(PHP 4, PHP 5, PHP 7)
print_r — Prints human-readable information about a variable
print_r() displays information about a variable in a way that's readable by humans.
print_r(), var_dump() and var_export() will also show protected and private properties of objects with PHP 5. Static class members will not be shown.
expressionThe expression to be printed.
return
If you would like to capture the output of print_r(),
use the return parameter. When this parameter is set
to TRUE, print_r() will return the information rather than print it.
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.
When the return parameter is TRUE, this function
will return a string. Otherwise, the return value is TRUE.
Note:
When the
returnparameter is used, this function uses internal output buffering so it cannot be used inside an ob_start() callback function.
Example #1 print_r() example
<pre>
<?php
$a = array ('a' => 'apple', 'b' => 'banana', 'c' => array ('x', 'y', 'z'));
print_r ($a);
?>
</pre>
The above example will output:
<pre>
Array
(
[a] => apple
[b] => banana
[c] => Array
(
[0] => x
[1] => y
[2] => z
)
)
</pre>
Example #2 return parameter example
<?php
$b = array ('m' => 'monkey', 'foo' => 'bar', 'x' => array ('x', 'y', 'z'));
$results = print_r($b, true); // $results now contains output from print_r
?>
I add this function to the global scope on just about every project I do, it makes reading the output of print_r() in a browser infinitely easier.
<?php
function print_r2($val){
echo '<pre>';
print_r($val);
echo '</pre>';
}
?>
It also makes sense in some cases to add an if statement to only display the output in certain scenarios, such as:
if(debug==true)
if($_SERVER['REMOTE_ADDR'] == '127.0.0.1')
Here is another version that parses the print_r() output. I tried the one posted, but I had difficulties with it. I believe it has a problem with nested arrays. This handles nested arrays without issue as far as I can tell.
<?php
function print_r_reverse($in) {
$lines = explode("\n", trim($in));
if (trim($lines[0]) != 'Array') {
// bottomed out to something that isn't an array
return $in;
} else {
// this is an array, lets parse it
if (preg_match("/(\s{5,})\(/", $lines[1], $match)) {
// this is a tested array/recursive call to this function
// take a set of spaces off the beginning
$spaces = $match[1];
$spaces_length = strlen($spaces);
$lines_total = count($lines);
for ($i = 0; $i < $lines_total; $i++) {
if (substr($lines[$i], 0, $spaces_length) == $spaces) {
$lines[$i] = substr($lines[$i], $spaces_length);
}
}
}
array_shift($lines); // Array
array_shift($lines); // (
array_pop($lines); // )
$in = implode("\n", $lines);
// make sure we only match stuff with 4 preceding spaces (stuff for this array and not a nested one)
preg_match_all("/^\s{4}\[(.+?)\] \=\> /m", $in, $matches, PREG_OFFSET_CAPTURE | PREG_SET_ORDER);
$pos = array();
$previous_key = '';
$in_length = strlen($in);
// store the following in $pos:
// array with key = key of the parsed array's item
// value = array(start position in $in, $end position in $in)
foreach ($matches as $match) {
$key = $match[1][0];
$start = $match[0][1] + strlen($match[0][0]);
$pos[$key] = array($start, $in_length);
if ($previous_key != '') $pos[$previous_key][1] = $match[0][1] - 1;
$previous_key = $key;
}
$ret = array();
foreach ($pos as $key => $where) {
// recursively see if the parsed out value is an array too
$ret[$key] = print_r_reverse(substr($in, $where[0], $where[1] - $where[0]));
}
return $ret;
}
}
?>
Here is a function that formats the output of print_r as a expandable/collapsable tree list using HTML and JavaScript.
<?php
function print_r_tree($data)
{
// capture the output of print_r
$out = print_r($data, true);
// replace something like '[element] => <newline> (' with <a href="javascript:toggleDisplay('...');">...</a><div id="..." style="display: none;">
$out = preg_replace('/([ \t]*)(\[[^\]]+\][ \t]*\=\>[ \t]*[a-z0-9 \t_]+)\n[ \t]*\(/iUe',"'\\1<a href=\"javascript:toggleDisplay(\''.(\$id = substr(md5(rand().'\\0'), 0, 7)).'\');\">\\2</a><div id=\"'.\$id.'\" style=\"display: none;\">'", $out);
// replace ')' on its own on a new line (surrounded by whitespace is ok) with '</div>
$out = preg_replace('/^\s*\)\s*$/m', '</div>', $out);
// print the javascript function toggleDisplay() and then the transformed output
echo '<script language="Javascript">function toggleDisplay(id) { document.getElementById(id).style.display = (document.getElementById(id).style.display == "block") ? "none" : "block"; }</script>'."\n$out";
}
?>
Pass it a multidimensional array or object and each sub-array/object will be hidden and replaced by a html link that will toggle its display on and off.
Its quick and dirty, but great for debugging the contents of large arrays and objects.
Note: You'll want to surround the output with <pre></pre>
Sometimes print_r produces large output, especially when the data hierarchy is too deep. It is very difficult to analyze the dump about 1Mb length.
It would be great to have some way to fold arrays and objects and to look deeper into hierarchy only on demand.
Here is the solution. Just pass the print_r output to debug_var function:
debug_var('title', print_r($var, true));
and it will produce nice html with folding option.
<?php
ob_start();
?>
Locals: Array
(
[arr] => Array
(
[0] => Bon Object
(
[n] => id
[v] => 1
[dv] =>
[dn] =>
)
)
[b] => Bon Object
(
[n] => id
[v] => 1
[dv] =>
[dn] =>
)
[k] => 0
[row] => Array
(
[aid] => 1
[bonus] => spell.id: 125;
[req] =>
[brcache] =>
[auto] => 0
)
[sp] =>
)
<?php
$str = ob_get_contents();
ob_end_clean();
debug_var('locals', $str);
function debug_var($name,$data)
{
$captured = preg_split("/\r?\n/",$data);
print "<script>function toggleDiv(num){
var span = document.getElementById('d'+num);
var a = document.getElementById('a'+num);
var cur = span.style.display;
if(cur == 'none'){
a.innerHTML = '-';
span.style.display = 'inline';
}else{
a.innerHTML = '+';
span.style.display = 'none';
}
}</script>";
print "<b>$name</b>\n";
print "<pre>\n";
foreach($captured as $line)
{
print debug_colorize_string($line)."\n";
}
print "</pre>\n";
}
function next_div($matches)
{
static $num = 0;
++$num;
return "$matches[1]<a id=a$num href=\"javascript: toggleDiv($num)\">+</a><span id=d$num style=\"display:none\">(";
}
/**
* colorize a string for pretty display
*
* @access private
* @param $string string info to colorize
* @return string HTML colorized
* @global
*/
function debug_colorize_string($string)
{
$string = preg_replace("/\[(\w*)\]/i", '[<font color="red">$1</font>]', $string);
$string = preg_replace_callback("/(\s+)\($/", 'next_div', $string);
$string = preg_replace("/(\s+)\)$/", '$1)</span>', $string);
/* turn array indexes to red */
/* turn the word Array blue */
$string = str_replace('Array','<font color="blue">Array</font>',$string);
/* turn arrows graygreen */
$string = str_replace('=>','<font color="#556F55">=></font>',$string);
return $string;
}
?>
This example uses ideas from this article:
http://www.zend.com/zend/tut/tutorial-DebugLib.php
Print arrays formatted for a browser easily:
<?php
function print_html_r( $aData ) {
echo nl2br( eregi_replace( " ", " ", print_r( $data, TRUE ) ) );
}
?>
You can't use print_r($var, TRUE) inside a function which is a callback from ob_start() or you get the following error:
Fatal error: print_r(): Cannot use output buffering in output buffering display handlers
A simple function to send the output of print_r to firebug.
The script creates a dummy console object with a log method for when firebug is disabled/not available.
<?php
function debug ($data) {
echo "<script>\r\n//<![CDATA[\r\nif(!console){var console={log:function(){}}}";
$output = explode("\n", print_r($data, true));
foreach ($output as $line) {
if (trim($line)) {
$line = addslashes($line);
echo "console.log(\"{$line}\");";
}
}
echo "\r\n//]]>\r\n</script>";
}
?>
I use this all the time when debugging objects, but when you have a very large object with big arrays of sub-objects, it's easy to get overwhelmed with the large amount of output....sometimes you don't want to see absolutely every sub-object.
I made this function to debug objects while "hiding" sub-objects of certain types. This also color codes the output for a more readable printout.
<?php
function wtf($var, $arrayOfObjectsToHide=null, $fontSize=11)
{
$text = print_r($var, true);
if (is_array($arrayOfObjectsToHide)) {
foreach ($arrayOfObjectsToHide as $objectName) {
$searchPattern = '#('.$objectName.' Object\n(\s+)\().*?\n\2\)\n#s';
$replace = "$1<span style=\"color: #FF9900;\">--> HIDDEN - courtesy of wtf() <--</span>)";
$text = preg_replace($searchPattern, $replace, $text);
}
}
// color code objects
$text = preg_replace('#(\w+)(\s+Object\s+\()#s', '<span style="color: #079700;">$1</span>$2', $text);
// color code object properties
$text = preg_replace('#\[(\w+)\:(public|private|protected)\]#', '[<span style="color: #000099;">$1</span>:<span style="color: #009999;">$2</span>]', $text);
echo '<pre style="font-size: '.$fontSize.'px; line-height: '.$fontSize.'px;">'.$text.'</pre>';
}
// example usage:
wtf($myBigObject, array('NameOfObjectToHide_1', 'NameOfObjectToHide_2'));
?>
The following will output an array in a PHP parsable format:
<?php
function serialize_array(&$array, $root = '$root', $depth = 0)
{
$items = array();
foreach($array as $key => &$value)
{
if(is_array($value))
{
serialize_array($value, $root . '[\'' . $key . '\']', $depth + 1);
}
else
{
$items[$key] = $value;
}
}
if(count($items) > 0)
{
echo $root . ' = array(';
$prefix = '';
foreach($items as $key => &$value)
{
echo $prefix . '\'' . $key . '\' => \'' . addslashes($value) . '\'';
$prefix = ', ';
}
echo ');' . "\n";
}
}
?>
Here is a print_r that produces xml:
(now you can expand/collapse the nodes in your browser)
<?php
header('Content-Type: text/xml; charset=UTF-8');
echo print_r_xml($some_var);
function print_r_xml($arr,$first=true) {
$output = "";
if ($first) $output .= "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<data>\n";
foreach($arr as $key => $val) {
if (is_numeric($key)) $key = "arr_".$key; // <0 is not allowed
switch (gettype($val)) {
case "array":
$output .= "<".htmlspecialchars($key)." type='array' size='".count($val)."'>".
print_r_xml($val,false)."</".htmlspecialchars($key).">\n"; break;
case "boolean":
$output .= "<".htmlspecialchars($key)." type='bool'>".($val?"true":"false").
"</".htmlspecialchars($key).">\n"; break;
case "integer":
$output .= "<".htmlspecialchars($key)." type='integer'>".
htmlspecialchars($val)."</".htmlspecialchars($key).">\n"; break;
case "double":
$output .= "<".htmlspecialchars($key)." type='double'>".
htmlspecialchars($val)."</".htmlspecialchars($key).">\n"; break;
case "string":
$output .= "<".htmlspecialchars($key)." type='string' size='".strlen($val)."'>".
htmlspecialchars($val)."</".htmlspecialchars($key).">\n"; break;
default:
$output .= "<".htmlspecialchars($key)." type='unknown'>".gettype($val).
"</".htmlspecialchars($key).">\n"; break;
}
}
if ($first) $output .= "</data>\n";
return $output;
}
?>
I always use this function in my code, because most of my functions return an Array or Boolean :
<?php
function printr ( $object , $name = '' ) {
print ( '\'' . $name . '\' : ' ) ;
if ( is_array ( $object ) ) {
print ( '<pre>' ) ;
print_r ( $object ) ;
print ( '</pre>' ) ;
} else {
var_dump ( $object ) ;
}
}
?>
( print_r gives no output on FALSE and that can be annoying! )
You cannot use print_r(), var_dump() nor var_export() to get static member variables of a class. However, in PHP5 you can use Reflection classes for this:
<?php
$reflection = new ReflectionClass('Static');
print_r($reflection->getStaticProperties());
?>
For those of you needing to print an array within a buffer callback function, I've created this quick function. It simply returns the array as a readable string rather than printing it. You can even choose whether to return it in normal text-mode or HTML. It's recursive, so multi-dimensial arrays are supported. I hope someone finds this useful!
<?php
function return_array($array, $html = false, $level = 0) {
$space = $html ? " " : " ";
$newline = $html ? "<br />" : "\n";
for ($i = 1; $i <= 6; $i++) {
$spaces .= $space;
}
$tabs = $spaces;
for ($i = 1; $i <= $level; $i++) {
$tabs .= $spaces;
}
$output = "Array" . $newline . $newline;
foreach($array as $key => $value) {
if (is_array($value)) {
$level++;
$value = return_array($value, $html, $level);
$level--;
}
$output .= $tabs . "[" . $key . "] => " . $value . $newline;
}
return $output;
}
?>
I was having problems using print_r because I didn't like the fact that if tags where included in the array it would still be parsed by the browsers.
Heres a simple fix for anyone who is having the same problem as I did. This will output your text properly for viewing through the browser instead of the browser's "view source" or CLI.
Script:
<?php
$MyArray[0]="<div align='center'>My Text</div>";
echo "<pre>".htmlspecialchars(print_r($MyArray,true))."</pre>";
?>
Output:
<pre>Array
(
[0] => <div align='center'>My Text</div>
)
</pre>
Another slight modification to the previous post to allow for empty array elements
added the following lines after the first preg_match block
<?php
} else if ($expecting == 2 && preg_match('/^\[(.+?)\] \=\>$/', $trim, $matches)) { // array element
// the array element is blank
list ($fullMatch, $key) = $matches;
$topArray[$key] = $element;
}
?>
Another attempt that tries to overcome the memory blowout when the passed in data has mutual recursion.
<?php
function safe_print_r($data, $nesting = 5, $indent = '') {
if (! is_object($data) && ! is_array($data)) {
var_dump($data);
} elseif ($nesting < 0) {
echo "** MORE **\n";
} else {
echo ucfirst(gettype($data)) . " (\n";
foreach ((array) $data as $k => $v) {
echo $indent . "\t[$k] => ";
safe_print_r($v, $nesting - 1, "$indent\t");
}
echo "$indent)\n";
}
}
?>
I've seen a lot of tries to give an easy way to output the "print_r" info in a decent way in you favorite browser.
Here's mine:
echo ("<pre>");
print_r("-->here goes your data to output<--");
echo ("<pre>");
I personaly think this is the easyest way.
Grz
This is an update from Matt's print_r_reverse() solution that works not only with Arrays, but also with stdClass objects.
I expect someone finds it useful.
<?php
function print_r_reverse($in) {
$lines = explode("\n", trim($in));
if ( (trim($lines[0]) != 'Array') && (trim($lines[0]) != 'stdClass Object') ){
// bottomed out to something that isn't an array or object
return $in;
} else {
// this is an array or stdClass object, lets parse it
if (preg_match("/(\s{4,})\(/", $lines[1], $match)) {
// this is a tested array/recursive call to this function
// take a set of spaces off the beginning
$spaces = $match[1];
$spaces_length = strlen($spaces);
$lines_total = count($lines);
for ($i = 0; $i < $lines_total; $i++) {
if (substr($lines[$i], 0, $spaces_length) == $spaces) {
$lines[$i] = substr($lines[$i], $spaces_length);
}
}
}
$class = trim( $lines[0] );
array_shift($lines); // Array or stdClass Object
array_shift($lines); // (
array_pop($lines); // )
$in = implode("\n", $lines);
// make sure we only match stuff with 4 preceding spaces (stuff for this array and not a nested one)
preg_match_all("/^\s{4}\[(.+?)\] \=\> /m", $in, $matches, PREG_OFFSET_CAPTURE | PREG_SET_ORDER);
$pos = array();
$previous_key = '';
$in_length = strlen($in);
// store the following in $pos:
// array with key = key of the parsed array's item
// value = array(start position in $in, $end position in $in)
foreach ($matches as $match) {
$key = $match[1][0];
$start = $match[0][1] + strlen($match[0][0]);
$pos[$key] = array($start, $in_length);
if ($previous_key != '') $pos[$previous_key][1] = $match[0][1] - 1;
$previous_key = $key;
}
// behave differently depending on the type
switch( $class ){
case 'Array':
$ret = array();
foreach ($pos as $key => $where) {
// recursively see if the parsed out value is an array/object too
$ret[$key] = print_r_reverse(substr($in, $where[0], $where[1] - $where[0]));
}
break;
case 'stdClass Object':
$ret = new stdClass();
foreach ($pos as $key => $where) {
// recursively see if the parsed out value is an array/object too
$ret->$key = print_r_reverse(substr($in, $where[0], $where[1] - $where[0]));
}
break;
default:
throw new Exception( 'Type not allowed' );
}
return $ret;
}
}
?>
This is a happy medium between the overly complex usages and the simplistic. It prints out the debug in a black and green monochrome look.
function formatDebug($value, $log=false) {
$contents = print_r($value, true);
$line="\n"
."<pre style=\"margin:18px 4px; padding:6px; text-align:left; background:#000; color:#00FF00; font-family:courier;\">";
.htmlspecialchars($contents,ENT_QUOTES) // Escape HTML special chars
."</pre>";
if($log==true){
error_log($contents);//Send to log
}
return $line;
}
function : debug_print
<?php
// --------------------------------------------------------------
function debug_print($var, $nfo='DEBUG', $htm=false, $ret=false) {
$var_str = print_r($var, true);
if ($htm !== false) { $var_str = htmlentities($var_str); }
$outstr = '';
$outstr = '<p>--------- <strong>'.$nfo.'</strong> ---------</p>'."\n";
$outstr .= '<pre style="margin:18px 4px; padding:6px; text-align:left; background:#DEDEDE; color:#000099;">'."\n";
$outstr .= $var_str."\n";
$outstr .= '</pre>'."\n";
if ($ret !== false) { $result = $outstr; }
else { print $outstr; $result = true; }
return $result;
}
// --------------------------------------------------------------
?>
usage:
<?php
// --------------------------------------------
$data = array('some', 'example', 'test');
// --- direct output ---
debug_print($data);
// --- returned output ---
$debug_str = debug_print($data, 'some text', false, true);
print $debug_str;
// --------------------------------------------
?>
print_r is used for debug purposes. Yet I had some classes where I just wanted the values coming out of the database, not all the other crap. thus i wrote the following function. If your class has an toArray function, that one will be called otherwise it will return the object as is. print_neat_classes_r is the function that should be called!
<?php
print_neat_classes_r($array, $return=false){
return print_r(self::neat_class_print_r($array), $return);
}
function do_print_r($array, $return=false){
if(is_object($array) && method_exists($array, 'toArray')){
return $array->toArray();
}else if(is_array($array)){
foreach($array as $key=>$obj){
$array[$key] = self::do_print_r($obj, $return);
}
return $array;
}else{
return $array;
}
}
?>
Here is a nice version of print_r that prints things with colors and tables.
I've called it print_nice
<?php
function print_nice($elem,$max_level=10,$print_nice_stack=array()){
if(is_array($elem) || is_object($elem)){
if(in_array(&$elem,$print_nice_stack,true)){
echo "<font color=red>RECURSION</font>";
return;
}
$print_nice_stack[]=&$elem;
if($max_level<1){
echo "<font color=red>nivel maximo alcanzado</font>";
return;
}
$max_level--;
echo "<table border=1 cellspacing=0 cellpadding=3 width=100%>";
if(is_array($elem)){
echo '<tr><td colspan=2 style="background-color:#333333;"><strong><font color=white>ARRAY</font></strong></td></tr>';
}else{
echo '<tr><td colspan=2 style="background-color:#333333;"><strong>';
echo '<font color=white>OBJECT Type: '.get_class($elem).'</font></strong></td></tr>';
}
$color=0;
foreach($elem as $k => $v){
if($max_level%2){
$rgb=($color++%2)?"#888888":"#BBBBBB";
}else{
$rgb=($color++%2)?"#8888BB":"#BBBBFF";
}
echo '<tr><td valign="top" style="width:40px;background-color:'.$rgb.';">';
echo '<strong>'.$k."</strong></td><td>";
print_nice($v,$max_level,$print_nice_stack);
echo "</td></tr>";
}
echo "</table>";
return;
}
if($elem === null){
echo "<font color=green>NULL</font>";
}elseif($elem === 0){
echo "0";
}elseif($elem === true){
echo "<font color=green>TRUE</font>";
}elseif($elem === false){
echo "<font color=green>FALSE</font>";
}elseif($elem === ""){
echo "<font color=green>EMPTY STRING</font>";
}else{
echo str_replace("\n","<strong><font color=red>*</font></strong><br>\n",$elem);
}
}
?>
If you have to catch the output without showing it at all at first (for example, if you want to append the print_r output to a file), you can do this:
<?php
ob_start();
print_r( $some_array );
$output = ob_get_clean();
// if you want to append the print_r output of $some_array to, let's say, log.txt:
file_put_contents( 'log.txt', file_get_contents( 'log.txt' ) . $output )
?>
This is an alternative for printing arrays. It bolds array values.
<?php
function print_array(&$a, $str = "")
{
if ($str[0]) {
echo "$str =";
}
echo ' array( ';
foreach ($a as $k => $v) {
echo "[$k]".' => ';
if (is_array($v)) {
print_array($v);
}
else {
echo "<strong>$a[$k]</strong> ";
}
}
echo ') ';
}
$a1 = array ("apples", "oranges", "pears");
$a2 = array ("potatos", "green beans", "squash");
$a3 = array ("euros", "dollars", "pesos", "dinars");
$test = range(1, 9);
array_push($test, array ("fruit" => $a1, "vegies" => $a2, "money" => $a3));
print_array($test, "test");
?>
I have written a nice debugging function.
This function handles arrays beautifully.
<?php
//Debug variables, $i and $k are for recursive use
function DebugDisplayVar($input, $name = "Debug", $i = "0", $k = array("Error")){
if(is_array($input))
{ foreach ($input as $i => $value){
$temp = $k;
$temp[] = $i;
DebugDisplayVar($value, $name, $i, $temp);}
}else{//if not array
echo "$".$name;//[$k]
foreach ($k as $i => $value){
if($value !=="Error"){echo "[$value]";}
}
echo " = $input<br>";
} }
//outputs
Debug[0] = value
Debug[1] = another value
ect...
?>
A slight modification to the previous post to allow for arrays containing mutli line strings. haven't fully tested it with everything, but seems to work great for the stuff i've done so far.
<?php
function print_r_reverse(&$output)
{
$expecting = 0; // 0=nothing in particular, 1=array open paren '(', 2=array element or close paren ')'
$lines = explode("\n", $output);
$result = null;
$topArray = null;
$arrayStack = array();
$matches = null;
while (!empty($lines) && $result === null)
{
$line = array_shift($lines);
$trim = trim($line);
if ($trim == 'Array')
{
if ($expecting == 0)
{
$topArray = array();
$expecting = 1;
}
else
{
trigger_error("Unknown array.");
}
}
else if ($expecting == 1 && $trim == '(')
{
$expecting = 2;
}
else if ($expecting == 2 && preg_match('/^\[(.+?)\] \=\> (.+)$/', $trim, $matches)) // array element
{
list ($fullMatch, $key, $element) = $matches;
if (trim($element) == 'Array')
{
$topArray[$key] = array();
$newTopArray =& $topArray[$key];
$arrayStack[] =& $topArray;
$topArray =& $newTopArray;
$expecting = 1;
}
else
{
$topArray[$key] = $element;
}
}
else if ($expecting == 2 && $trim == ')') // end current array
{
if (empty($arrayStack))
{
$result = $topArray;
}
else // pop into parent array
{
// safe array pop
$keys = array_keys($arrayStack);
$lastKey = array_pop($keys);
$temp =& $arrayStack[$lastKey];
unset($arrayStack[$lastKey]);
$topArray =& $temp;
}
}
// Added this to allow for multi line strings.
else if (!empty($trim) && $expecting == 2)
{
// Expecting close parent or element, but got just a string
$topArray[$key] .= "\n".$line;
}
else if (!empty($trim))
{
$result = $line;
}
}
$output = implode(n, $lines);
return $result;
}
/**
* @param string $output : The output of a multiple print_r calls, separated by newlines
* @return mixed[] : parseable elements of $output
*/
function print_r_reverse_multiple($output)
{
$result = array();
while (($reverse = print_r_reverse($output)) !== NULL)
{
$result[] = $reverse;
}
return $result;
}
$output = '
Array
(
[a] => apple
[b] => banana
[c] => Array
(
[0] => x
[1] => y
[2] => z
[3] => Array
(
[nest] => yes
[nest2] => Array
(
[nest] => some more
asffjaskkd
)
[nest3] => o rly?
)
)
)
some extra stuff
';
var_dump(print_r_reverse($output), $output);
?>
This should output
array(3) {
["a"]=>
string(5) "apple"
["b"]=>
string(6) "banana"
["c"]=>
array(4) {
[0]=>
string(1) "x"
[1]=>
string(1) "y"
[2]=>
string(1) "z"
[3]=>
array(3) {
["nest"]=>
string(3) "yes"
["nest2"]=>
array(1) {
["nest"]=>
string(40) "some more
asffjaskkd"
}
["nest3"]=>
string(6) "o rly?"
}
}
}
string(18) "nsome extra stuffn"
Added:
else if (!empty($trim) && $expecting == 2)
{
// Expecting close parent or element, but got just a string
$topArray[$key] .= "\n".$line;
}
This is a better print_r reverse algorithm, that works with arbitrary nested arrays. Anything else it treats as strings. The second function allows you to take a string with multiple print_r results concatenated, and returns the result of parsing each of them.
<?php
/**
* @param string &$output : The output of a print_r call; this parameter is DESTRUCTIVE, and will be set to the remainder
* of $output which is not parsed.
* @return mixed : the first parseable element of $output
*/
function print_r_reverse(&$output)
{
$expecting = 0; // 0=nothing in particular, 1=array open paren '(', 2=array element or close paren ')'
$lines = explode("\n", $output);
$result = null;
$topArray = null;
$arrayStack = array();
$matches = null;
while (!empty($lines) && $result === null)
{
$line = array_shift($lines);
$trim = trim($line);
if ($trim == 'Array')
{
if ($expecting == 0)
{
$topArray = array();
$expecting = 1;
}
else
{
trigger_error("Unknown array.");
}
}
else if ($expecting == 1 && $trim == '(')
{
$expecting = 2;
}
else if ($expecting == 2 && preg_match('/^\[(.+?)\] \=\> (.+)$/', $trim, $matches)) // array element
{
list ($fullMatch, $key, $element) = $matches;
if (trim($element) == 'Array')
{
$topArray[$key] = array();
$newTopArray =& $topArray[$key];
$arrayStack[] =& $topArray;
$topArray =& $newTopArray;
$expecting = 1;
}
else
{
$topArray[$key] = $element;
}
}
else if ($expecting == 2 && $trim == ')') // end current array
{
if (empty($arrayStack))
{
$result = $topArray;
}
else // pop into parent array
{
// safe array pop
$keys = array_keys($arrayStack);
$lastKey = array_pop($keys);
$temp =& $arrayStack[$lastKey];
unset($arrayStack[$lastKey]);
$topArray =& $temp;
}
}
else if (!empty($trim))
{
$result = $line;
}
}
$output = implode(n, $lines);
return $result;
}
/**
* @param string $output : The output of a multiple print_r calls, separated by newlines
* @return mixed[] : parseable elements of $output
*/
function print_r_reverse_multiple($output)
{
$result = array();
while (($reverse = print_r_reverse($output)) !== NULL)
{
$result[] = $reverse;
}
return $result;
}
$output = '
Array
(
[a] => apple
[b] => banana
[c] => Array
(
[0] => x
[1] => y
[2] => z
[3] => Array
(
[nest] => yes
[nest2] => Array
(
[nest] => some more
)
[nest3] => o rly?
)
)
)
some extra stuff
';
var_dump(print_r_reverse($output), $output);
?>
The above example will output:
array(3) {
["a"]=>
string(5) "apple"
["b"]=>
string(6) "banana"
["c"]=>
array(4) {
[0]=>
string(1) "x"
[1]=>
string(1) "y"
[2]=>
string(1) "z"
[3]=>
array(3) {
["nest"]=>
string(3) "yes"
["nest2"]=>
array(1) {
["nest"]=>
string(9) "some more"
}
["nest3"]=>
string(6) "o rly?"
}
}
}
string(20) "
some extra stuff
"
If you need to import an print_R output back to an array you could use this.
This could also be (ab)used to convert a object into a array...
<?php
function object2array($printr) {
$newarray = array();
$a[0] = &$newarray;
if (preg_match_all('/^\s+\[(\w+).*\] => (.*)\n/m', $printr, $match)) {
foreach ($match[0] as $key => $value) {
(int)$tabs = substr_count(substr($value, 0, strpos($value, "[")), " ");
if ($match[2][$key] == 'Array' || substr($match[2][$key], -6) == 'Object') {
$a[$tabs+1] = &$a[$tabs][$match[1][$key]];
}
else {
$a[$tabs][$match[1][$key]] = $match[2][$key];
}
}
}
return $newarray;
}
?>
This works around the hacky nature of print_r in return mode (using output buffering for the return mode to work is hacky...):
<?php
/**
* An alternative to print_r that unlike the original does not use output buffering with
* the return parameter set to true. Thus, Fatal errors that would be the result of print_r
* in return-mode within ob handlers can be avoided.
*
* Comes with an extra parameter to be able to generate html code. If you need a
* human readable DHTML-based print_r alternative, see http://krumo.sourceforge.net/
*
* Support for printing of objects as well as the $return parameter functionality
* added by Fredrik Wollsén (fredrik dot motin at gmail), to make it work as a drop-in
* replacement for print_r (Except for that this function does not output
* paranthesises around element groups... ;) )
*
* Based on return_array() By Matthew Ruivo (mruivo at gmail)
* (http://se2.php.net/manual/en/function.print-r.php#73436)
*/
function obsafe_print_r($var, $return = false, $html = false, $level = 0) {
$spaces = "";
$space = $html ? " " : " ";
$newline = $html ? "<br />" : "\n";
for ($i = 1; $i <= 6; $i++) {
$spaces .= $space;
}
$tabs = $spaces;
for ($i = 1; $i <= $level; $i++) {
$tabs .= $spaces;
}
if (is_array($var)) {
$title = "Array";
} elseif (is_object($var)) {
$title = get_class($var)." Object";
}
$output = $title . $newline . $newline;
foreach($var as $key => $value) {
if (is_array($value) || is_object($value)) {
$level++;
$value = obsafe_print_r($value, true, $html, $level);
$level--;
}
$output .= $tabs . "[" . $key . "] => " . $value . $newline;
}
if ($return) return $output;
else echo $output;
}
?>
Built on a function earlier posted in these comments as stated in the Doc comment. Cheers! /Fredrik (Motin)
We had an interesting problem dumping an object that
contained embedded HTML. The application makes use
of buffer manipulation functions, so print_r's 2nd argument
wasn't helpful. Here is how we solved the problem:
$object = new ObjectContainingHTML();
$savedbuffercontents = ob_get_clean();
print_r($object);
$print_r_output = ob_get_clean();
ob_start();
echo $savedbuffercontents;
echo htmlentities($print_r_output);
For very long arrays I have written a little function which formats an array quite nice and uses javascript for browsing it like a tree. The function is very customizable with the $style parameter.
For me it's of great use for browsing large array's, for example when those are used in language-files in some script and so on. It may even be used in "real" scripts for the "real" front-end, cause the tree can very easily be styled (look at the function or the outputted source and you'll see what i mean).
Here's the function:
<?php
function print_r_html($arr, $style = "display: none; margin-left: 10px;")
{ static $i = 0; $i++;
echo "\n<div id=\"array_tree_$i\" class=\"array_tree\">\n";
foreach($arr as $key => $val)
{ switch (gettype($val))
{ case "array":
echo "<a onclick=\"document.getElementById('";
echo array_tree_element_$i."').style.display = ";
echo "document.getElementById('array_tree_element_$i";
echo "').style.display == 'block' ?";
echo "'none' : 'block';\"\n";
echo "name=\"array_tree_link_$i\" href=\"#array_tree_link_$i\">".htmlspecialchars($key)."</a><br />\n";
echo "<div class=\"array_tree_element_\" id=\"array_tree_element_$i\" style=\"$style\">";
echo print_r_html($val);
echo "</div>";
break;
case "integer":
echo "<b>".htmlspecialchars($key)."</b> => <i>".htmlspecialchars($val)."</i><br />";
break;
case "double":
echo "<b>".htmlspecialchars($key)."</b> => <i>".htmlspecialchars($val)."</i><br />";
break;
case "boolean":
echo "<b>".htmlspecialchars($key)."</b> => ";
if ($val)
{ echo "true"; }
else
{ echo "false"; }
echo "<br />\n";
break;
case "string":
echo "<b>".htmlspecialchars($key)."</b> => <code>".htmlspecialchars($val)."</code><br />";
break;
default:
echo "<b>".htmlspecialchars($key)."</b> => ".gettype($val)."<br />";
break; }
echo "\n"; }
echo "</div>\n"; }
?>
The function as it is now does not support the $return parameter as print_r does and will create an endless loop like print_r did in php-versions < 4.0.3 when there is an element which contains a reference to a variable inside of the array to print out :-/
I've tested it with PHP 5.0.6 and PHP 4.2.3 - no problems except those already mentioned.
please e-mail me if you've got a solution for the problems i've mentioned, i myself are not able to solve them 'cause i don't know how the hell i can find out whether a variable is a reference or not.
Do you think it is difficult to see what print_r() returns?
<?php
echo '<pre>';
print_r($array);
echo '</pre>';
?>
And if you have to write this many times in a page, use this:
<?php
function preint_r($array)
{
echo '<pre>';
print_r($array);
echo '</pre>';
}
?>
Here is a print_r() clone but support max level limit.
When we want to print a big object, this will help us get a clean dumping data.
<?php
/**
* Recrusive print variables and limit by level.
*
* @param mixed $data The variable you want to dump.
* @param int $level The level number to limit recrusive loop.
*
* @return string Dumped data.
*
* @author Simon Asika (asika32764[at]gmail com)
* @date 2013-11-06
*/
function print_r_level($data, $level = 5)
{
static $innerLevel = 1;
static $tabLevel = 1;
static $cache = array();
$self = __FUNCTION__;
$type = gettype($data);
$tabs = str_repeat(' ', $tabLevel);
$quoteTabes = str_repeat(' ', $tabLevel - 1);
$recrusiveType = array('object', 'array');
// Recrusive
if (in_array($type, $recrusiveType))
{
// If type is object, try to get properties by Reflection.
if ($type == 'object')
{
if (in_array($data, $cache))
{
return "\n{$quoteTabes}*RECURSION*\n";
}
// Cache the data
$cache[] = $data;
$output = get_class($data) . ' ' . ucfirst($type);
$ref = new \ReflectionObject($data);
$properties = $ref->getProperties();
$elements = array();
foreach ($properties as $property)
{
$property->setAccessible(true);
$pType = $property->getName();
if ($property->isProtected())
{
$pType .= ":protected";
}
elseif ($property->isPrivate())
{
$pType .= ":" . $property->class . ":private";
}
if ($property->isStatic())
{
$pType .= ":static";
}
$elements[$pType] = $property->getValue($data);
}
}
// If type is array, just retun it's value.
elseif ($type == 'array')
{
$output = ucfirst($type);
$elements = $data;
}
// Start dumping datas
if ($level == 0 || $innerLevel < $level)
{
// Start recrusive print
$output .= "\n{$quoteTabes}(";
foreach ($elements as $key => $element)
{
$output .= "\n{$tabs}[{$key}] => ";
// Increment level
$tabLevel = $tabLevel + 2;
$innerLevel++;
$output .= in_array(gettype($element), $recrusiveType) ? $self($element, $level) : $element;
// Decrement level
$tabLevel = $tabLevel - 2;
$innerLevel--;
}
$output .= "\n{$quoteTabes})\n";
}
else
{
$output .= "\n{$quoteTabes}*MAX LEVEL*\n";
}
}
// Clean cache
if($innerLevel == 1)
{
$cache = array();
}
return $output;
}// End function
// TEST ------------------------------------
class testClass
{
protected $a = 'aaa';
private $b = 'bbb';
public $c = array(1, 2, ['a', 'b', 'c'], 4);
static public $d = 'ddd';
static protected $e = 'eee';
}
$test = new testClass;
$test->testClass = $test;
echo '<pre>' . print_r_level($test, 3) . '</pre>';
?>
will output
-------------------------------------------------------------
testClass Object
(
[a:protected] => aaa
[b:testClass:private] => bbb
[c] => Array
(
[0] => 1
[1] => 2
[2] => Array
*MAX LEVEL*
[3] => 4
)
[d:static] => ddd
[e:protected:static] => eee
[testClass] =>
*RECURSION*
)
A simple function that will output an array more easily to read than print_r();
<?php
function echo_array($array,$return_me=false){
if(is_array($array) == false){
$return = "The provided variable is not an array.";
}else{
foreach($array as $name=>$value){
if(is_array($value)){
$return .= "";
$return .= "['<b>$name</b>'] {<div style='margin-left:10px;'>\n";
$return .= echo_array($value,true);
$return .= "</div>}";
$return .= "\n\n";
}else{
if(is_string($value)){
$value = "\"$value\"";
}
$return .= "['<b>$name</b>'] = $value\n\n";
}
}
}
if($return_me == true){
return $return;
}else{
echo "<pre>".$return."</pre>";
}
}
?>
Bear in mind that print_r actually reserves some memory to do something - so, for example thing like:
<?php
function shutdown_handler()
{
file_put_contents($_SERVER['DOCUMENT_ROOT']."/log.txt", print_r($_REQUEST, true));
}
ini_set('memory_limit', '1M');
register_shutdown_function("shutdown_handler");
$array = array();
while(true)
$array[] = new stdClass();
?>
will just not work. Try using var_export, and presto, everything is fine.
my take on the highlighted markupped debug function:
<?php
/**
* print_array()
* Does a var_export of the array and returns it between <pre> tags
*
* @param mixed $var any input you can think of
* @return string HTML
*/
function print_array($var)
{
$input =var_export($var,true);
$input = preg_replace("! => \n\W+ array \(!Uims", " => Array ( ", $input);
$input = preg_replace("!array \(\W+\),!Uims", "Array ( ),", $input);
return("<pre>".str_replace('><?', '>', highlight_string('<'.'?'.$input, true))."</pre>");
}
?>
Here's a PHP version of print_r which can be tailored to your needs. Shows protected and private properties of objects and detects recursion (for objects only!). Usage:
void u_print_r ( mixed $expression [, array $ignore] )
Use the $ignore parameter to provide an array of property names that shouldn't be followed recursively.
<?php
function u_print_r($subject, $ignore = array(), $depth = 1, $refChain = array())
{
if ($depth > 20) return;
if (is_object($subject)) {
foreach ($refChain as $refVal)
if ($refVal === $subject) {
echo "*RECURSION*\n";
return;
}
array_push($refChain, $subject);
echo get_class($subject) . " Object ( \n";
$subject = (array) $subject;
foreach ($subject as $key => $val)
if (is_array($ignore) && !in_array($key, $ignore, 1)) {
echo str_repeat(" ", $depth * 4) . '[';
if ($key{0} == "\0") {
$keyParts = explode("\0", $key);
echo $keyParts[2] . (($keyParts[1] == '*') ? ':protected' : ':private');
} else
echo $key;
echo '] => ';
u_print_r($val, $ignore, $depth + 1, $refChain);
}
echo str_repeat(" ", ($depth - 1) * 4) . ")\n";
array_pop($refChain);
} elseif (is_array($subject)) {
echo "Array ( \n";
foreach ($subject as $key => $val)
if (is_array($ignore) && !in_array($key, $ignore, 1)) {
echo str_repeat(" ", $depth * 4) . '[' . $key . '] => ';
u_print_r($val, $ignore, $depth + 1, $refChain);
}
echo str_repeat(" ", ($depth - 1) * 4) . ")\n";
} else
echo $subject . "\n";
}
?>
Example:
<?php
class test {
public $var1 = 'a';
protected $var2 = 'b';
private $var3 = 'c';
protected $array = array('x', 'y', 'z');
}
$test = new test();
$test->recursiveRef = $test;
$test->anotherRecursiveRef->recursiveRef = $test;
$test->dont->follow = 'me';
u_print_r($test, array('dont'));
?>
Will produce:
test Object (
[var1] => a
[var2:protected] => b
[var3:private] => c
[array:protected] => Array (
[0] => x
[1] => y
[2] => z
)
[recursiveRef] => *RECURSION*
[anotherRecursiveRef] => stdClass Object (
[recursiveRef] => *RECURSION*
)
)
Bases on thbley´s sript i use this one to log some actions.
It will return a tabbed like string which you can output or whatever.
Input fields like "Password" will not be shown.
<?php
function print_r_string($arr,$first=true,$tab=0)
{
$output = "";
$tabsign = ($tab) ? str_repeat(' ',$tab) : '';
if ($first) $output .= "<pre><br>\n";
foreach($arr as $key => $val)
{
switch (gettype($val))
{
case "array":
$output .= $tabsign."[".htmlspecialchars($key)."] = array(".count($val).")<br>\n".$tabsign."(<br>\n";
$tab++;
$output .= print_r_string($val,false,$tab);
$tab--;
$output .= $tabsign.")<br>\n";
break;
case "boolean":
$output .= $tabsign."[".htmlspecialchars($key)."] bool = '".($val?"true":"false")."'<br>\n";
break;
case "integer":
$output .= $tabsign."[".htmlspecialchars($key)."] int = '".htmlspecialchars($val)."'<br>\n";
break;
case "double":
$output .= $tabsign."[".htmlspecialchars($key)."] double = '".htmlspecialchars($val)."'<br>\n";
break;
case "string":
$output .= $tabsign."[".htmlspecialchars($key)."] string = '".((stristr($key,'passw')) ? str_repeat('*', strlen($val)) : htmlspecialchars($val))."'<br>\n";
break;
default:
$output .= $tabsign."[".htmlspecialchars($key)."] unknown = '".htmlspecialchars(gettype($val))."'<br>\n";
break;
}
}
if ($first) $output .= "</pre><br>\n";
return $output;
}
echo print_r_string(array($_POST,$_GET)); // for Example
?>
Here's an array_depth() function that calculates the depth of an array using the indentation in the output of print_r():
<?php
function array_depth($array) {
$max_indentation = 1;
$array_str = print_r($array, true);
$lines = explode("\n", $array_str);
foreach ($lines as $line) {
$indentation = (strlen($line) - strlen(ltrim($line))) / 4;
if ($indentation > $max_indentation) {
$max_indentation = $indentation;
}
}
return ceil(($max_indentation - 1) / 2) + 1;
}
?>
It's better than writing a recursive function to do the same thing, as print_r() handles the problem of infinitely-deep arrays for you quite nicely.
There is a library to create nice output of variables, arrays, hash-tables and even objects. It is great for developing/debugging and looks very much better than any print_r output.
Usage:
<?php
debug::show($myVar, 'caption');
?>
You can download it for free at http://sourceforge.net/projects/phpcorestdfuncs
For an example take a look at http://demo.corvent.ch/stdfuncs/
print_r(), just like var_dump() does NOT cast an object, not even if it has a __toString() method - which is normal.
<?php
class A {
public function __toString() {
return 'In class A';
}
}
$a = new A;
echo $a; // In class A
print_r($a); // A Object()
// you can simulate the echo by casting it manually
print_r((string)$a); // In class A
i've been using a similar idea like Sawey's for quite a long time,
but was always disappointed that you don't see the name of the
variable passed to the function (eg calling it many times, you don't
know which value was provided by a certain variable at a certain time).
so i combined sawey's idea with one found on php.net to solve that problem.
for shellscripting the function only uses <pre>-tags when called in the web.
<?php
/* how print_r should be ;) */
function my_r(&$var, $scope=false, $label=false){
if (is_string($scope) && $label==false) $label=$scope;
if (!is_array($scope)) $scope = &$GLOBALS;
$origin = $var;
$var = $checker = "very_weird_value#".rand()."#isnt_it";
$vname = false;
foreach ($scope as $key => $value){
if ($value === $checker){ $vname = "\$".$key; }
if (is_array($value) && $key!="GLOBALS"){
if ($pfad=aver($var,$value)){
$vname = "\$${key}[\"". implode("\"][\"",$pfad)."\"]";
}
}
if (is_object($value)){
if ($pfad=aver($var,get_object_vars($value))){
if (sizeof($pfad)<2) $vname = "\$${key}->".$pfad[0];
else{
$vname ="\$${key}->".$pfad[0];
$vname.="[\"".implode("\"][\"", array_slice($pfad,1))."\"]";
}
}
}
if ($vname) break;
}
$var = $origin;
if ($_SERVER["SERVER_NAME"] && !isset($_SERVER["TERM"])) echo "<pre>";
if ($vname){
echo $vname;
if ($label) echo " #" . $label . "# ";
else echo ": ";
}else{
if ($label) echo "$label: ";
}
print_r($var);
if ($_SERVER["SERVER_NAME"] && !isset($_SERVER["TERM"])) echo "</pre>";
}
/* this function is needed to check in multidimensional arrays
if the value of interest exists. if yes, the path is returned */
function aver($needle,$haystack) { // array value exists recursive
foreach($haystack as $key=>$val) {
if(is_array($val) && $needle != $val && $key != "GLOBALS") {
if($foo=aver($needle,$val)) return array_merge(array($key),$foo);
}elseif($val === $needle) return array($key);
}
return false;
}
?>
<?php
// Displays a multi-dimensional array as a HTML List (Tree structure).
function displayTree($var) {
$newline = "\n";
foreach($var as $key => $value) {
if (is_array($value) || is_object($value)) {
$value = $newline . "<ul>" . displayTree($value) . "</ul>";
}
if (is_array($var)) {
if (!stripos($value, "<li class=")) {
$output .= "<li class=\"file\">" . $value . "</li>" . $newline;
}
else {
$output .= $value . $newline;
}
}
else { // is_object
if (!stripos($value, "<li class=")) {
$value = "<ul><li class=\"file\">" . $value . "</li></ul>" . $newline;
}
$output .= "<li class=\"folder\">" . $key . $value . "</li>" . $newline;
}
}
return $output;
}
?>
///////////////////
Also need to add this to your style sheet (and get the necessary images...):
li.folder
{
list-style-image: url(../img/folder.gif);
}
li.file
{
list-style-image: url(../img/file.gif);
}
///////////////////
Example Usage:
<?php
...
echo "<ul>";
echo displayTree($array);
echo "</ul>";
?>
If you're like me and just want an exact version of print_r() except formatted to HTML without a bunch of bs, here you go.
The output is identical to print_r() but renders in HTML.
<?php
// Displays a multi-dimensional array as a HTML unordered lists.
function displayTree($array) {
$newline = "<br>";
foreach($array as $key => $value) { //cycle through each item in the array as key => value pairs
if (is_array($value) || is_object($value)) { //if the VALUE is an array, then
//call it out as such, surround with brackets, and recursively call displayTree.
$value = "Array()" . $newline . "(<ul>" . displayTree($value) . "</ul>)" . $newline;
}
//if value isn't an array, it must be a string. output its' key and value.
$output .= "[$key] => " . $value . $newline;
}
return $output;
}
?>
Since i use print_r for debugging a lot, i always use the following function in my scripts, which makes life a lot easier :-)
<?php
if (!function_exists("preprint")) {
function preprint($s, $return=false) {
$x = "<pre>";
$x .= print_r($s, 1);
$x .= "</pre>";
if ($return) return $x;
else print $x;
}
}
?>
-------------------
USAGE: preprint($x); <- where $x = array().
-------------------
The optional 2. parameter can be set to "true", so the html-code is returned.
Have fun,
Sometimes, when page is called by ajax and you're not actually feeling convenient to see output of debugging, you may log it in file like shown below:
<?php
// Log superglobals
$g=print_r($_GET,true);
$p=print_r($_POST,true);
$f=print_r($_FILES,true);
$s=print_r($_SESSION,true);
$txt='';
$txt.="/n".'GET: '.$g;
$txt.="/n".'POST: '.$p;
$txt.="/n".'FILES: '.$f;
$txt.="/n".'SESSION: '.$s;
file_put_contents('requests.txt',$txt);
?>
Many developers have submitted bugs to the PHP development team with regards to print_r showing protected and private properties of objects (PHP 5). This is not a bug; sensitive information (ex. database connection object) should be encapsulated within a private member function of your class.
We can all agree that print_r() output is very spartan looking. The debug data needs to be organized better, and presented in a graceful way. In the era of Web 2.0 it is somewhat strange to use plain text to dump information. A DHTML powered informatiion dumping tool will be quite better - like the the open-source alternative of print_r(); -- Krumo (http://krumo.sourceforge.net).
It renders the output using DHTML and collapsible nodes, it's layout is "skinable" and you can change it to fit your aesthetic taste. Krumo makes the output "human-readable" for real :) Plus it is compliant with both PHP4 and PHP5. Plus it detects "reference recursion". Plus you can use it to dump all various sort of data like debug back-traces, the superglobals ($_SERVER, $_ENV, $_REQUEST, $_COOKIE, $_GET, $_POST, $_SESSION), all the included files, all the declared classes, all the declared constants, all your PHP settings, all your php.ini values (if it is readable), all the loaded extensions, all the HTTP request headers, all the declared interfaces (for PHP5), all the file paths from INCLUDE_PATH, all the values of any particular INI file. Additionally it is designed to be easy to use - for example you can disable all the Krumo dumps instead of cleaning your code out of all print_r()'s and var_dump()'s. Anyway, if you check the site (http://krumo.sourceforge.net), you can found a lot of examples, demonstrations, documentation and all sort of helpful information.
