What is the difference between echo, print,var_dump, and print_r in PHP?

print

 and 

echo

 are more or less the same; they are both language constructs that display strings. The differences are subtle: 

print

 has a return value of 1 so it can be used in expressions whereas 

echo

 has a 

void

 return type; 

echo

 can take multiple parameters, although such usage is rare; echo is slightly faster than print_r. (Personally, I always use, never 

print

.)

var_dump

 prints out a detailed dump of a variable, including its type and the type of any sub-items (if it’s an array or an object). 

print_r

 prints a variable in a more human-readable form: strings are not quoted, type information is omitted, array sizes aren’t given, etc.

var_dump

 is usually more useful than 

print_r

 when debugging, in my experience. It’s particularly useful when you don’t know exactly what values/types you have in your variables. Consider this test program:

$values = array(0, 0.0, false, '');

var_dump($values);
print_r ($values);

With 

print_r

 you can’t tell the difference between 

0

 and 

0.0

, or 

false

 and 

''

:

array(4) {
  [0]=>
  int(0)
  [1]=>
  float(0)
  [2]=>
  bool(false)
  [3]=>
  string(0) ""
}

Array
(
    [0] => 0
    [1] => 0
    [2] => 
    [3] => 
)