isset/unset

Hello :),

Can anyone please explain the isset and unset functions in php in relation to javascript (this will make it easier)

I have a script.

PHP Code:

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<?php
$var = "some string"
if(isset($var)) { //Returns true, the variable is set.
  unset($var); // undoes the variable
  echo $var; //echoes nothing.
}
?>

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Thanks for that simple example !

Is there anything else to isset function apart from checking if things are set ?

I dont think so.

Well thanks for your help :)

It can check if a given item exists in an array, too.

What do you mean ? do you mean something like isset(sesion_start()) ?

No he means:

PHP Code:

---

<?php
$arr = array(
"key"=>"val",
"num"=>"1234",
"letter"=>"abc",
"nonalphnum"=>"!@#$"
);
if(isset($arr["num"])){
  echo "The value is set"; //echos if it is set
  echo $arr["key"]; //echos "val" 
  unset($arr["key"]);
  echo $arr["key"]; //echos nothing, because it doesnt exist.
}
?>

---

OK thanks i see :)

Quote:

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PHP Code:

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  echo $arr["key"]; //echos nothing, because it doesnt exist. 


---

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Also throws a warning.

Thanks :), i understand the non-existing part but don't understand that thing about warning part...

And one more thing :), how do you record a persons ip address (PHP)

Quote:

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i understand the non-existing part but don't understand that thing about warning part...

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There are three levels of message in PHP: error, warning, and informational. By default, PHP only displays error messages, which indicate when something's gone wrong and the script is unable to continue. However, it can also display warning messages, which highlight bad coding practices (such as accessing non-existent variables or array elements) and other potential problems, and informational messages, which just give a information about what something is doing. To show them all (and I recommend doing this when debugging a script), call:

Code:

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error_reporting(E_ALL);

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Quote:

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how do you record a persons ip address

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The IP address of the client (note that this may also be a proxy) is stored in $_SERVER['HTTP_REMOTE_ADDR'].

Thanks for your posts guys :), just one question to twey - HOW DO YOU KNOW EVRYTHING ?!! :)

I don't... you evidently weren't here to see mwinter in action :)

Speaking of mwinter... were has he gone?

he hasnt posted scince the holidays...

So are you lot saying that mwinter was the best ?

One more question - is there a "dictionary" for php that lists all those functions ? eg HTTP_REMOTE_ADDR,....

Quote:

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Speaking of mwinter... were has he gone?

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We're not sure... djr33 emailed him, but there was no response.

Quote:

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is there a "dictionary" for php that lists all those functions ? eg HTTP_REMOTE_ADDR,....

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They're not functions, but yes: http://www.php.net/manual/en/reserve...riables.server.

www.PHP.net

//Oops... Posted at same time, Twey.