CODEWITHSUNDEEP
php
Tamás Pap
Tamás Pap

Reputation: 18273

Functions and the OR operator

Is there in PHP a shorthand for:

function a() {...}
function b() {...}

$c = a();
$c = ($c) ? $c : b();

In javascript you can simply do:

$c = a() || b();

but in PHP, if you do this, $c will be a boolean (which is normal, but I want to know if there exists another shorthand which does what I want).

UPDATE
Thank you guys for all the answers.

The shortest way to do it seems to be:

$c = a() ?: b();

I personally also like:

$c = a() or $c = b();

for the good readability.

Upvotes: 0

Views: 88

Answers (7)

Sverri M. Olsen
Sverri M. Olsen

Reputation: 13273

It is not possible to do it like in Javascript, but you can use the short version of the ternary construct:

$c = a() ?: b();

Another way is to use or's lesser precedence. It is not as pretty, but it actually comes closer to how you can do it in Javascript:

$c = a() or $c = b();

Another way of representing the above, so that it is easier to understand, is to wrap it in parentheses:

($c = a()) or ($c = b());

The assignment operator, =, has greater precedence than the "or" operator (do not confuse it with the || operator, though), which means that the part after or will not be executed if the first part evaluates to true. It is essentially the same as this:

if ($c = a()) {
    // Do nothing
} elseif ($c = b()) {
    // Do nothing
}

Both expressions are assignments that evaluate to either true or false. If the first expression is true then $c will be a(). Otherwise the second expression will be be tried, and because it is the last expression, and because nothing is done after that, $c will just be equal to b().

In any case, this is not really an important problem. If you use time on worrying about the aesthetics of variable assignment then you are not worrying about the right things.

Upvotes: 2

Achrome
Achrome

Reputation: 7821

You can use the assignment operator to your benefit.

($c = a()) || ($c = b());
echo $c;

Here's a demo : http://codepad.org/kqnKv2y4

Upvotes: 1

Gumbo
Gumbo

Reputation: 655219

You can do this:

$c = a() OR $c = b();

Upvotes: 1

Smar
Smar

Reputation: 8591

There is possibility to use black magic like this. I’d prefer to write it in longer form though. 

function a() {
    return false;
}
function b() {
    return true;
}

($c = a()) || ($c = b());

echo $c;

Upvotes: 1

Halfstop
Halfstop

Reputation: 1772

I'm assuming that you are looking for this.

http://www.php.net/manual/en/language.operators.comparison.php#language.operators.comparison.ternary

$c = a() ? $c : b();

I'm not sure what you're going for though.

Upvotes: -1

jtavares
jtavares

Reputation: 449

I like it this way, but its a question of preference

if( !$c=a() ){
    $c=b();
}

as in

if(!$User=$db->getUserFromID($user_id)){
    $User=$db->getUserFromUsername($username);
}

Upvotes: 1

sybear
sybear

Reputation: 7784

This may work:

$c = ($c) ? : b();

Upvotes: 3

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