What is PHP print_r() Function?
If you want to display information of a variable that human can read easily, then use print_r() function. It is useful for inspecting structure and values of arrays and objects.
Syntax:
print_r(variable, return)
Parameters:
The Function has 1 required parameter and 1 optional parameter-
variable (Required): It specifies a variable whose information we want to display.
return (Optional): It specifies whether the function should return the output instead of displaying or not. It can take 2 values-
- TRUE – If it is TRUE, the function return the output.
- FALSE – If it is FALSE, the function doesn’t return the output, instead, it displays it. It is the default value.
Return Values:
- When the second parameter “return” is FALSE, the function returns 1.
- When the second parameter “return” is TRUE, the function returns the output.
Examples:
Example 1:
<pre>
<?php
$languages = array("Markup" => "HTML", "Styling" => "CSS", "Scripting" => "Javascript", "Serverside" => "PHP");
$return_val = print_r($languages);
?>
</pre>
Output:
Array
(
[Markup] => HTML
[Styling] => CSS
[Scripting] => Javascript
[Serverside] => PHP
)
Example 2:
<pre>
<?php
$languages = array("Markup" => "HTML", "Styling" => "CSS", "Scripting" => "Javascript", "Serverside" => "PHP");
$output = print_r($languages, true);
echo "The stored value is- \n" . $output;
?>
</pre>
Output:
The stored value is-
Array
(
[Markup] => HTML
[Styling] => CSS
[Scripting] => Javascript
[Serverside] => PHP
)
Practical Usages of print_r() Function:
- It is used in debugging to understand the structure and values of complex data types like arrays and objects.
- It can display private and protected properties of an object which is helpful for debugging class instances. And, it ignores static class members.
Alternative to print_r() Function:
var_dump() is an alternative function to the print_r() function. var_dump() function also displays data types and length of the variable.
Notes:
Not to mention that the function can also a string, integer, or float type variable.
PHP Version Support:
PHP 4, PHP 5, PHP 7, PHP 8
Summary: PHP print_r() Function
print_r() is a built-in variable handling function. Use this function when you need to see a cleaner output of a complex data type in human readable format.