print_r()
(PHP 4, PHP 5, PHP 7)
以易于理解的格式打印变量。
说明
print_r(mixed $expression[,bool $return=FALSE]): mixed
print_r()以人类易读的格式显示一个变量的信息。
print_r()、var_dump()、var_export()都会显示对象 protected 和 private 的属性。 Class 的静态属性（static）则不会显示。
参数
- $expression
要打印的表达式。
- $return
想要获取print_r()输出的内容，使用$return参数。当此参数为
TRUE，print_r()会直接返回信息，而不是输出。
返回值
如果输入的内容是string、integer或float，会直接输出值本身。如果输入的内容是array，展示的格式会显示数组的键和包含的元素。object也类似。
当$return参数设置成TRUE，本函数会返回string格式。否则返回TRUE。
注释
Note:当使用了$return参数时，本函数使用其内部输出缓冲，因此不能在ob_start()回调函数的内部使用。
范例
Example #1print_r()例子
<pre>
<?php
$a = array ('a' => 'apple', 'b' => 'banana', 'c' => array ('x', 'y', 'z'));
print_r ($a);
?>
</pre>以上例程会输出：
<pre>
Array
(
[a] => apple
[b] => banana
[c] => Array
(
[0] => x
[1] => y
[2] => z
)
)
</pre>
Example #2$return参数的例子
<?php
$b = array ('m' => 'monkey', 'foo' => 'bar', 'x' => array ('x', 'y', 'z'));
$results = print_r($b, true); // $results 包含了 print_r 的输出
?>
参见
ob_start()打开输出控制缓冲var_dump()打印变量的相关信息var_export()输出或返回一个变量的字符串表示
I add this function to the global scope on just about every project I do, it makes reading the output of print_r() in a browser infinitely easier.
<?php
function print_r2($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')I've fixed function wrote by Matt to reverse print_r - it had problems with null values. Created a GIST for that too so please add any future fixes in there instead of this comment section:
https://gist.github.com/simivar/037b13a9bbd53ae5a092d8f6d9828bc3
<?php
/**
* Matt: core
* Trixor: object handling
* lech: Windows suppport
* simivar: null support
*
* @see http://php.net/manual/en/function.print-r.php
**/
function print_r_reverse($input) {
$lines = preg_split('#\r?\n#', trim($input));
if (trim($lines[ 0 ]) != 'Array' && trim($lines[ 0 ] != 'stdClass Object')) {
// bottomed out to something that isn't an array or object
if ($input === '') {
return null;
}
return $input;
} else {
// this is an array or object, lets parse it
$match = array();
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);
}
}
}
$is_object = trim($lines[ 0 ]) == 'stdClass Object';
array_shift($lines); // Array
array_shift($lines); // (
array_pop($lines); // )
$input = implode("\n", $lines);
$matches = array();
// 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", $input, $matches, PREG_OFFSET_CAPTURE | PREG_SET_ORDER);
$pos = array();
$previous_key = '';
$in_length = strlen($input);
// 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[ $key ] = print_r_reverse(substr($input, $where[ 0 ], $where[ 1 ] - $where[ 0 ]));
}
return $is_object ? (object)$ret : $ret;
}
}
?>
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 $output;
}
?>
Built on a function earlier posted in these comments as stated in the Doc comment. Cheers! /Fredrik (Motin)Here is a print_r that produces xml:
(now you can expand/collapse the nodes in your browser)
<?php
header('Content-Type: text/xml; charset=UTF-8');
echo print_r_xml($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 $output;
}
?>
Here is another version that parses the print_r() output. I tried the one posted, but I had difficulties with it. I believe it has a problem with nested arrays. This handles nested arrays without issue as far as I can tell.
<?php
function print_r_reverse($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 $ret;
}
}
?>
The following will output an array in a PHP parsable format:
<?php
function serialize_array(&$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) . '\'';
$prefix = ', ';
}
echo ');' . "\n";
}
}
?>
This is an alternative for printing arrays. It bolds array values.
<?php
function print_array(&$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 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! )Remember to always htmlspecialchars print_r output, if it can contain html characters.
<?php
$array = array("<some>html<tags>");
print_r($array); // Invalid output, HTML breaks.
echo htmlspecialchars(print_r($array, true)); // Works and doesn't break the output.
?>
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 " = $input<br>";
} }
//outputs
Debug[0] = value
Debug[1] = another value
ect...
?>
// New var export option
function varExp($E,$vE){
$vE.="=array(";$sep="";
foreach ($E as $veK => $veV) {
$vE.=$sep."'$veK'=>'$veV'";$sep=",";
}
$vE.=");";
return $vE;
}
print varExp($I,"\$I");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>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 $array;
}
}
?>
A simple function to send the output of print_r to firebug.
The script creates a dummy console object with a log method for when firebug is disabled/not available.
<?php
function debug ($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'));
?>
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());
?>
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>
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;
}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 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*
)I prefer to use
<?php
printf("<pre>%s</pre>",print_r($_POST, true));
?>
For those of you needing to print an array within a buffer callback function, I've created this quick function. It simply returns the array as a readable string rather than printing it. You can even choose whether to return it in normal text-mode or HTML. It's recursive, so multi-dimensial arrays are supported. I hope someone finds this useful!
<?php
function return_array($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;
}
?>
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);
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 AFor 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.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*
)
)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;
}
?>
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' ) . $output ) ?>
You can't use print_r($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
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 "$indent)\n";
}
}
?>
liamtoh6@hotmail.com posted a function that will echo print_r output with proper new lines in HTML files. He used <pre> for it to work, but that might not be always the best method to go. For example, it is not valid to place <pre> inside <p>.
Here is my way to do this:
<?php
function print_rbr ($var, $return = false) {
$r = nl2br(htmlspecialchars(print_r($var, true)));
if ($return) return $r;
else echo $r;
}
?>
This function will:
- Place <br> where newlines are,
- Escape unsecure characters with HTML entities.A slight amendment to Matt's awesome print_r_reverse function (Thank You, a life-saver - data recovery :-) . If the output is copied from a Windows system, the end of lines may include the return character "\r" and so the scalar (string) elements will include a trailing "\r" character that isn't suppose to be there. To resolve, replace the first line in the function with...
<?php $lines = preg_split('#\r?\n#', trim($in)); ?>
This will work for both cases (Linux and Windows).
I include the entire function below for completeness, but all credit to Matt, the original author, Thank You.
<?php
//Author: Matt (http://us3.php.net/print_r)
function print_r_reverse($in) {
$lines = preg_split('#\r?\n#', trim($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 $ret;
}
}
?>
Bear in mind that print_r actually reserves some memory to do something - so, for example thing like:
<?php
function shutdown_handler()
{
file_put_contents($_SERVER['DOCUMENT_ROOT']."/log.txt", print_r($_REQUEST, true));
}
ini_set('memory_limit', '1M');
register_shutdown_function("shutdown_handler");
$array = array();
while(true)
$array[] = new stdClass();
?>
will just not work. Try using var_export, and presto, everything is fine.Many developers have submitted bugs to the PHP development team with regards to print_r showing protected and private properties of objects (PHP 5). This is not a bug; sensitive information (ex. database connection object) should be encapsulated within a private member function of your class.
I've made a small improvement to the print_r_reverse function to also handle objects. Thanks to Matt for making the original.
<?php
function print_r_reverse($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 object, lets parse it
$match = array();
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);
}
}
}
$is_object = trim($lines[0]) == 'stdClass Object';
array_shift($lines); // Array
array_shift($lines); // (
array_pop($lines); // )
$in = implode("\n", $lines);
$matches = array();
// 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 $is_object ? (object) $ret : $ret;
}
}
?>
easier and better readability with print_r and vardump for php developers https://gist.github.com/akwatra/b6a2f21b33e7a86d148618d8a83276b0