print_r()
print_r() — Prints human-readable information about a variable.
Built-in function of PHP 8.5. The manual lists it as available in PHP 4, PHP 5, PHP 7, PHP 8. This page is the reference card: signature, parameters and return value, plus the changelog and the example the manual provides.
What it does
print_r() displays information about a variable in a way that's readable by humans.
Signature
print_r(mixed $value, bool $return = false): string|true
Parameters
| Parameter | Type | What it takes |
|---|---|---|
| $value | mixed | The expression to be printed. |
| $return | bool | If you would like to capture the output of print_r(), use the return parameter. When this parameter is set to true, print_r() will return the information rather than print it. |
Return value
If given a string, int or float, the value itself will be printed. If given an array, values will be presented in a format that shows keys and elements. Similar notation is used for objects. When the return parameter is true, this function will return a string. Otherwise, the return value is true.
Example
A runnable snippet:
<pre> <?php $a = array ('a' => 'apple', 'b' => 'banana', 'c' => array ('x', 'y', 'z')); print_r($a); ?> </pre>
Output:
<pre> Array ( [a] => apple [b] => banana [c] => Array ( [0] => x [1] => y [2] => z ) ) </pre>
Changelog
| Version | Change |
|---|---|
| 8.4.0 | Return type changed from string|bool to string|true. |
See also
ob_start(), var_dump(), var_export()
All PHP 8.5 built-in functions
Reference card built from the PHP manual page print_r() (PHP documentation, CC BY 3.0). The page is generated from the manual, so the wording of the parameter and return value text follows php.net.