Ternary Operator - This is wrong right?

[SharkBait]

 

I can't do this can I?

 

<?php

$value = !empty($_POST['value']) ? $_POST['value'] : $message .= "You forgot something";

?>

 

 

[Fergusfer]

I can't do this can I?

 

<?php

$value = !empty($_POST['value']) ? $_POST['value'] : $message .= "You forgot something";

?>

 

You sure can.  If $_POST['value'] is empty, both $message and $value will equal "You forgot something", though.

[kenrbnsn]

Instead of asking here, try it. I tried it and it assigned the value "You forgot something" to both $value and $message;

 

Ken

[SharkBait]

I did but i guess i should of shown what I was doing that was erroring on me:

 

<?php
$_SESSION['rmbrNotes'] = isset($_POST['chkNotes']) : $notes ? unset($_SESSION['rmbrNotes']);
?>

 

I get this error: Parse error: parse error, unexpected T_UNSET in /home/tingram/public_html/testsite/test.php on line 236

 

So i thought it it was I couldn't run functions after it, so I posted a more simpler version of what I wanted to do

[SharkBait]

But I guess its erroring because like you mention how it sets the first variable to whatever is being assessed?

 

so $_SESSION['rmbrNotes'] Cannot Be set to unset() right?

 

 

[SharkBait]

Ah solved it by making a function that returns a value ie:

 

<?php

function ClearSession($value) {
  if(isset($_SESSION[$value])) unset($_SESSION[$value])

  return 0;
}

$_SESSION['rmbrNotes'] = isset($_POST['chkNotes']) ? $notes : ClearSession("rmbrNotes");

?>

 

Though as I am looking at the above code.. it still isn't quite right is it? If I return 0 will it not set the $_SESSION variable??

 

[Fergusfer]

The ternary operator will set the value of the first variable to the result of either the first statement or the second statement depending on whether the condition evaluates true.  It makes sense to use the ternary operator where you wish to assign one value or another depending on the condition.  If you only want to make an assignment in one case or the other, it doesn't make sense.  I would re-write your example as so:

 

<?php

if (isset($_POST['chkNotes'])) {
  $_SESSION['rmbrNotes'] = $notes;
} elseif (isset($_SESSION['rmbrNotes']) {
  unset($_SESSION['rmbrNotes']);
}

?>

[btherl]

The reason for the error is that unset is not a function, it's a php construct.  It can't be used in some contexts (like inside a ternary operator).

[SharkBait]

Thanks for the answers and explanations

[nolochemical]

Greetings,

 

I was trying to minimize/optimize a few blocks of code when I arrived at this error. I have tried to find documentation about the prototype for ternary operators, but was unsuccessful.

Any ideas or hints as to why this returns an error or were I can find more documentation about ternary operator usage limits. Thanks in advanced. In the meanwhile I am going to continue my search.

 

Reproduce Code:

----------------------------------------------------------------------------

function foo($name){

 

($name == "") ? return 0 : echo $name."<br>" ;

 

}

----------------------------------------------------------------------------

Expected Result:

----------------------------------------------------------------------------

exit the current function

----------------------------------------------------------------------------

[aschk]

Again you're using a construct (echo), and you're not applying the ternary operator to a value. You're using it like it's an if statement.

What makes you think ternary operators are "more optimised" over if statements?

[nolochemical]

I understand your point, I have never tried to use ternary operators in this way before and when you mentioned "you're not applying the ternary operator to a value" is when I realized or remember why. Thanks for the second pair of eyes.

 

I am currently using if statements, there is nothing wrong with them. "I was trying to minimize/optimize a few blocks of code...". I find using a "minimal" amount of code is good way to "optimize" my applications.

 

thanks again,

 

~nolo

[btherl]

If by "optimize" you mean fewer lines of code or neater appearance, then that may be true, depending on your point of view.  You can also write an "if" in one line, though I don't think it looks as nice as the ternary operator.

 

I would not expect it to be any faster to execute.