Convert Key => Value Arrays Into Standard Variables In PHP
I don't mind using arrays -- in fact, I love them. They're easy to use and hold collections of information well.
I don't always want to use arrays though. Why use:
echo $user['first_name'];
when you could simply use:
echo $first_name;
So how can we get rid of the array part of the variables?
The Code
foreach($user as $key=>$value) { $$key = $value; }
//or....
foreach($user as $key=>$value) { ${$key} = $value; }A few variables you must be careful with are:
- $_GET
- $_POST
- $_REQUEST
Why? Because $_GET, $_POST, and $_REQUEST variables can manipulated by the user and that would present a huge security concern.
Discussion
Be Heard!
Share your thoughts with fellow developers of all skill levels! I want to hear from you!
Interesting effect, but it has the same effect of php’s extract function! In your example, you can do extract($user); and so call $first_name; ;)
http://www.php.net/extract
Good point Hugo. My post wasn’t detailed enough, or perhaps was over-simplified.
With the loop, you can do special operations to the values. For example:
foreach($_POST as $key=>$value)
{
$key = stripslashes($value);
}
…removes slashes.
I have used this alot for both GET’s and POST’s, sure, they can create their own variables, who cares? If I use a variable, I always declare it after pulling from get or post, the variables that I use from post and get are also validated for correct values.
Also, something I have found handy for dealing with case sensitivity for get variables, (since sometimes if someone posts it to say, ICQ for someone else to visit, ICQ will lowercase the whole string) is
foreach($_GET as $k = $v) {
$k = strtolower($k);
\$$k = $v
}
then you can safely test to see if the get was set
if(isset($variablenametotestfor)) {//begin execution}
Also, per using the method for GET POST or REQUEST you could use a regex match on the $k to only convert expected variable names.
IE:
$acceptedGETS = /(varname1)|(varname2)|(varname3)|(etc)/
foreach($_GET as $key => $value) {
$key = strtolower($key);
if $key.match($acceptedGETS) $$key = $value;
}
This will prevent someone from creating their own variable names
Thank you for the RegEx, Peter — that could prove very useful!
Sorry, there was an error in my regex syntax there, I learned regex with javascript, and just learning PHP regEx… I got the two confused when I wrote that
The correct syntax for the above would be
$acceptedGETS = “/\bvarname1\b|\bvarname2\b|\bvarname3\b|\betc\b/”;
foreach($_GET as $key => $value) {
$key = strtolower($key);
if (preg_match($acceptedGETS,$key)) $$key = $value;
}
the \b is required on both sides of each variable name to force exact words, without them qvarname1x34r would match.
Hey is not on google so I was wondering what the ${ } does? I have never seen it before.
Hi David,
I think the brackets are just a way of delimiting the variable’s name from the rest of the string.
Say you had variable $table_prefix,
echo “table name: $table_prefix_users”; // would return “table name: “;
echo “table name: ${table_prefix}_users”; // would return “table name: wp_users”;
I am not sure about this :) I am most likely wrong.
Cheers!
Droope
No, Droope is correct. Mostly.
The ${ } does designate a string.
But the purpose of this article is showing how to easily assign array variables to their key name. I know that sounds confusing, but its it.
Example:
$people['me'] = ‘robert’;
$people['friend'] = ‘sam’;
$people['girl'] = ‘bailey’;
foreach($people as $key => $val) {
// ${“me”} = ‘robert’
${$key} = $val; //or $$key = $val;
}
So that
echo $me; //echo “robert”;
(great blog, btw)