str_pad

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

str_pad문자열을 지정한 길이가 되도록 다른 문자열로 채웁니다

설명

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

지정한 길이가 되도록 왼쪽, 오른쪽, 혹은 양쪽 모두를 채워넣은 input 문자열을 반환합니다. 선택적인 인수 pad_string를 제공하지 않으면, input을 공백으로 채웁니다. 그렇지 않으면, pad_string의 문자들로 제한까지 채워넣습니다.

인수

input

입력 문자열.

pad_length

pad_length가 음수이거나 입력 문자열의 길이보다 작으면, 채우기를 하지 않습니다.

pad_string

Note:

pad_string의 길이가 채울 문자 수로 정확히 나누어 지지 않을 경우, pad_string을 중간에 자릅니다.

pad_type

선택적인 인수 pad_typeSTR_PAD_RIGHT, STR_PAD_LEFT, STR_PAD_BOTH를 사용할 수 있습니다. pad_type를 지정하지 않으면 STR_PAD_RIGHT를 사용합니다.

반환값

채운 문자열을 반환합니다.

예제

Example #1 str_pad() 예제

<?php
$input 
"Alien";
echo 
str_pad($input10);                      // "Alien     "을 생성.
echo str_pad($input10"-="STR_PAD_LEFT);  // "-=-=-Alien"을 생성.
echo str_pad($input10"_"STR_PAD_BOTH);   // "__Alien___"을 생성.
echo str_pad($input"___");               // "Alien_"을 생성.
?>

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User Contributed Notes 23 notes

up
58
Marjune
5 years 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

?>
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14
qeremy [atta] gmail [dotta] com
6 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
...
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9
pestilenc at hotmail dot com
17 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);
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12
wes at nospamplsexample dot org
5 years 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;
}
?>
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1
Kirill Fuchs
2 years ago
sprintf() is not always faster... It certainly scales a lot better then str_pad so when running a benchmark that pads 10k characters,  sprintf will come out on top. But if you benchmarked a more real world scenario, it seems str_pad comes out the clear winner.

$sTime = microtime(true);
$count = 5;
$s = sprintf("%'\n5s", "\n");
$eTime = microtime(true);
echo 'sprintf ran in ' . (($eTime - $sTime) * 1000) . ' milliseconds' . "\n";

$sTime = microtime(true);
$s = str_pad("\n", 5, "\n");
$eTime = microtime(true);
echo 'str_pad ran in ' . (($eTime - $sTime) * 1000) . ' milliseconds' . "\n";

sprintf ran in 0.015974044799805 milliseconds
str_pad ran in 0.0059604644775391 milliseconds
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1
Anonymous
3 years 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
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4
christian dot reinecke at web dot de
12 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.
up
2
mcinp
4 years 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);
}
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2
Spudley
12 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.
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2
bxi at apparoat dot nl
11 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;
}
?>
up
0
gene at swipesy dot com
8 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.
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0
zubfatal <root at it dot dk>
14 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;
        }
    }

?>
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0
bob [at] bobarmadillo [dot] com
17 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";
?>
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0
Fahad dot Gilani at anu dot edu dot au
17 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
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-1
private dot email at optusnet dot com dot au
14 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!
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-1
Silvio Ginter (silvio dot ginter at gmx dot de)
14 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);
}
?>
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-4
matrebatre
11 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.
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-2
Kari &#34;Haprog&#34; Sderholm
10 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);
}
?>
up
-1
gtwizard
2 years ago
sprintf is faster

$sTime = microtime(true);
$s = sprintf("%'-1000000s", '-');
$eTime = microtime(true);
echo 'sprintf ran in ' . (($eTime - $sTime) * 1000) . ' milliseconds' . "\n";

$sTime = microtime(true);
$s = str_pad('-', 1000000, '-');
$eTime = microtime(true);
echo 'str_pad ran in ' . (($eTime - $sTime) * 1000) . ' milliseconds' . "\n";

//result
sprintf ran in 2.0260810852051 milliseconds
str_pad ran in 26.59797668457 milliseconds
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-1
Anonymous
4 years ago
For simple padding, you can use sprintf, which is faster:
see http://php.net/sprintf Example #5 "Specifying padding character"
up
-3
mreilly at NOSPAM dot mac dot com
17 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;.
up
-12
sergey
8 years ago
You can use trim functions for clearpad string:

ltrim("0001230", "0") -> 1230
rtrim("0123000", "0") -> 0123
trim("0012300")     -> 123
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-3
pulketo at gmail dot com
2 years ago
// Columnizer: add padding into text columns according maximum column size.
// sample input:
$a='[1515] -> ID=1515 / post_date=2012-06-18 04:48:47 / post_name=review-terminatrix-by-sfam
    [177] -> ID=177 / post_date=2017-05-12 12:12:03 / post_name=review-the-terminator-by-sfam
    [228621100] -> ID=2286 / post_date=2012-06-18 04:48:32 / post_name=terminator-3-rise-of-the-machines-2003';

function columnize($input, $separator=" "){
    $lines = explode("\n", $input);
    foreach ($lines as $k=>$line){
      $r[$k] = explode(" ", trim($line));
    }
    // print_r($r);
    $nc = sizeOf($r[0]);
    // echo $nc;
    for($i=0;$i<$nc;$i++){
      $col[$i] = array_column($r, $i);
      }
    // print_r($col);
    for ($i=0;$i<sizeof($col);$i++){
      $maxlen = max(array_map('strlen', $col[$i]));
      $tam[$i]=$maxlen;
      // echo "$i:$maxlen".PHP_EOL;
      $cs[$i]=$maxlen;
    }
    // print_r($cs);
    $o="";
    for ($r=0;$r<sizeOf($lines);$r++){
      for ($c=0;$c<sizeof($cs);$c++){
        $o.= str_pad($col[$c][$r], $cs[$c]+2, " ", STR_PAD_RIGHT );
      }
      $o .= PHP_EOL;
    }   
    return $o;
  }

echo $columnize($a);
// will output text nicely in columns :)
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