var_dump

echo

• Outputs one or more strings separated by commas
• No return value
  e.g. echo "String 1", "String 2"

print

• Outputs only a single string
• Returns 1, so it can be used in an expression
  e.g. print "Hello"
  or, if ($expr && print "foo")

print_r()

• Outputs a human-readable representation of any one value
• Accepts not just strings but other types including arrays and objects, formatting them to be readable
• Useful when debugging
• May return its output as a return value (instead of echoing) if the second optional argument is given
• There are two more functions similar to print_r() which are var_export(), and var_dump(). They display the private and protected properties of objects.
• print_r (mixed $var_name, boolean $return_output)  

var_dump()

• Outputs a human-readable representation of one or more values separated by commas
• Accepts not just strings but other types including arrays and objects, formatting them to be readable
• Uses a different output format to print_r(), for example it also prints the type of values
• Useful when debugging
• No return value

var_export()

• Outputs a human-readable and PHP-executable representation of any one value
• Accepts not just strings but other types including arrays and objects, formatting them to be readable
• Uses a different output format to both print_r() and var_dump() - resulting output is valid PHP code!
• Useful when debugging
• May return its output as a return value (instead of echoing) if the second optional argument is given

var_dump

hat dumps the information about the variables.

<?php  

    //PHP program to demonstrate the working of var_dump function  

    $x = 25;  

    //dump integer variable  

    var_dump ($x);            

    echo "</br>";  

      

    $y = 32.5;  

    //dump float variable  

    var_dump ($y);            

    echo "</br>";  

      

    $bvalue = true;  

    //dump boolean variable  

    var_dump ($bvalue);  

?>  

int(25)
float(32.5)
bool(true)

<?php  

    //dump strings  

    $msg1 = "Hello Alex";  

    var_dump ($msg1);  

      

    echo "</br>";  

    $msg2 = "Welcome to javatpoint";  

    var_dump ($msg2);  

?>  

string(10) "Hello Alex"
string(21) "Welcome to javatpoint"