The php print_r() function allows us to get human-readable information about our php variables. We can print arrays and objects with print_r().
$num = 5;
$string = "This is a string";
$array = ["This","is","an","array"];
print_r($num);
print_r($string);
print_r($array);
//Output:
5
This is a string
Array
(
[0] => This
[1] => is
[2] => an
[3] => array
)
When working with variables in programming, the ability to be able to print them out in a human-readable way is very useful.
The php print_r() function allows us to print information about a variable in a human-readable way.
With print_r(), we can output all types of variables, including arrays and objects.
If a string, int, or float variable is passed to print_r(), the value will be printed. If an array is passed, the elements will be printed in a format that shows the keys and values.
Below is an example of using print_r() to output different types of variables.
class exampleClass {
public $id;
private $name;
static protected $multiplyNumbers;
static function multiplyNumbers($a,$b) {
return $a * $b;
}
}
$num = 5;
$string = "This is a string";
$array = ["This","is","an","array"];
print_r(new exampleClass);
print_r($num);
print_r($string);
print_r($array);
//Output:
exampleClass Object
(
[id] =>
[name:exampleClass:private] =>
)
5
This is a string
Array
(
[0] => This
[1] => is
[2] => an
[3] => array
)
Returning the Information from print_r() Instead of Printing it in php
By default, print_r() prints human-readable information.
We can capture that information in a new variable by passing a second parameter to print_r().
Below is an example in php of how to return the information produced by print_r() in a new variable.
$array = ["This","is","an","array"];
$new_var = print_r($array, true);
echo $new_var;
//Output:
Array
(
[0] => This
[1] => is
[2] => an
[3] => array
)
Printing Arrays with print_r() in php
We can print an array in php is with the print_r() function.
As we know, print_r() prints human-readable information about a variable.
So, if you have an array, you can pass it to print_r() and get a human-readable array which shows all of the array keys and array values.
Below is an example in php showing how to print an array with print_r().
$array = ["This","is","an","array"];
print_r($array);
//Output:
Array
(
[0] => This
[1] => is
[2] => an
[3] => array
)
Printing Objects with print_r() in php
print_r() lets us print objects in a human-readable way.
If you have an object, you can pass it to print_r() and get a listing the public and private variables in the object.
Below is an example in php showing how to print an object with print_r().
class exampleClass {
public $id;
private $name;
static protected $multiplyNumbers;
static function multiplyNumbers($a,$b) {
return $a * $b;
}
}
print_r(new exampleClass);
//Output:
exampleClass Object
(
[id] =>
[name:exampleClass:private] =>
)
Hopefully this article has been useful for you to learn about the print_r() function in php and how to print variables in a readable way in your php programs.