PHP | print_r() Function

Last Updated : 26 Apr, 2018

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.

$variable: This parameter specifies the variable to be printed and is a mandatory parameter.
$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 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 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

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