Shortcut for falsy expression

[csdude55]

I have a common area where I'm looking at non-null (but empty) results from MySQL, and when that happens I need to fall back to a default.

This doesn't work, because it's not null:

$img ?= $imgTwo ? 'default.gif';

This does work, though:

$img = $img ?: $imgTwo ?: 'default.gif';

Is there a way to shorten that second one so that $img isn't listed twice? I know that this doesn't work, but something like it:

$img ?:= $imgTwo ?: 'default.gif';

[mack]

I might be misunderstanding, but what I tend to do is set a default value at the start of the script...
$thing="default";

Then as the script progresses I can check if it has been altered using an if clause...

if ($thing != "default")
{
//default value has been overwritten by the script. Get the value and do something with it. Else ignore it.
}

Mack.

[ronin]

In certain contexts, I do like super-concise operators like:

? : (ternary operator shorthand)

? ? (null coalescing operator)

? ? = (null coalescing assignment operator)

But you're right, there isn't a ternary operator shorthand assignment operator (?:=) and, I agree, that would be useful.

I don't know if it makes much of a difference, but you could use something like:

(boolval($img)) ?: $img = ($imgTwo ?: 'default.gif');

[csdude55]

Thanks for the input! I tried a few different versions, and it looks like ?? is the fastest:

// 2.2482872009277
if (!isset($img))
 $img = $imgTwo;

if (!isset($img))
 $img = 'default.gif';

// 2.6202201843262
//  I also get warnings if $img and $imgTwo aren't defined, but using ? throws an error so I'm
//  not sure what the best solution is there
(boolval($img)) ?: $img = ($imgTwo ?: 'default.gif');

// 1.5783309936523
$img = $img ? $imgTwo ? 'default.gif';

I usually try to avoid reading the same variable multiple times for the sake of speed, but I guess there's not an alternative in this case :-/