PHP: print_r - Manual

Description

bool print_r ( mixed expression [, bool return] )

Замечание: The return parameter was added in PHP 4.3.0

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. print_r() and var_export() will also show protected and private properties of objects with PHP 5, on the contrary to var_dump().

Remember that print_r() will move the array pointer to the end. Use reset() to bring it back to beginning.


<pre>

<?php

    $a = array ('a' => 'apple', 'b' => 'banana', 'c' => array ('x', 'y', 'z'));

    print_r ($a);

?>

</pre>

Результат выполнения данного примера:

<pre>
Array
(
    [a] => apple
    [b] => banana
    [c] => Array
        (
            [0] => x
            [1] => y
            [2] => z
        )
)
</pre>

If you would like to capture the output of print_r(), use the return parameter. If this parameter is set to TRUE, print_r() will return its output, instead of printing it (which it does by default).

Пример 1. 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 ?>

Замечание: If you need to capture the output of print_r() with a version of PHP prior to 4.3.0, use the output-control functions.

Замечание: 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.

print_r

ohira (atto) web. de
13-Apr-2006 07:01


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('&nbsp;&nbsp;&nbsp;&nbsp;',$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

?>

sanya at hik dot hu
05-Apr-2006 07:13


I find a possibly bug, when I wanted to print the structure of a DOMDocument or a DOMDocumentType object.

print_r() outputs the object type correctly, but the properties are missing.



$doc = $imp->createDocument();

$doc->loadXML($xmlString);

print_r($doc->doctype);



the code outputs:



DOMDocumentType Object

(

)



But the subobjects of $doc->doctype exist.

reinder at fake-address dot com
31-Jan-2006 09:09


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! )

13-Dec-2005 01:00


function print_pre($var){

echo '<pre>';

print_r($var);

echo '</pre>'

}

thbley at gmail dot com
16-Nov-2005 12:10


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;

}

  

?>

jamin42b at gmail dot com
02-Sep-2005 05:52


Here's a short function that can export php arrays to javascript arrays.



<?php



function php_to_js($array, $base) {

    $js = '';

    foreach ($array as $key=>$val) {

        if (is_array($val)) {

            $js .= php_to_js($val, $base.(is_numeric($key) ? '['.$key.']' : "['".addslashes($key)."']"));

        } else {

            $js .= $base;

            $js .= is_numeric($key) ? '['.$key.']' : "['".addslashes($key)."']";

            $js .= ' = ';

            $js .= is_numeric($val) ? ''.$val.'' : "'".addslashes($val)."'";

            $js .= ";\n";

        }

    }

    return $base." = new Array();\n".$js;

}



?>



Example use:



<?php

$my_array = array('gdsag' => 4, 'hello', array(5, 6));

echo '<script>'.php_to_js($my_array).'</script>';

?>



This would output:



<script>

jsvarname = new Array();

jsvarname['gdsag'] = 4;

jsvarname[0] = 'hello';

jsvarname[1] = new Array();

jsvarname[1][0] = 5;

jsvarname[1][1] = 6;



</script>



Now the array is loaded in the browser as javascript. As you can see, it supports multidimensional arrays too.

warhog at warhog dot net
11-Aug-2005 05:01


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.

nicky dot weber at siner dot de
11-Jun-2005 02:13


Print arrays formatted for a browser easily:





<?php


function print_html_r( $aData ) {


    echo nl2br( eregi_replace( " ", " ", print_r( $data, TRUE ) ) );    


}


?>

general at NOSPAMbugfoo dot com
20-Jan-2005 01:23


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