[edit] Last updated: Fri, 10 Feb 2012

str_pad

(PHP 4 >= 4.0.1, PHP 5)

str_pad — 文字列を固定長の他の文字列で埋める

説明

string str_pad ( string $input , int $pad_length [, string $pad_string = " " [, int $pad_type = STR_PAD_RIGHT ]] )

この関数は文字列 input の左、右または両側を指定した長さで埋めます。オプションの引数 pad_string が指定されていない場合は、 input は空白で埋められ、それ以外の場合は、 pad_string からの文字で制限まで埋められます。

パラメータ

input: 入力文字列。
pad_length: pad_length の値が負、または入力文字列の長さ以下である場合、埋める操作は行われません。
pad_string: 注意:
必要とされる埋める文字数が pad_string の長さで均等に分割できない場合、pad_string は切り捨てられます。
pad_type: オプションの引数 pad_type には、 STR_PAD_RIGHT, STR_PAD_LEFT, STR_PAD_BOTH を指定可能です。 pad_typeが指定されない場合、 STR_PAD_RIGHT を仮定します。

返り値

埋めた後の文字列を返します。

例

例1 str_pad() の例


<?php
$input = "Alien";
echo str_pad($input, 10);                      // 結果は "Alien     "
echo str_pad($input, 10, "-=", STR_PAD_LEFT);  // 結果は "-=-=-Alien"
echo str_pad($input, 10, "_", STR_PAD_BOTH);   // 結果は "__Alien___"
echo str_pad($input, 6 , "___");               // 結果は "Alien_"
?>

str_repeat

str_ireplace

[edit] Last updated: Fri, 10 Feb 2012

add a note User Contributed Notes str_pad

sergey 12-Oct-2011 02:45


You can use trim functions for clearpad string:



ltrim("0001230", "0") -> 1230

rtrim("0123000", "0") -> 0123

trim("0012300")     -> 123

gene at swipesy dot com 24-Sep-2011 09:18


This is how I pad using &nbsp; :



str_replace(" ", "&nbsp;&nbsp;", str_pad($foo, 10, " ", STR_PAD_LEFT))



Seems to work well using two &nbsp; tags for each character added, at least for my use. YMMV.

goellerk at bucks dot edu 07-Jun-2010 12:43


Apparently, as of 5.3.2 the notations "STR_PAD_LEFT" and "STR_PAD_RIGHT" are case sensitive.



$yr = "10";

$yr = str_pad($yr,2,'0',str_pad_left);

print "yr = '$yr'";

yr = '  '



$yr = "10";

$yr = str_pad($yr,2,'0',STR_PAD_LEFT);

print "yr = '$yr'";

yr = '10'

hernanc 24-Apr-2009 08:45


To get Monday and Sunday's dates of the current week in Y-m-d format  do:





<?php


$mon_date = date('Y-m-d',strtotime(date('Y') . 'W' . str_pad(date('W'), 2, '0',STR_PAD_LEFT) .'1'));


$sun_date =  date('Y-m-d',strtotime(date('Y') . 'W' . str_pad(date('W'), 2, '0',STR_PAD_LEFT).'7'));


?>

Kari "Haprog" Sderholm 21-Mar-2009 06:43


Here's a quick and simple way to make an mb_str_pad function that works when you have correctly set your internal encoding.



I'm not sure how well this works in all possible scenarios but atleast it worked for me using UTF-8 as internal encoding and using this function on strings containing scandinavian characters "åäöÅÄÖ" that are double byte in UTF-8.



<?php

function mb_str_pad($input, $pad_length, $pad_string=' ', $pad_type=STR_PAD_RIGHT) {

    $diff = strlen($input) - mb_strlen($input);

    return str_pad($input, $pad_length+$diff, $pad_string, $pad_type);

}

?>

matrebatre 16-Oct-2008 11:28


Here is a simple function to convert numbers into strings like this:



0 => 0000

1 => 0001

20 => 0020

432 => 0432



<?php



function number_pad($number,$n) {

return str_pad((int) $number,$n,"0",STR_PAD_LEFT);

}



?>



$n indicates how many characters you want.

albert dot serra at camaleongroup dot com 22-Jul-2008 06:36


<?php

/** Description

   * padclear, clear a pad varchar(9) "*****HOME" -> varchar(4) "HOME"

   * _no use for INT_ : varchar(5) "00100" -> int(3) "100", use $number = (int) "00100";

   *

   * @param string, string original

   * @param char, character to replace

   * @param charreplace, final character

   * @param type, [STR_PAD_RIGHT|STR_PAD_LEFT] see str_pad

   * @return string, transformed string with charreplace

   */

  function padclear($string, $char, $charreplace = null,$type = STR_PAD_RIGHT) {



      $strlen = strlen($string) - 1;

      $i = ($type == STR_PAD_RIGHT) ? 0 : $strlen;

      $stop = ($type == STR_PAD_RIGHT) ? $strlen : 0;

      $difpos = null;

      while(is_null($difpos) && $i != $stop) {

        $difpos = ($string[$i] != $char) ? $i : null;

        if($type == STR_PAD_RIGHT) $i++;

        else $i--;

      }



      if($type == STR_PAD_RIGHT) {

        $ant = str_replace($char,$charreplace,substr($string,0,$difpos));

         $nxt = substr($string,$difpos,$strlen);

      } else {

        $ant = substr($string,0,$difpos);

        $nxt = str_replace($char,$charreplace,substr($string,$difpos,$strlen));

      }



      return $ant . $nxt;

  }



  $string = "HOME*******";

  echo padclear($string,'*','',STR_PAD_LEFT);  // HOME

  $string = "*****HOME";

  echo padclear($string,'*','',STR_PAD_RIGHT); // HOME

?>

bxi at apparoat dot nl 20-Mar-2008 06:17


In case you want to pad 2 strings together with a character you can use:



<?php

function pad_between_strings($string1, $string2, $length, $char = " ") {

    $fill_length = $length - ( strlen($string1) + strlen($string2) );

    return $string1 . str_repeat($char, $fill_length) . $string2;

}

?>

Spudley 18-Jul-2007 08:47


Warning: If your string includes non-ascii characters (eg the British pounds sign), str_pad() will treat these as two characters when calculating the padding.



So for example:

<?php

str_pad($currency_symbol.$showtottopay,12," ",STR_PAD_LEFT);

?>

will produce a different length string depending on whether $currency_symbol is pounds or dollars.



Hope this helps someone -- it caused me a lot of problems with misaligned columns in my invoices until I worked it out.

christian dot reinecke at web dot de 01-Apr-2007 10:43


Fills the first argument (mostly a number, f.e. from a <select> loop to display a date or time) with zeroes.



<?php

function zerofill($mStretch, $iLength = 2)

{

    $sPrintfString = '%0' . (int)$iLength . 's';

    return sprintf($sPrintfString, $mStretch);

}

?>



sprintf() is indeed faster than str_pad.

Charles 05-Dec-2006 03:53


More corrections to the original flap / Tomek Krzeminski code below (well someone has to check it!) -- the code is a bit mangled but it is still the same:



<?php



function mb_str_pad($ps_input, $pn_pad_length, $ps_pad_string = " ", $pn_pad_type = STR_PAD_RIGHT, $ps_encoding = NULL) {

  $ret = "";



  if (is_null($ps_encoding))

    $ps_encoding = mb_internal_encoding();



  $hn_length_of_padding = $pn_pad_length - mb_strlen($ps_input, $ps_encoding);

  $hn_psLength = mb_strlen($ps_pad_string, $ps_encoding); // pad string length

   

  if ($hn_psLength <= 0 || $hn_length_of_padding <= 0) {

    // Padding string equal to 0:

    //

    $ret = $ps_input;

    }

  else {

    $hn_repeatCount = floor($hn_length_of_padding / $hn_psLength); // how many times repeat



    if ($pn_pad_type == STR_PAD_BOTH) {

      $hs_lastStrLeft = "";

      $hs_lastStrRight = "";

      $hn_repeatCountLeft = $hn_repeatCountRight = ($hn_repeatCount - $hn_repeatCount % 2) / 2;



      $hs_lastStrLength = $hn_length_of_padding - 2 * $hn_repeatCountLeft * $hn_psLength; // the rest length to pad

      $hs_lastStrLeftLength = $hs_lastStrRightLength = floor($hs_lastStrLength / 2);      // the rest length divide to 2 parts

      $hs_lastStrRightLength += $hs_lastStrLength % 2; // the last char add to right side



      $hs_lastStrLeft = mb_substr($ps_pad_string, 0, $hs_lastStrLeftLength, $ps_encoding);

      $hs_lastStrRight = mb_substr($ps_pad_string, 0, $hs_lastStrRightLength, $ps_encoding);



      $ret = str_repeat($ps_pad_string, $hn_repeatCountLeft) . $hs_lastStrLeft;

      $ret .= $ps_input;

      $ret .= str_repeat($ps_pad_string, $hn_repeatCountRight) . $hs_lastStrRight;

      }

    else {

      $hs_lastStr = mb_substr($ps_pad_string, 0, $hn_length_of_padding % $hn_psLength, $ps_encoding); // last part of pad string



      if ($pn_pad_type == STR_PAD_LEFT)

        $ret = str_repeat($ps_pad_string, $hn_repeatCount) . $hs_lastStr . $ps_input;

      else

        $ret = $ps_input . str_repeat($ps_pad_string, $hn_repeatCount) . $hs_lastStr;

      }

    }



  return $ret;

  }



?>

rafaeljaquestudojunto at gmail dot com 11-Sep-2006 05:43


Looking forward to make some dynamic tabulation, i've noticed that the output appeared twice. I suppose that the parser recognize \t, \n and any other special character as a single character...



So.. If you need 4 tabulatins, just make...



<?php



print str_pad('',4,"\t");



?>

Silvio Ginter (silvio dot ginter at gmx dot de) 15-Nov-2005 08:43


Hello,





for anyone who needs this, I wrote this extension to str_pad. For details, just look at the comments.





<?php





$string = 'this is a test';


$oldLen = strlen($string);


$direction = STR_PAD_BOTH;


echo $string.'<br>';


echo str_const_len($string, 101, '#', $direction).'<br>';


echo $string.'<br>';


echo str_const_len($string, $oldLen, '#', $direction).'<br>';


echo $string.'<br><br>'."\n";





    


    


/*     This function is an extension to str_pad, it manipulates the referenced


    string '$str' and stretches or reduces it to the specified length. It


    returns the number of characters, that were added or stripped. */


function str_const_len(&$str, $len, $char = ' ', $str_pad_const = STR_PAD_RIGHT) {


    $origLen = strlen($str);


    if (strlen($str) < $len) {     /* stretch string */


        $str = str_pad($str, $len, $char, $str_pad_const);


    }


    else {                         /* reduce string */


        switch ($str_pad_const) {


            case STR_PAD_LEFT:


                $str = substr($str, (strlen($str) - $len), $len);


                break;


            case STR_PAD_BOTH:


                $shorten = (int) ((strlen($str) - $len) / 2);


                $str = substr($str, $shorten, $len);


                break;


            default:


                $str = substr($str, 0, $len);


                break;


        }


    }


    return ($len - $origLen);


}


?>

private dot email at optusnet dot com dot au 10-Aug-2005 05:04


I wrote these 3 functions that live in a library i include in every programme. I find them useful, and the syntax is easy.



<?php



$str = "test";



function str_pad_right ( $string , $padchar , $int ) {

    $i = strlen ( $string ) + $int;

    $str = str_pad ( $string , $i , $padchar , STR_PAD_RIGHT );

    return $str;

}

    

function str_pad_left ( $string , $padchar , $int ) {

    $i = strlen ( $string ) + $int;

    $str = str_pad ( $string , $i , $padchar , STR_PAD_LEFT );

    return $str;

}

    

function str_pad_both ( $string , $padchar , $int ) {

    $i = strlen ( $string ) + ( $int * 2 );

    $str = str_pad ( $string , $i , $padchar , STR_PAD_BOTH );

    return $str;

}



echo str_pad_left ( $str , "-" , 3 ); // Produces: ---test

echo str_pad_right ( $str , "-" , 3 ); // Produces: test---

echo str_pad_both ( $str , "-" , 3 ); // Produces: ---test---

?>



Hope this can help someone!

zubfatal <root at it dot dk> 27-Mar-2005 09:28


<?php

    /**

     * str_pad_html - Pad a string to a certain length with another string.

     * accepts HTML code in param: $strPadString.

     * 

     * @name        str_pad_html()

     * @author        Tim Johannessen <root@it.dk>

     * @version        1.0.0

     * @param        string    $strInput    The array to iterate through, all non-numeric values will be skipped.

     * @param        int    $intPadLength    Padding length, must be greater than zero.

     * @param        string    [$strPadString]    String to pad $strInput with (default: &nbsp;)

     * @param        int        [$intPadType]        STR_PAD_LEFT, STR_PAD_RIGHT (default), STR_PAD_BOTH

     * @return        string    Returns the padded string

    **/

    function str_pad_html($strInput = "", $intPadLength, $strPadString = "&nbsp;", $intPadType = STR_PAD_RIGHT) {

        if (strlen(trim(strip_tags($strInput))) < intval($intPadLength)) {

            

            switch ($intPadType) {

                 // STR_PAD_LEFT

                case 0:

                    $offsetLeft = intval($intPadLength - strlen(trim(strip_tags($strInput))));

                    $offsetRight = 0;

                    break;

                    

                // STR_PAD_RIGHT

                case 1:

                    $offsetLeft = 0;

                    $offsetRight = intval($intPadLength - strlen(trim(strip_tags($strInput))));

                    break;

                    

                // STR_PAD_BOTH

                case 2:

                    $offsetLeft = intval(($intPadLength - strlen(trim(strip_tags($strInput)))) / 2);

                    $offsetRight = round(($intPadLength - strlen(trim(strip_tags($strInput)))) / 2, 0);

                    break;

                    

                // STR_PAD_RIGHT

                default:

                    $offsetLeft = 0;

                    $offsetRight = intval($intPadLength - strlen(trim(strip_tags($strInput))));

                    break;

            }

            

            $strPadded = str_repeat($strPadString, $offsetLeft) . $strInput . str_repeat($strPadString, $offsetRight);

            unset($strInput, $offsetLeft, $offsetRight);

            

            return $strPadded;

        }

        

        else {

            return $strInput;

        }

    }



?>

tacomage at NOSPAM dot devilishly-deviant dot net 07-Jul-2004 08:04


If you want to pad a string to a certain screen length with &nbsp; or other HTML entities, but don't want to risk messing up any HTML characters inside the string, try this:





<?php


function str_pad_as_single($input, $len, $pad, $flag=STR_PAD_RIGHT)


{


  $trans=array('$'=>$input,' '=>$pad);


  $output=str_pad('$',$len-strlen($input)+1,' ',$flag);


  $output=strtr($output,$trans);


  return $output;


}


echo str_pad_as_single('<img src="some.gif">',22,'&nbsp;');


// will output <img src="some.gif">&nbsp;&nbsp;





echo str_pad_as_single('<img src="some.gif">',22,'&nbsp;',STR_PAD_BOTH);


// will output &nbsp;<img src="some.gif">&nbsp;





echo str_pad_as_single('<img src="some.gif">',22,'&nbsp;',STR_PAD_LEFT);


// will output &nbsp;&nbsp;<img src="some.gif">


?>





It works by using single characters for str_pad, then replacing the characters with the full strings using strtr, so the two strings can't interfere with each other.  It also conveniently has the same syntax as str_pad.  Yes, I realize that spacing an image with text isn't the best idea, but it's just an example, it'll apply to other HTML as well :-P

giorgio dot balestrieri at mail dot wind dot it 09-Mar-2004 08:49


For number formatting (like writing numbers with leading zeroes etc.) , sprintf is much faster than str_pad.


Consider the following snippet (it take some minutes to run):





<?php


  echo "str_pad test started, please wait...\n";


  


  $intStart = time();


  for ($idx = 1; $idx <= 10000000; $idx++)


    $strFoo = str_pad($idx, 10, "0", STR_PAD_LEFT);


  $intEnd = time();


  


  echo "str_pad cycle completed in " . ($intEnd - $intStart) . " seconds\n";


  echo "sprintf test started, please wait...\n";  


  


  $intStart = time();


  for ($idx = 1; $idx <= 10000000; $idx++)


    $strFoo = sprintf("%010d", $idx);


  $intEnd = time();


  


  echo "sprintf cycle completed in " . ($intEnd - $intStart) . " seconds\n";


?>





The str_pad cyle runs 80-100% slower on my pc...

bob [at] bobarmadillo [dot] com 03-Dec-2002 09:22


In a lot of cases you're better off using str_repeat if you want to use something like   - it repeats the entire string.





Using str_repeat, I wrote a full string pad function that should closely mimic str_pad in every other way:





<?php


function full_str_pad($input, $pad_length, $pad_string = '', $pad_type = 0) {


 $str = '';


 $length = $pad_length - strlen($input);


 if ($length > 0) { // str_repeat doesn't like negatives


  if ($pad_type == STR_PAD_RIGHT) { // STR_PAD_RIGHT == 1


   $str = $input.str_repeat($pad_string, $length);


  } elseif ($pad_type == STR_PAD_BOTH) { // STR_PAD_BOTH == 2


   $str = str_repeat($pad_string, floor($length/2));


   $str .= $input;


   $str .= str_repeat($pad_string, ceil($length/2));


  } else { // defaults to STR_PAD_LEFT == 0


   $str = str_repeat($pad_string, $length).$input;


  }


 } else { // if $length is negative or zero we don't need to do anything


  $str = $input;


 }


 return $str;


}





$pad_me = "Test String";


echo '|'.full_str_pad($pad_me, 20, ' ')."|\n";


echo '|'.full_str_pad($pad_me, 20, ' ', STR_PAD_RIGHT)."|\n";


echo '|'.full_str_pad($pad_me, 20, ' ', STR_PAD_BOTH)."|\n";


?>

david dot rensonnet at swing dot be 02-Dec-2002 03:18


my solution to saveloywill at netscape dot net:



$myvar2="Alien";

$myvar=str_pad($myvar2,15," ",STR_PAD_RIGHT);

$myvar=str_replace(" ","&nbsp;",$myvar);



this way, only complete spaces will show up.



enjoy!

david rensonnet

Fahad dot Gilani at anu dot edu dot au 02-Dec-2002 02:22


Basically, *all* of you guys have a 'long' way of padding text with html tags (which includes &nbsp;) You dont even have to do a str_replace... try the following code and this will work with ANY html tag there is out there and you don't have to worry about tag character lengths so on and so forth:

<?

  $text = "This is pretty interesting!";

  $pad_string = "&nbsp;";

  

  //Pad text on both sides 

  $text = str_pad($text, strlen($text)+(20*strlen($pad_string)), $pad_string, STR_PAD_BOTH);

  print $text." Dont you think?";

?>

Will produce:

          This is pretty interesting!           Dont you think?



Cheers,

Fahad

no dot spam at no dot spam dot no 26-Sep-2002 04:28


there could already be spaces in the string.



1) strlen the string

2) replace spaces with "AUniqueString"

3) strlen the new string

4) compare the two strlen's

5) pad as needed considering the new strlen

6) finally, replace all "AUniqueString" 's with &nbsp; 's



hack & a half, slow as well i bet

cd579 at hotmail dot com 22-Aug-2002 01:53


Why not just use a space[' '] instead of a character that COULD be inside the string, and risk messing it up?  Example:



$string = 'test';



$string = str_pad($string, 10, " ", STR_PAD_BOTH);

// $string now equals '      test' 



$string = str_replace(" ", "&nbsp;", $string);

mreilly at NOSPAM dot mac dot com 20-Aug-2002 11:23


When provided with a string of characters as the pad value, str_pad uses all the characters as fill, and can leave partial strings. (eg. If the pad value is 'ABC' and it needs 5 characters to pad with, it outputs 'ABCAB'.) This is a problem when you want to pad with non-breaking spaces, the code for which is 6 characters long. 



This can be resolved by first padding the string with a single character that won't be found in the strings such as * then doing a str_replace of * with &nbsp;.

saveloywill at netscape dot net 10-Aug-2002 12:50


Here is my solution to the above problem.

Simply place the code in question inbetween  html <pre> tags, like this:



<?php

print "<pre>";

$input = "Alien";

print str_pad($input, 10);

print "*";

print "</pre>";

?>



Thanks.

pozytron#mac#com 08-Jul-2002 02:20


The trouble with cj@NOSPAM.ceejayoz.com's version over pestilenc@hotmail.com's is that many of the times it is used, it will end up with fragments of the "&nbsp;" code.



For example, the following code:

<?php

echo str_pad("TESTSTRING",60,"&nbsp;",STR_PAD_BOTH);

?>



produces the following HTML output:

&nbsp;&nbsp;&nbsp;&nbsp;&TESTSTRING&nbsp;&nbsp;&nbsp;&nbsp;&

cj at NOSPAM dot ceejayoz dot com 17-Jun-2002 12:38


Another solution to no_email@php.net's problem would be to simply multiply the padding string by 6.



e.g.



$string = str_pad($string, 10, "&nbsp;", STR_PAD_BOTH);



becomes



$string = str_pad($string, 60, "&nbsp;", STR_PAD_BOTH);



which will avoid problems with the above solution, which will mess up text that has the * in it (or whichever character you're replacing)

pestilenc at hotmail dot com 06-Jun-2002 04:26


For me this worked.

$string = 'help';



#First, str_pad() with unique character.

$string = str_pad($string, 10, "*", STR_PAD_BOTH);

#$string = '***help***';



#Second, str_replace with '&nbsp;'

$string = str_replace("*", "&nbsp;", $string);

no_email at php dot net 30-May-2002 10:34


To convert your string couldnt you just use strval($var)?



What if you want non-breaking spaces? If I try to str_pad with "&nbsp;" PHP thinks my padding string is 6 characters, whn in HTML it is only one.

jared at dctkc dot com 03-May-2002 04:25


matthew.somerville's code did NOT work for me.

neither did bert@catsburg.com's.

neither did any other documentation.

(if I isolated the code by itself, they all worked; but in the context I was using it, $value was numeric, and there is NO WAY to force it to be a string in PHP).



I had to roll my own. I used 'trim' to _force_

the value of $value to be string, because as

long as PHP thought it was numeric, I could

not use any form of left-padding with zeros.



This worked (I use sprintf to left-pad

$value with zeros to a length of 4):



sprintf("%04s",trim($value));

matthew dot somerville at trinity dot oxford dot ac dot uk 05-Aug-2001 06:53


I find:





$mystr = substr("0000$mystr",-4)





(where the 0s are padding characters and -4 is the negative of the maxlength to pad to) is even simpler.

add a note