"Variable Variables, PHP, and You"

tewebe

Hi, 🙂

I have read the lesson "Variable Variables, PHP, and You" end i have a big question:
With the exemple, if
$x = "this";
$$x = "is cake";
we can see the value of $this
but how can we do, if the value of $x came from a datebase, to see the value of this new variable? :-?

Thanks for the answer and sorry for my english (i'm french)...

tewebe

Barthak

How about ${$x}???

tewebe

Originally posted by Barthak
How about ${$x}???

when i do this:

while ($row=mysql_fetch_array($result,MYSQL_ASSOC))
{
$x1 = "droits_" . $row["objet"] . "[1]";
.../...
}

with $row["objet"] value is "membre" for exemple, i want to use the value of the variable name $creation_membre[1], but using ${$x1} in an echo to see his value, show me this:

$x1=droits_membre[1] et ${$x1}=

$($x1) seem to be N/A...
i'll have alsa to note that the "creation_membre" array is the name of input field from a form:

tewebe

Originally posted by tewebe

when i do this:

while ($row=mysql_fetch_array($result,MYSQL_ASSOC))
{
$x1 = "droits_" . $row["objet"] . "[1]";
.../...
}

with $row["objet"] value is "membre" for exemple, i want to use the value of the variable name $creation_membre[1], but using ${$x1} in an echo to see his value, show me this:

$x1=droits_membre[1] et ${$x1}=

$($x1) seem to be N/A...
i'll have alsa to note that the "droits_membre" array is the name of input field from a form:

<input type=checkbox name=droits_membre[] checked>
<input type=checkbox name=droits_membre[] checked>
<input type=checkbox name=droits_membre[] checked
<input type=checkbox name=droits_membre[] checked>

Barthak

$x1 = "droits_" . $row["objet"] . "[1]";

this will merely make $x1 a string. Not a variable.
print( $x1 ); will parse: droits_membre[1].

you might wanna do it like this:

$x1 = ${droits_ . $row['objet']}[1];

Now you'll have a variable, variable array.?

tewebe

Originally posted by Barthak
$x1 = "droits_" . $row["objet"] . "[1]";

this will merely make $x1 a string. Not a variable.
print( $x1 ); will parse: droits_membre[1].

you might wanna do it like this:

$x1 = ${droits_ . $row['objet']}[1];

Now you'll have a variable, variable array.?

Thanks, I will try and say you if it is good or not... 🙂
It's difficult to me to explain in english but I'm happy to have find this forum 🙂

tewebe

It work Barthak, thanks so lot 🙂

troublemaker

Take a look at the code below. I run it on a PHP3 machine.

The table is a quick way to show what happens to the variables with the box checked & un-checked.

It works perfectly.

<?PHP
//$checked = "Yes";
$var1="Loser";
if ($$var1 == "Yes") {
$$var1 = "checked";
}
else {
$$var1 = "";
}

echo "
<html>
<head>
<title>Check</title>
<meta http-equiv=\"Content-Type\" content=\"text/html; charset=iso-8859-1\">
</head>

<body bgcolor=\"#FFFFFF\" text=\"#000000\">
<form method=\"post\" action=\"check.php\">
<table width=\"228\" border=\"1\" cellspacing=\"2\" cellpadding=\"2\">
<tr>
<td width=\"74\">Value-->></td>
<td width=\"40\">

    <div align=\"center\"> 
      <input type=\"checkbox\" name=\"$var1\" value = \"Yes\" ${$var1}>", $var1;
	  echo"
    </div>

</td>
	<td width=\"86\">$checked</td>
    <td width=\"86\">$$var1</td>
	<td width=\"86\">${$var1}</td>

</tr>
<tr>
<td colspan = \"3\" align = \"middle\">
<input type=\"submit\" value=\"Submit\"></td>
</tr>
</table>
</form>
</body>
</html> ";
?>

troublemaker

A follow-up to this post,

I noticed that I have stored several options in a table;

"blue", "light blue", "green",...

Where the use of the "variable variable" falls apart, is if I try to detect $$var1, where $$var1 contains "light blue"

if ($$var1 == "Yes") {
$$var1 = "checked";
}

If I echo $$var1, it shows up empty..

The SPACE between the characters is the problem......

Have not figured out a fix yet.

Does anyone have an idea?😕

Weedpacket

<?php
${'light blue'}='Yes';
$var1='light blue';
if ($$var1 == "Yes") {
$$var1 = "checked";
}
echo $var1.'<br>'.$$var1.'<br>'.${'light blue'};
?>

Or just use arrays.

PS: get_defined_vars() can also be pretty useful.

troublemaker

echo $var1.'<br>'.$$var1.'<br>'.${'light blue'};

This is an unknown variable "light blue". It is pulled out of a table at form display time, hence you cannot use your syntax.

it has to be..

echo $var1.'<br>'.$$var1.'<br>'.${'$var1'};

& as I said, the space in the phrase
"light blue" is causing the variable to be displayed as a blank....