PHP | print_r() Function

The print_r() function is a built-in function in PHP and is used to print or display information stored in a variable. Syntax:

print_r( $variable, $isStore )

Parameters: This function accepts two parameters as shown in above syntax and described below.

1. $variable: This parameter specifies the variable to be printed and is a mandatory parameter.
2. $isStore: This an option parameter. This parameter is of boolean type whose default value is FALSE and is used to store the output of the print_r() function in a variable rather than printing it. If this parameter is set to TRUE then the print_r() function will return the output which it is supposed to print.

Return Value: If the $variable is an integer or a float or a string the function prints the value of the variable. If the variable is an array the function prints the array in a format which displays the keys as well as values, a similar notation is used for objects. If the parameter $isStore is set to TRUE then the print_r() function will return a string containing the information which it is supposed to print. Below programs illustrate the print_r() function: Program 1: PHP

<?php // PHP program to illustrate // the print_r() function // string variable $var1 = "Welcome to GeeksforGeeks"; // integer variable $var2 = 101; // array variable $arr = array('0' => "Welcome", '1' => "to", '2' => "GeeksforGeeks"); // printing the variables print_r($var1); echo"\n"; print_r($var2); echo"\n"; print_r($arr); ?> 

Output:

 Welcome to GeeksforGeeks 101 Array ( [0] => Welcome [1] => to [2] => GeeksforGeeks ) 

Program 2: PHP

<?php // PHP program to illustrate the print_r() // function when $isStore is set to true // array variable $arr = array('0' => "Welcome", '1' => "to", '2' => "GeeksforGeeks"); // storing output of print_r() function // in another variable $results = print_r($arr, true); echo $results; ?> 

Output:

 Array ( [0] => Welcome [1] => to [2] => GeeksforGeeks ) 

Reference: http://php.net/manual/en/function.print-r.php