[SOLVED] explain "return == ? : ;" please

[Ryokotsusai]

I have an old somewhat broken script that I am trying to get working again, and there is a weird statement that comes up quite a bit

$something['this'] == 'abc' ? 'def' : 'ghi';

 

I can't for the life of me figure out what it is trying to do 

 

any help would be greatly appreciated 

 

[nathanmaxsonadil]

<?php

$first ? $second : $third

?>

 

If the value of the first subexpression is TRUE (non-zero), then the second subexpression is evaluated, and that is the result of the conditional expression. Otherwise, the third subexpression is evaluated, and that is the value.

from http://us.php.net/manual/en/language.expressions.php

[Ryokotsusai]

wow, there is a lot out there, i thought ==, != and all those were only for use in an if/while/etc

 

there is a lot of stuff i still need to learn 

 

EDIT>>

 

actually that has confused me too, so forgive for being a little slow with this, but what exactly is this evaluating for the second statement:

return $settings['ses_type'] == 'adv' ? 'ses' : 'tname'

[trq]

The == (comparison operator) won't work in the snippet you provided. It needs to be = (assignment operator).

[nathanmaxsonadil]

actually that has confused me too, so forgive for being a little slow with this, but what exactly is this evaluating for the second statement:

return $settings['ses_type'] == 'adv' ? 'ses' : 'tname'

What I understand is '1st' ? '2nd' : '3rd'

[Ryokotsusai]

i guess my question about that more specifically is what is it 'evaluating' when it hits

 'ses' 

?

 

is it just reading it, or is it doing something there

[trq]

If...

 

return $settings['ses_type'] == 'adv' ? 'ses' : 'tname';

 

is the actual code, it is exactly the same as...

 

<?php

 if ($settings['ses_type'] == 'ses') {
   return true;
 } else {
   return false;
 }

?>

 

To be honest though... that snippet makes little sense. maybe this is part of the reason your somewhat broken script is somewhat broken.

 

This part...

 

'adv' ? 'ses' : 'tname';

 

Is a ternary operator that checks if the first expression is true, if so it returns the second expression, else it returns the third. The expression 'adv' will always be true, so this ternary operator will always return 'ses'. having te first expression hard coded like that simply makes no sense.

[Ryokotsusai]

Thank you, I was able to get it working by commenting that out and having it return what i wanted it to, it is only a temporary fix until i figure out what was being attempted there though...

[akitchin]

just to correct thorpe a little, the equivalent of this:

 

return $settings['ses_type'] == 'adv' ? 'ses' : 'tname';

 

is this:

 

if ($settings['ses_type'] == 'adv')
{
  return 'ses';
}
else
{
  return 'tname';
}

 

it uses the portion before the question mark as the condition, returning (since the line begins with the return command) 'ses' if true, 'tname' if false.

[trq]

I guess I misread the code. I would write that...

 

return ($settings['ses_type'] == 'adv') ? 'ses' : 'tname';

 

but your right akitchen.

 

Ignore my posts all together, I just read the code wrong.

[akitchin]

i know, it drives me insane when people don't place their conditions within parentheses.

[Ryokotsusai]

if it returns, tname, there is nothing that can use that in the situation it comes up in, so i have no idea what was going on anyway

+

if it returns ses it needs tname  ??? so i got nothing on this

 

but now at least i understand what is going on when i see == ? : ; come up again

[teng84]

maybe

 

$teng = ($ok=='no')?'cool':'no';

 

echo $teng;

 

//give you something like cool

//is that what you mean

[trq]

but now at least i understand what is going on when i see == ? : ; come up again

 

I dont think you do as its not == ? : ; but <expression> ? <expression> : <expression>;

 

See the manual entry here.

[dbo]

Personally I suggest against writing code that looks like that. It can save you a few lines of code but the meaning as to what you're trying to accomplish is much more clear the other way... and as you're finding out when you go back to a script it's hard to figure out what you were doing months ago when you last worked on it. I typically try to always stay on the side of readability.

[Ryokotsusai]

as its not == ? : ; but <expression> ? <expression> : <expression>;

 

i know, but i am a tad lazy and typing the whole thing out goes against laziness 

[trq]

My point is, the == (comparison operator) has nothing at all to do with the ternary operator.

[Ryokotsusai]

your right, i didn't  :'(

 

u could have

$this ? if($me == $notme) {something} : $that;

?

 

and how does it evaluate something like 'ses'