basic if/else problem

[dirntknow]

As a noob i'm sure there's good reason why this doesn't work but what i'd like to achieve is when a visitor opens a page it displays 'no organisation selected' and when they select one from a list (that coding works fine so i've left it out!) it puts ?orgname etc into the url...hope that makes sense!

....but this particular bit doesn't work!! Any suggestions most welcome, thanks!

 

<?php

if ($_GET['orgname']='') {

echo "no organisaton selected";

}

else {

echo $_GET['orgname'];

}

?>

[Lamez]

<?php
if(empty($_GET['orgname']) || !isset($_GET['orgname']))
  echo "Nothing Selected";
else
  echo $_GET['orgname'];
?>

[Ken2k7]

I would put isset before empty.

[Lamez]

I don't think it matters since it is evaluated as a whole to single boolean.

[Ken2k7]

If something satisfies empty, it'll almost always satisfy isset making the latter almost useless. The only time that's not the case is if the value is null.

[Lamez]

As that may be true, it still does not matter what order they are in. The expression is evaluated as a whole.

 

 

true || false = true

false || false = false

false || true = true

true || true = true

 

I don't see why the order they are called matters.

 

[Ken2k7]

Internally, I'm not sure if it evaluates the entire expression if it's an OR statement. If the first statement evaluates to true, just return true. Why would you bother evaluating the rest?

 

true || anything || anything || ...  = true

[Lamez]

I would think the compiler would have to, it has to have someway of detecting first, what kind of expression it is. Only seems logical at that point to evaluate it as a whole.

[Ken2k7]

Detecting is easy. Just a regular expression. Evaluating is different.

[Lamez]

Detecting is easy. Just a regular expression. Evaluating is different.

 

I could not agree more, I am curious now. I am now going to have to find out.

[dirntknow]

Lol, thanks for the swift response guys! Tried it, it works so i'll work out how and why it works so I know for next time!! 

[Ken2k7]

To explain why it doesn't work, it's because of this line:

 

if ($_GET['orgname']='') {

When comparing two values, you require at least 2 = signs. The statement you have above is ALWAYS true, because you're setting the value of $_GET['orgname'] to the empty string and that is always true. So there is really no comparison to be done.

[dirntknow]

Haha, i'm sure I tried == at some point (along side many other little changes!) but probably had something else amiss as well! Thanks!!