(PHP 4, PHP 5, PHP 7)

compactCreate array containing variables and their values


array compact ( mixed $varname1 [, mixed $... ] )

Creates an array containing variables and their values.

For each of these, compact() looks for a variable with that name in the current symbol table and adds it to the output array such that the variable name becomes the key and the contents of the variable become the value for that key. In short, it does the opposite of extract().

Any strings that are not set will simply be skipped.



compact() takes a variable number of parameters. Each parameter can be either a string containing the name of the variable, or an array of variable names. The array can contain other arrays of variable names inside it; compact() handles it recursively.

Return Values

Returns the output array with all the variables added to it.


Example #1 compact() example

"San Francisco";
$state "CA";
$event "SIGGRAPH";

$location_vars = array("city""state");

$result compact("event""nothing_here"$location_vars);

The above example will output:

    [event] => SIGGRAPH
    [city] => San Francisco
    [state] => CA


Note: Gotcha

Because variable variables may not be used with PHP's Superglobal arrays within functions, the Superglobal arrays may not be passed into compact().

See Also

  • extract() - Import variables into the current symbol table from an array

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User Contributed Notes 5 notes

tatarynowicz at gmail dot com
7 years ago
Please note that compact() will _not_ issue a warning if the specified variable name is undefined.
M Spreij
11 years ago
Can also handy for debugging, to quickly show a bunch of variables and their values:

(compact(explode(' ', 'count acw cols coldepth')));


    [count] => 70
    [acw] => 9
    [cols] => 7
    [coldepth] => 10
7 years ago
The description says that compact is the opposite of extract() but it is important to understand that it does not completely reverse extract().  In particluar compact() does not unset() the argument variables given to it (and that extract() may have created).  If you want the individual variables to be unset after they are combined into an array then you have to do that yourself.
jmarkmurph at yahoo dot com
2 years ago
So compact('var1', 'var2') is the same as saying array('var1' => $var1, 'var2' => $var2) as long as $var1 and $var2 are set.
piedone at pyrocenter dot hu
7 years ago
A quick way of compacting all local variables:

= compact(array_keys(get_defined_vars()));

This is useful if you want to return all local variables from a function/method or you want to pass all local variables to one. A valid example would be to use this with application hooks/events (if you want the called hook to be able to modify everything in the caller), but otherwise use with care (as methods should be used through their declared interface).
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