PHP 7.0.6 Released

str_pad

(PHP 4 >= 4.0.1, PHP 5, PHP 7)

str_padPad a string to a certain length with another string

Description

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

This functions returns the input string padded on the left, the right, or both sides to the specified padding length. If the optional argument pad_string is not supplied, the input is padded with spaces, otherwise it is padded with characters from pad_string up to the limit.

Parameters

input

The input string.

pad_length

If the value of pad_length is negative, less than, or equal to the length of the input string, no padding takes place, and input will be returned.

pad_string

Note:

The pad_string may be truncated if the required number of padding characters can't be evenly divided by the pad_string's length.

pad_type

Optional argument pad_type can be STR_PAD_RIGHT, STR_PAD_LEFT, or STR_PAD_BOTH. If pad_type is not specified it is assumed to be STR_PAD_RIGHT.

Return Values

Returns the padded string.

Examples

Example #1 str_pad() example

<?php
$input 
"Alien";
echo 
str_pad($input10);                      // produces "Alien     "
echo str_pad($input10"-="STR_PAD_LEFT);  // produces "-=-=-Alien"
echo str_pad($input10"_"STR_PAD_BOTH);   // produces "__Alien___"
echo str_pad($input,  6"___");               // produces "Alien_"
echo str_pad($input,  3"*");                 // produces "Alien"
?>

User Contributed Notes

Marjune
1 year ago
since the default pad_type is STR_PAD_RIGHT. using STR_PAD_BOTH were always favor in the right pad if the required number of padding characters can't be evenly divided.

e.g

<?php

echo str_pad("input", 10, "pp", STR_PAD_BOTH ); // ppinputppp
echo str_pad("input", 6, "p", STR_PAD_BOTH ); // inputp
echo str_pad("input", 8, "p", STR_PAD_BOTH ); //pinputpp

?>
wes at nospamplsexample dot org
1 year ago
multibyte version:

<?php
function mb_str_pad($str, $pad_len, $pad_str = ' ', $dir = STR_PAD_RIGHT, $encoding = NULL)
{
   
$encoding = $encoding === NULL ? mb_internal_encoding() : $encoding;
   
$padBefore = $dir === STR_PAD_BOTH || $dir === STR_PAD_LEFT;
   
$padAfter = $dir === STR_PAD_BOTH || $dir === STR_PAD_RIGHT;
   
$pad_len -= mb_strlen($str, $encoding);
   
$targetLen = $padBefore && $padAfter ? $pad_len / 2 : $pad_len;
   
$strToRepeatLen = mb_strlen($pad_str, $encoding);
   
$repeatTimes = ceil($targetLen / $strToRepeatLen);
   
$repeatedString = str_repeat($pad_str, max(0, $repeatTimes)); // safe if used with valid utf-8 strings
   
$before = $padBefore ? mb_substr($repeatedString, 0, floor($targetLen), $encoding) : '';
   
$after = $padAfter ? mb_substr($repeatedString, 0, ceil($targetLen), $encoding) : '';
    return
$before . $str . $after;
}
?>
qeremy [atta] gmail [dotta] com
3 years ago
A proper unicode string padder;

<?php
mb_internal_encoding
('utf-8'); // @important

function str_pad_unicode($str, $pad_len, $pad_str = ' ', $dir = STR_PAD_RIGHT) {
   
$str_len = mb_strlen($str);
   
$pad_str_len = mb_strlen($pad_str);
    if (!
$str_len && ($dir == STR_PAD_RIGHT || $dir == STR_PAD_LEFT)) {
       
$str_len = 1; // @debug
   
}
    if (!
$pad_len || !$pad_str_len || $pad_len <= $str_len) {
        return
$str;
    }
   
   
$result = null;
   
$repeat = ceil($str_len - $pad_str_len + $pad_len);
    if (
$dir == STR_PAD_RIGHT) {
       
$result = $str . str_repeat($pad_str, $repeat);
       
$result = mb_substr($result, 0, $pad_len);
    } else if (
$dir == STR_PAD_LEFT) {
       
$result = str_repeat($pad_str, $repeat) . $str;
       
$result = mb_substr($result, -$pad_len);
    } else if (
$dir == STR_PAD_BOTH) {
       
$length = ($pad_len - $str_len) / 2;
       
$repeat = ceil($length / $pad_str_len);
       
$result = mb_substr(str_repeat($pad_str, $repeat), 0, floor($length))
                    .
$str
                      
. mb_substr(str_repeat($pad_str, $repeat), 0, ceil($length));
    }
   
    return
$result;
}
?>

Test;
<?php
// needs ie. "test.php" file encoded in "utf-8 without bom"
$s = '...';
for (
$i = 3; $i <= 1000; $i++) {
   
$s1 = str_pad($s, $i, 'AO', STR_PAD_BOTH); // can not inculde unicode char!!!
   
$s2 = str_pad_unicode($s, $i, 'ÄÖ', STR_PAD_BOTH);
   
$sl1 = strlen($s1);
   
$sl2 = mb_strlen($s2);
    echo 
"len $sl1: $s1 \n";
    echo 
"len $sl2: $s2 \n";
    echo 
"\n";
    if (
$sl1 != $sl2) die("Fail!");
}
?>

Output;
len 3: ...
len 3: ...

len 4: ...A
len 4: ...Ä

len 5: A...A
len 5: Ä...Ä

len 6: A...AO
len 6: Ä...ÄÖ
...
pestilenc at hotmail dot com
13 years ago
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);
mcinp
1 year ago
a different, more robust multibyte version of str_pad that works correctly only if $pad_string is non-multibyte string

function my_mb_str_pad($input, $pad_length, $pad_string=' ', $pad_type=STR_PAD_RIGHT,$encoding='UTF-8'){
    $mb_diff=mb_strlen($str, $encoding)-strlen($string);       
    return str_pad($input,$pad_length+$mb_diff,$pad_string,$pad_type);
}
christian dot reinecke at web dot de
9 years ago
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.
Fahad dot Gilani at anu dot edu dot au
13 years ago
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
Silvio Ginter (silvio dot ginter at gmx dot de)
10 years ago
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);
}
?>
zubfatal <root at it dot dk>
11 years ago
<?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;
        }
    }

?>
bxi at apparoat dot nl
8 years ago
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;
}
?>
private dot email at optusnet dot com dot au
10 years ago
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!
gene at swipesy dot com
4 years ago
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.
Anonymous
1 month ago
Here is the mcinp's version of mb_str_pad bugfixed:

<?php
function mb_str_pad($input, $pad_length, $pad_string=' ', $pad_type=STR_PAD_RIGHT,$encoding='UTF-8'){
       
$mb_diff=mb_strlen($input, $encoding)-strlen($input);
        return
str_pad($input,$pad_length-$mb_diff,$pad_string,$pad_type);
    }
?>

Still working correctly only if $pad_string is non-multibyte string
Kari &#34;Haprog&#34; Sderholm
7 years ago
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);
}
?>
Spudley
8 years ago
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.
Anonymous
9 months ago
For simple padding, you can use sprintf, which is faster:
see http://php.net/sprintf Example #5 "Specifying padding character"
bob [at] bobarmadillo [dot] com
13 years ago
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";
?>
matrebatre
7 years ago
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.
sergey
4 years ago
You can use trim functions for clearpad string:

ltrim("0001230", "0") -> 1230
rtrim("0123000", "0") -> 0123
trim("0012300")     -> 123
mreilly at NOSPAM dot mac dot com
13 years ago
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;.
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