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Last updated: Sat, 27 Jan 2007

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# substr_replace

(PHP 4, PHP 5)

substr_replace -- Заменяет часть строки

## Описание

string substr_replace ( string string, string replacement, int start [, int length] )

substr_replace() заменяет часть строки `string` начинающуюся с символа с порядковым номером `start` и длиной `length` строкой `replacement` и возвращает результат.

Если `start` - положительное число, замена начинается с символа с порядковым номером `start`.

Если `start` - отрицательное число, замена начинается с символа с порядковым номером `start`, считая от конца строки.

Если аргумент `length` - положительное число, то он определяет длину заменяемой подстроки. Если этот аргумент отрицательный, он определяет количество символов от конца строки, на котором заканчивается замена. Этот аргумент необязателен и по умолчанию равен strlen(`string` );, т.е. замена до конца строки `string`.

Пример 1. Пример использования substr_replace()

`<?php
$var = 'ABCDEFGH:/MNRPQR/';
echo "Оригинал: $var<hr />\n";
/* Обе следующих строки заменяют всю строку $var на 'bob'. */
echo substr_replace($var, 'bob', 0) . "<br />\n";
echo substr_replace($var, 'bob', 0, strlen($var)) . "<br />\n";
/* Вставляет 'bob' в начало $var. */
echo substr_replace($var, 'bob', 0, 0) . "<br />\n";
/* Обе следующих строки заменяют 'MNRPQR' in $var на 'bob'. */
echo substr_replace($var, 'bob', 10, -1) . "<br />\n";
echo substr_replace($var, 'bob', -7, -1) . "<br />\n";
/* Удаляет 'MNRPQR' из $var. */
echo substr_replace($var, '', 10, -1) . "<br />\n";
?>`

> Замечание: Эта функция безопасна для обработки данных в двоичной форме.

См. также описание функций str_replace() и substr().

add a note User Contributed Notes
substr_replace
chuayw2000 at hotmail dot com
09-Dec-2005 03:33
`I don't know if this function is multibyte safe but I've written a function that will do the same in multibyte mode.
<?php
//Check to see if it exists in case PHP has this function later
if (!function_exists("mb_substr_replace")){
//Same parameters as substr_replace with the extra encoding parameter.
function mb_substr_replace($string,$replacement,$start,$length=null,$encoding = null){
if ($encoding == null){
if ($length == null){
return mb_substr($string,0,$start).$replacement;
}
else{
return mb_substr($string,0,$start).$replacement.mb_substr($string,$start + $length);
}
}
else{
if ($length == null){
return mb_substr($string,0,$start,$encoding).$replacement;
}
else{
return mb_substr($string,0,$start,$encoding). $replacement. mb_substr($string,$start + $length,mb_strlen($string,$encoding),$encoding);
}
}
}
}
?>`
michael(at)webstaa(dot)com
05-Dec-2005 08:47
`I created this because of the need to mask a credit-card number like **** **** **** 8862
string mask ( string str, int start [, int length] )
mask() masks a copy of str delimited by the start and (optionally) length parameters with asterisks (*) in place of non-whitespace characters
<?php
function mask ( $str, $start = 0, $length = null ) {
$mask = preg_replace ( "/\S/", "*", $str );
if ( is_null ( $length )) {
$mask = substr ( $mask, $start );
$str = substr_replace ( $str, $mask, $start );
} else {
$mask = substr ( $mask, $start, $length );
$str = substr_replace ( $str, $mask, $start, $length );
}
return $str;
}
?>`
hermes at andycostell dot com
27-Aug-2005 11:48
`I suggest changing the function suggested by Guru Evi slightly. I found that it doesn't work as written here.
Original:
function add_3dots($string,$repl,$start,$limit) {
if(strlen($string) > $limit) {
return substr_replace(strip_tags($string),$repl,$start,$limit);
} else {
return $string;
};
};
I suggest:
function add_3dots($string,$repl,$limit) {
if(strlen($string) > $limit) {
return substr_replace(strip_tags($string),$repl,$limit-strlen($repl));
} else {
return $string;
}
}
Usage:
$max_length=10;//the max number of characters you want to display
$too_long_string="BLAH BLAH BLAH BLAH BLAH etc.";//the string you want to shorten (if it's longer than the $limit)
$shorter_string=add_3_dots($too_long_string,"...",$max_length);`
Guru Evi
13-Jul-2005 12:44
`If your string is not long enough to meet what you specify in start and length then the replacement string is added towards the end of the string.
I wanted to replace the end of the string with ... if the string was too long to display (for instance article preview on a website). The problem was that my string was sometimes not that long and it still added the replacement string. So I wrote a function to replace substr_replace in my website:
function add_3dots($string,$repl,$start,$limit) {
if(strlen($string) > $limit) {
return substr_replace(strip_tags($string),$repl,$start,$limit);
} else {
return $string;
};
};
I use strip_tags to strip out the HTML otherwise you might get a screwed up HTML (when a tags open in the string, but because you cut-off it doesn't)`
ogt at parasane dot com
21-Jan-2005 03:02
`Actually, just a minor correction to tekrat at 2d dot com's post:
Change the code....
<?
if(strlen($substring) < 1){
$string = $rep;
}else{
$string = $substring;
}
?>
.... into....
<?
if(strlen($substring) >= 1){
$string = $substring;
}
?>
.... otherwise you'll end up with the elipses (...) for any null strings.`
tekrat at 2d dot com
06-Jan-2005 08:55
`Here's a slightly revised version of the truncation function above.
Theres isn't much of a reason to add in the $rep at the end of the original string is less then the truncation break point.
<?
function truncate($substring, $max = 50, $rep = '...') {
if(strlen($substring) < 1){
$string = $rep;
}else{
$string = $substring;
}
$leave = $max - strlen ($rep);
if(strlen($string) > $max){
return substr_replace($string, $rep, $leave);
}else{
return $string;
}
}
?>`
danieldoorduin at hotmail dot com
10-Dec-2004 02:48
`Using substr_replace() can be avoided by using substr() instead:
<?
$string = substr($string, 0, $position_needle).$replace.substr($string, $position_needle+$length_needle);
?>
This can be useful when you need to replace parts of multibyte strings like strings encoded with utf-8. There isn't a multibute variant for substr_replace(), but for php substr() there is mb_substr(). For more information on multibyte strings see http://nl3.php.net/manual/en/ref.mbstring.php`
titbits at nospam-4logical dot co dot uk
04-Aug-2004 02:28
`A simple but useful 'pluralize' function using substr_replace:
function pluralize($noun) {
if ($noun{strlen($noun) -1} == "y")
$noun = substr_replace($noun, "ies", strlen($noun) -1);
else
$noun .= "s";
return $noun;
}
Handy when displaying dynamic text.`
dmron
17-Jun-2004 04:34
`Regarding "...", even the short functions are too long and complicated, and there's no need to use substr_replace. substr() works better and is way faster prior to 4.3.5 as the below poster stated.
function shorten( $str, $num = 100 ) {
if( strlen( $str ) > $num ) $str = substr( $str, 0, $num ) . "...";
return $str;
}`
philip
13-May-2004 12:55
`The substr_replace() function is extremely slow in PHP versions prior to 4.3.5 and 5.0.0 so consider using an alternative before this time.`
tony at outshine dot com
10-May-2004 02:25
`The comment by geniusdex is a good one. Short, simple functions are the best. But if the string is not longer than the limit set, NOTHING is returned. Here is the function re-done to always return a string:
<?php
function dot($str, $len, $dots = "...") {
if (strlen($str) > $len) {
$dotlen = strlen($dots);
$str = substr_replace($str, $dots, $len - $dotlen);
}
return $str;
}
?>`
geniusdex ( at ) brz ( dot ) nu
23-Feb-2004 07:33
`This is my version of making dotted strings:
<?php
function dot($str, $len, $dots = "...") {
if (strlen($str) > $len) {
$dotlen = strlen($dots);
substr_replace($str, $dots, $len - $dotlen);
}
}
?>`
Thijs Wijnmaalen (thijs[at]nllinux.nl)
20-Jan-2004 11:05
`I wrote a function that you can use for example in combination with a search script to cut off the articles that are too long.
<?php
function substr_index($text, $maxChars = 20, $splitter
= '...') {
$theReturn = $text;
$lastSpace = false;
if (strlen($text) > $maxChars) {
$theReturn = substr($text, 0, $maxChars - 1);
if (in_array(substr($text, $maxChars - 1, 1),
array(' ', '.', '!', '?'))) {
$theReturn .= substr($text, $maxChars, 1);
} else {
$theReturn = substr($theReturn, 0, $maxChars -
strlen($splitter));
$lastSpace = strrpos($theReturn, ' ');
if ($lastSpace !== false) {
$theReturn = substr($theReturn, 0, $lastSpace);
}
if (in_array(substr($theReturn, -1, 1), array(','))) {
$theReturn = substr($theReturn, 0, -1);
}
$theReturn .= $splitter;
}
}
return $theReturn;
}
?>`
neon at lordneon dot com
05-Nov-2003 04:40
`The easiest way (I think) to add trailing dots after a string which in my case are too long is:
<?
function dots($num, $string) {
if (strlen($string) < $num) {
$string = substr_replace($string, '...', '-10', $num);
}
return $string;
}
Then on your page do something like:
<? echo dots("30" $row['title']); ?>
if the string is greater than the specific number it'll replace 3 dots.
I hope this helps =)
?>`
david at ethinkn dot com
05-Jul-2003 05:36
`Here is a simple function to shorten a string and add an ellipsis
<?php
/**
* truncate() Simple function to shorten a string and add an ellipsis
*
* @param string $string Origonal string
* @param integer $max Maximum length
* @param string $rep Replace with... (Default = '' - No elipsis -)
* @return string
* @author David Duong
**/
function truncate ($string, $max = 50, $rep = '') {
$leave = $max - strlen ($rep);
return substr_replace($string, $rep, $leave);
}
echo truncate ('akfhslakdhglksjdgh', 10, '...');
// Returns akfhsla... (10 chrs)
?>`
thomasNOSPAM at sportentranceNOSPAM dot com
08-Oct-2002 03:01
`To abbreviate links into '...' if they outreach a certain amount of space; use the preg_replace function instead.
For instance you grabbed the headlines of a news site for use on your own page and the lines are to long:
asuming the raw material is stored in $unedited;
$edited = preg_replace("/(>)([[:print:]]{52,})(<)/e", "'\\1'.substr_replace('\\2 ', '...', '48').'\\3'", $unedited);
echo $edited;
This will shorten strings longer than 52 characters into 51 characters, with the last being three dots...`
klaas at group94 dot com
13-Feb-2002 10:38
`THE DOT DOT DOT ISSUE
PROBLEM:
You want to abbreviate a string.
E.g. You want "BritneySpears" to show as "BritneySpe...", being only the ten first characters followed by "..."
SOLUTION:
<?
$oRIGINAL = "BritneySpears";
$sHORTER = substr_replace($oRIGINAL, '...', 10);
echo ($sHORTER);
?>
This will result in BritneySpe...`
28-Sep-2001 08:30
`If you would like to remove characters from the start or end of a string, try the substr() function.
For example, to remove the last three characters from a string:
$string = "To be or not to be.";
$string = substr ($string, 0, -3);`
mrbrown8 at juno dot com
16-Apr-2001 12:16
`Just to add to the examples, if replacement is longer than length, only the length number of chars are removed from string and all of replacement is put in its place, and therefor strlen($string) is inreased.
$var = 'ABCDEFGH:/MNRPQR/';
/* Should return ABCDEFGH:/testingRPQR/ */
echo substr_replace ($var, 'testing', 10, 2);`
stefan at maifei dot com
01-Apr-2001 01:33
`If you are trying to use -0, I don't think it works. For example:
substr_replace($file,'',-4,0)
There may be an alternative though...`
jgainey at infoave dot net
13-Mar-2001 06:29
`[Editor's note: for a much simpler solution, use number_format()]
I had a situation in which I needed to add a comma to the third position of a number(the price of something).
<p>
$price = "12000";<br>
$price = substr_replace ($price, ',', -3, 0)";<br>
the result would be 12,000<p>
the -3 counts from right to left. a regular 3 would count from left to right
I hope this helps...`
add a note
substr substr_count

Last updated: Sat, 27 Jan 2007
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