compact

(PHP 4, PHP 5, PHP 7)

compactCreate array containing variables and their values

Description

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().

Note:

Before PHP 7.3, any strings that are not set will silently be skipped.

Parameters

varname1

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.

Errors/Exceptions

compact() issues an E_NOTICE level error if a given string refers to an unset variable.

Changelog

Version Description
7.3.0 compact() now issues an E_NOTICE level error if a given string refers to an unset variable. Formerly, such strings have been silently skipped.

Examples

Example #1 compact() example

<?php
$city  
"San Francisco";
$state "CA";
$event "SIGGRAPH";

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

$result compact("event""nothing_here"$location_vars);
print_r($result);
?>

The above example will output:

Array
(
    [event] => SIGGRAPH
    [city] => San Francisco
    [state] => CA
)

Notes

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 3 notes

up
126
M Spreij
11 years ago
Can also handy for debugging, to quickly show a bunch of variables and their values:

<?php
print_r
(compact(explode(' ', 'count acw cols coldepth')));
?>

gives

Array
(
    [count] => 70
    [acw] => 9
    [cols] => 7
    [coldepth] => 10
)
up
33
Robc
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.
up
10
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.
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