| Problems with Variable Variables
need to use dynamic variables for a script |
cosmoyoda
msg:3625125 | 3:51 am on Apr 12, 2008 (gmt 0) |
Hello, Basically I have an array called sidebar_{name-of-the-section-goes-here}, which has a list of Items that need to be added to the sidebar navigation at the left of the page. So, I created a sidebar that will generate a UL list with all the LI elements according to which section of the site we're in. The URL parameter ?section=home, for instance, would tell the sidebar that it needs to have all items from the $sidebar_home array. Perfect! The problem I have is that I don't seem to be able to name dynamic variables properly. Here's a simpler version of my code: | <?php $sub_section = $_GET['section']; for ($i = 0; $i < 5; $i++) { $sidebar_var_name = "sidebar_" . $sub_section[$i]; echo $$sidebar_var_name . "<br />"; } ?> |
|
Ok, this is just a simpler version, with no UL or LI tags, but you get the idea. I don't know what's wrong with my syntax and why this isn't working. Any ideas? Thank you!
|
cosmoyoda
msg:3625126 | 3:58 am on Apr 12, 2008 (gmt 0) |
Also, this is the error I got in my page: Notice: Undefined variable: sidebar_w in "MY-ROOT-DIRECTORY-GOES-HERE" on line "LINE-NUMBER"
|
|
MY-ROOT-DIRECTORY-GOES-HERE and LINE-NUMBER are of course irrelevant here, but you get the idea. The variable is certainly not recognized by the PHP engine.
|
tutorial
msg:3625231 | 8:54 am on Apr 12, 2008 (gmt 0) |
Could you provide some more code, I don't find this very helpful.
|
coopster
msg:3625383 | 4:56 pm on Apr 12, 2008 (gmt 0) |
So what I see here then is that the value of $sub_section[$i] is the string "w" because when you concatenate it to the string "sidebar_" and try to use that variable variable it is saying it is undefined. Another way of writing your code would be ...
$sidebar_var_name = "sidebar_w";
And when you do this ...
echo $$sidebar_var_name . "<br />";
... it is the same as doing this:
echo $sidebar_w . "<br />";
So, is the $sidebar_w variable defined? Obviously not or you would not be getting that error message.
|
cosmoyoda
msg:3626018 | 10:28 pm on Apr 13, 2008 (gmt 0) |
Hello friends,
Turns out I found a solution last night. | <?php // If $my_section = "Home".
$my_section = "home"; for ($i = 0; $i < 10; $i++) { $my_sidebar_var = "sidebar_" . $my_section;
$sidebar_item = ${$my_sidebar_var}[$i]; echo "<li>" . $sidebar_item . "</li>" . "<br />";
} ?> |
|
So basically now the loop will call everytime the variable $sidebar_home[$1], which can be $sidebar_home[0], $sidebar_home[1], $sidebar_home[2], $sidebar_home[3] till... $sidebar_home[10]. Thanks for the help guys.
|
|
|
