(PHP 4 )
Prints human-readable information about a variable
( mixed expression)
print_r() displays information about a variable
in a way that's readable by humans. If given a string,
integer or float, the value itself will be
printed. If given an array,
values will be presented in a format that shows keys and
elements. Similar notation is used for objects.
Remember that print_r() will move the array
pointer to the end. Use reset() to bring
it back to beginning.
Tip: As with anything that outputs
its result directly to the browser, you can use the output-control functions to capture
the output of this function, and save it in a
string (for example).
$a = array ('a' => 'apple', 'b' => 'banana', 'c' => array ('x','y','z'));
Which will output:
[a] => apple
[b] => banana
[c] => Array
 => x
 => y
 => z
Prior to PHP 4.0.4, print_r() will continue forever
if given an array or object that
contains a direct or indirect reference to itself. An example
is print_r($GLOBALS) because
$GLOBALS is itself a global variable that
contains a reference to itself.
See also ob_start(), var_dump(),