(PHP 4 >= 4.0.1, PHP 5, PHP 7)
str_pad — Pad a string to a certain length with another 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.
inputThe 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_stringNote:
The
pad_stringmay be truncated if the required number of padding characters can't be evenly divided by thepad_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.
Returns the padded string.
Example #1 str_pad() example
<?php
$input = "Alien";
echo str_pad($input, 10); // produces "Alien "
echo str_pad($input, 10, "-=", STR_PAD_LEFT); // produces "-=-=-Alien"
echo str_pad($input, 10, "_", STR_PAD_BOTH); // produces "__Alien___"
echo str_pad($input, 6, "___"); // produces "Alien_"
echo str_pad($input, 3, "*"); // produces "Alien"
?>
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
?>
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 . $after;
}
?>
A proper unicode string padder;
<?php
mb_internal_encoding('utf-8'); // @important
function str_pad_unicode($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
...
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 ' '
$string = str_replace("*", " ", $string);
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,$pad_type);
}
Fills the first argument (mostly a number, f.e. from a <select> loop to display a date or time) with zeroes.
<?php
function zerofill($mStretch, $iLength = 2)
{
$sPrintfString = '%0' . (int)$iLength . 's';
return sprintf($sPrintfString, $mStretch);
}
?>
sprintf() is indeed faster than str_pad.
Basically, *all* of you guys have a 'long' way of padding text with html tags (which includes ) 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 = " ";
//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
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);
}
?>
<?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 $strInput with (default: )
* @param int [$intPadType] STR_PAD_LEFT, STR_PAD_RIGHT (default), STR_PAD_BOTH
* @return string Returns the padded string
**/
function str_pad_html($strInput = "", $intPadLength, $strPadString = " ", $intPadType = STR_PAD_RIGHT) {
if (strlen(trim(strip_tags($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 $strInput;
}
}
?>
In case you want to pad 2 strings together with a character you can use:
<?php
function pad_between_strings($string1, $string2, $length, $char = " ") {
$fill_length = $length - ( strlen($string1) + strlen($string2) );
return $string1 . str_repeat($char, $fill_length) . $string2;
}
?>
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 ( $str , "-" , 3 ); // Produces: ---test---
?>
Hope this can help someone!
This is how I pad using :
str_replace(" ", " ", str_pad($foo, 10, " ", STR_PAD_LEFT))
Seems to work well using two tags for each character added, at least for my use. YMMV.
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 $pad_string is non-multibyte string
Here's a quick and simple way to make an mb_str_pad function that works when you have correctly set your internal encoding.
I'm not sure how well this works in all possible scenarios but atleast it worked for me using UTF-8 as internal encoding and using this function on strings containing scandinavian characters "åäöÅÄÖ" that are double byte in UTF-8.
<?php
function mb_str_pad($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, $pad_type);
}
?>
Warning: If your string includes non-ascii characters (eg the British pounds sign), str_pad() will treat these as two characters when calculating the padding.
So for example:
<?php
str_pad($currency_symbol.$showtottopay,12," ",STR_PAD_LEFT);
?>
will produce a different length string depending on whether $currency_symbol is pounds or dollars.
Hope this helps someone -- it caused me a lot of problems with misaligned columns in my invoices until I worked it out.
For simple padding, you can use sprintf, which is faster:
see http://php.net/sprintf Example #5 "Specifying padding character"
In a lot of cases you're better off using str_repeat if you want to use something like - it repeats the entire string.
Using str_repeat, I wrote a full string pad function that should closely mimic str_pad in every other way:
<?php
function full_str_pad($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";
?>
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.
You can use trim functions for clearpad string:
ltrim("0001230", "0") -> 1230
rtrim("0123000", "0") -> 0123
trim("0012300") -> 123
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 .
