’s basically a short version of an if-then-else statement.

if ( is_null($coffeeMaker) ) {
  $device = "hands";
} else {
  $device = $coffeemaker;
}

is the statement as an if statement.

1 Like
3

[off-topic]
I can’t remember seeing join(…) used before.

The alias is so much more intuitive and readable than implode(…); which I always have to lookup for the needle and haystack.

Many thanks :slight_smile:
[/off-topic]

4

And what about the → in this:


<?php
function total_intervals($unit, DateInterval ...$intervals) {
    $time = 0;
    foreach ($intervals as $interval) {
        $time += $interval->$unit;
    }
    return $time;
}

$a = new DateInterval('P1D');
$b = new DateInterval('P2D');
echo total_intervals('d', $a, $b).' days';

// This will fail, since null isn't a DateInterval object.
echo total_intervals('d', null);
?>
5

It’s called a T_OBJECT_OPERATOR. You can find more on them on the PHP Manual page about Parser Tokens

You might find this page on StackOverflow useful too → http://stackoverflow.com/questions/2987963/what-does-do-or-mean-in-php

6

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