print_r and var_dump output array in PHP, print_rvar_dump_PHP tutorial

print_r and var_dump in PHP output arrays. print_rvar_dump

print_r() and var_dump() functions can print out the entire array content and structure.

print_r()

Use the print_r() function to print out the entire array content and structure, and display the keys and elements in a certain format. Note that the print_r() function is not just for printing, it is actually used to print easy-to-understand information about the variables.

Grammar:

bool print_r( mixed expression ) example:

<&#63;php
$arr_age = array(18, 20, 25);
print_r($arr_age);
&#63;>

Run this example output:

Array ( [0] => 18 [1] => 20 [2] => 25 ) View the web page source code of the output result, you can see a more readable format:

Array
(
  [0] => 18
  [1] => 20
  [2] => 25
) 
var_dump()

Same as the print_r() function, the var_dump() function can also be used to print the data and structure of the array. However, the var_dump() function is more powerful than print_r(). It can print multiple variables at the same time and give the type information of the variables.

Example:

<&#63;php
$arr_age = array(18, 20, 25);
var_dump($arr_age);
&#63;>

Output of running this example:

array(3) {
 [0]=>
 int(18)
 [1]=>
 int(20)
 [2]=>
 int(25)
}

The print_r() and var_dump() functions are generally used for debugging programs. In more cases, echo is used to output specific array unit values.

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