globals ?

[Yang Li Ke]

Hi anyone know why a user running PHP Version 4.3.4
on a windows system cant run a script having a simple
code like this:

if($myvar){
header("Locatio n: $redirecturl");
}

it gives some undefined var error

I need help!

Thank you
--
Yang

[Jon Kraft]

Re: globals ?

"Yang Li Ke" <yanglike@sympa tico.ca> wrote:
[color=blue]
> Hi anyone know why a user running PHP Version 4.3.4
> on a windows system cant run a script having a simple
> code like this:
>
> if($myvar){
> header("Locatio n: $redirecturl");
> }
>
> it gives some undefined var error[/color]


It doesn't return an error but a notice. Because $myvar is obviously not
defined.

if(isset($myvar )){

is the better solution, although if the original code always returned the
notice, I presume "your friend" makes the common mistake of not keeping up
to date with PHP development and still expects form fields becoming
$variables as if by magic.

http://uk.php.net/manual/en/ref.errorfunc.php

http://uk.php.net/manual/en/language.variables.predefined.php

HTH;
JOn

[Michael Meckelein]

Re: globals ?

"Yang Li Ke" wrote[color=blue]
> Hi anyone know why a user running PHP Version 4.3.4
> on a windows system cant run a script having a simple
> code like this:
>
> if($myvar){
> header("Locatio n: $redirecturl");
> }
>
> it gives some undefined var error[/color]

Maybe you are using register_global s Off? In which way get you the $myvar,
$redirecturl?

If from a form via post, use this:
$_POST['myvar'], ...

or via get request, use this:
$_GET['myvar'], ...

Since PHP 4.2.0 register_global s is by default off. This is nice, don't
change this!

For more information see the manual at www.php.net

Michael

[Dan Tripp]

Re: globals ?

Michael Meckelein wrote:
[color=blue]
> "Yang Li Ke" wrote
>[color=green]
>>Hi anyone know why a user running PHP Version 4.3.4
>>on a windows system cant run a script having a simple
>>code like this:
>>
>>if($myvar){
>> header("Locatio n: $redirecturl");
>>}
>>
>>it gives some undefined var error[/color]
>
>
> Maybe you are using register_global s Off? In which way get you the $myvar,
> $redirecturl?
>
> If from a form via post, use this:
> $_POST['myvar'], ...
>
> or via get request, use this:
> $_GET['myvar'], ...
>
> Since PHP 4.2.0 register_global s is by default off. This is nice, don't
> change this!
>
> For more information see the manual at www.php.net
>
> Michael
>[/color]

I generally use something like this:

if(ISSET($_POST['var'])){
$var = $_POST['var'];
} else {
$var = "";
}

This way, if I haven't sent the variable $var to the form, I don't get
an error.

It can also be smooshed to one line...

if(ISSET($_POST['var'])){ $var = $_POST['var']; } else { var = ""; }

Regards,

- Dan

http://www.dantripp.com/

[Pedro Graca]

Re: globals ?

Dan Tripp wrote:[color=blue]
> It can also be smooshed to one line...
>
> if(ISSET($_POST['var'])){ $var = $_POST['var']; } else { var = ""; }[/color]


or, if you prefer a little more cryptic code:

$var = @$_POST['var']?$_POST['var']:'';
--
--= my mail box only accepts =--
--= Content-Type: text/plain =--
--= Size below 10001 bytes =--

[Dan Tripp]

Re: globals ?

Pedro Graca wrote:[color=blue]
> Dan Tripp wrote:
>[color=green]
>>It can also be smooshed to one line...
>>
>>if(ISSET($_PO ST['var'])){ $var = $_POST['var']; } else { var = ""; }[/color]
>
>
>
> or, if you prefer a little more cryptic code:
>
> $var = @$_POST['var']?$_POST['var']:'';[/color]

ROCK!

Thank you Pedro, that will save me *A LOT* of typing! Woot!

- Dan

http://blog.dantripp.com/

[Dan Tripp]

Re: globals ?

Pedro Graca wrote:
[color=blue]
> Dan Tripp wrote:
>[color=green]
>>It can also be smooshed to one line...
>>
>>if(ISSET($_PO ST['var'])){ $var = $_POST['var']; } else { var = ""; }[/color]
>
>
>
> or, if you prefer a little more cryptic code:
>
> $var = @$_POST['var']?$_POST['var']:'';[/color]


"PHP offers an alternative syntax for some of its control structures;
namely, if, while, for, foreach, and switch. In each case, the basic
form of the alternate syntax is to change the opening brace to a colon
(:) and the closing brace to endif;, endwhile;, endfor;, endforeach;, or
endswitch;, respectively."

http://us2.php.net/manual/en/control-structures.alternative-syntax.php

.... and here's the specific part that I think is cool:

"The expression (expr1) ? (expr2) : (expr3) evaluates to expr2 if expr1
evaluates to TRUE, and expr3 if expr1 evaluates to FALSE."

http://us2.php.net/manual/en/language.operators.comparison.php

Thanks again! =)

- Dan

[Eric Bohlman]

Re: globals ?

Dan Tripp <thisIsNot@MyEM ailAddress.com> wrote in
news:f0%Rb.1908 5$Rz.13648@news svr25.news.prod igy.com:
[color=blue][color=green]
>> $var = @$_POST['var']?$_POST['var']:'';[/color]
>
> ROCK!
>
> Thank you Pedro, that will save me *A LOT* of typing! Woot![/color]

Even less typing: $var = $_POST['var'] or '';

[Pedro Graca]

Re: globals ?

Dan Tripp wrote:[color=blue]
> Pedro Graca wrote:[color=green]
>> $var = @$_POST['var']?$_POST['var']:'';[/color][/color]
[color=blue]
> ... and here's the specific part that I think is cool:
>
> "The expression (expr1) ? (expr2) : (expr3) evaluates to expr2 if expr1
> evaluates to TRUE, and expr3 if expr1 evaluates to FALSE."
> http://us2.php.net/manual/en/languag...comparison.php[/color]

Yep! The ternary expression is what I used, with the '@' error
supressing:

$_POST['var'] evaluates to true if it has something except '0'.
If it is empty it evaluates to false.

If it does not exist and error_reporting is set to display Notices,
without the '@' for error suppressing, php would show the notice about
"undefined index". The '@' suppresses the error and treats $_POST['var']
as if it was the null string.
--
--= my mail box only accepts =--
--= Content-Type: text/plain =--
--= Size below 10001 bytes =--

[Martin Lucas-Smith]

Re: globals ?



[color=blue][color=green][color=darkred]
> >> $var = @$_POST['var']?$_POST['var']:'';[/color][/color]
>
> Yep! The ternary expression is what I used, with the '@' error
> supressing:
>
> $_POST['var'] evaluates to true if it has something except '0'.
> If it is empty it evaluates to false.
>
> If it does not exist and error_reporting is set to display Notices,
> without the '@' for error suppressing, php would show the notice about
> "undefined index". The '@' suppresses the error and treats $_POST['var']
> as if it was the null string.[/color]

But it's still an error. Surely the most correct way to handle this, if
using the ternary operator, is using isSet to check whether it exists:

$var = (isSet ($_POST['var']) ? $_POST['var'] : '');



Martin

[Pedro Graca]

Re: globals ?

Martin Lucas-Smith wrote:[color=blue][color=green][color=darkred]
>> >> $var = @$_POST['var'] ? $_POST['var'] : '' ;[/color][/color]
> $var = (isSet ($_POST['var']) ? $_POST['var'] : '');[/color]

I agree the second form is better.
.... and (unexpectedely) it is faster! *much* faster!!

#v+
<?php
$start1 = microtime();
$n = 1000000; while (--$n) {
$var1 = @$_POST['var'] ? $_POST['var'] : '' ;
}
$end1 = microtime();

$start2 = microtime();
$n = 1000000; while (--$n) {
$var2 = (isSet ($_POST['var']) ? $_POST['var'] : '');
}
$end2 = microtime();

$delta1 = array_sum(explo de(' ', $end1)) - array_sum(explo de(' ', $start1));
$delta2 = array_sum(explo de(' ', $end2)) - array_sum(explo de(' ', $start2));

echo "delta1 = $delta1\ndelta2 = $delta2\n\n";
?>
#v-

Result on my computer:
delta1 = 20.6845738888
delta2 = 3.95724010468
--
--= my mail box only accepts =--
--= Content-Type: text/plain =--
--= Size below 10001 bytes =--

[Andy Hassall]

Re: globals ?

On Thu, 29 Jan 2004 12:00:31 +0000, Martin Lucas-Smith <mvl22@cam.ac.u k> wrote:
[color=blue][color=green][color=darkred]
>>>> $var = @$_POST['var']?$_POST['var']:'';[/color]
>>
>> Yep! The ternary expression is what I used, with the '@' error
>> supressing:
>>
>> $_POST['var'] evaluates to true if it has something except '0'.
>> If it is empty it evaluates to false.
>>
>> If it does not exist and error_reporting is set to display Notices,
>> without the '@' for error suppressing, php would show the notice about
>> "undefined index". The '@' suppresses the error and treats $_POST['var']
>> as if it was the null string.[/color]
>
>But it's still an error. Surely the most correct way to handle this, if
>using the ternary operator, is using isSet to check whether it exists:
>
>$var = (isSet ($_POST['var']) ? $_POST['var'] : '');[/color]

That's definitely the formally correct way of doing it, but I admit I've been
tending sometimes to use just:

$var = @$_POST['var'];

... on the grounds that the only thing that can go wrong there is that it's an
invalid index, and you get $var set to NULL. This also gives you a distinction
between 'var' not having been sent at all, or having been sent as an empty
string. But if you're just going to later do an 'if ($var) { something; }' then
it doesn't much matter that it's empty or NULL; they both convert to false.

But for the situations where you always want it as a string, the
isset-with-ternary statement above is definitely the way to go.

--
Andy Hassall <andy@andyh.co. uk> / Space: disk usage analysis tool
<http://www.andyh.co.uk > / <http://www.andyhsoftwa re.co.uk/space>

[Andy Hassall]

Re: globals ?

On 29 Jan 2004 08:43:08 GMT, Eric Bohlman <ebohlman@earth link.net> wrote:
[color=blue]
>Dan Tripp <thisIsNot@MyEM ailAddress.com> wrote in
>news:f0%Rb.190 85$Rz.13648@new ssvr25.news.pro digy.com:
>[color=green][color=darkred]
>>> $var = @$_POST['var']?$_POST['var']:'';[/color]
>>
>> ROCK!
>>
>> Thank you Pedro, that will save me *A LOT* of typing! Woot![/color]
>
>Even less typing: $var = $_POST['var'] or '';[/color]

Doesn't avoid the warning, though, since you're using an undefined index.

--
Andy Hassall <andy@andyh.co. uk> / Space: disk usage analysis tool
<http://www.andyh.co.uk > / <http://www.andyhsoftwa re.co.uk/space>