PHP Manual: Create array containing variables and their values

Description

array compact(arraystring $var_name, arraystring ...$var_names)

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

var_name
var_names: 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_WARNING level error if a given string refers to an unset variable.

Changelog

Version	Description
8.0.0	If a given string references an unset variable, an `E_WARNING` level error is now issued.
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", $location_vars);
print_r($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.

compact