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(PHP 4, PHP 5)
substr_replace — Ersetzt Text innerhalb einer Zeichenkette
substr_replace() ersetzt in einer Kopie von string alle Zeichen, die sich innerhalb der durch die Parameter start und (optional) length festgelegten Grenze befinden, mit der in replacement angegebenen Zeichenkette.
Die Eingabezeichenkette.
Die Ersetzungszeichenkette
Ist start positiv, beginnt die Ersetzung ab der im Offset-Parameter start definierten Stelle innerhalb von string.
Ist start negativ, wird vom Ende der Zeichenkette string bis zum Wert von start rückwärts gezählt und dort mit dem Austausch begonnen.
Ist der Parameter angegeben und positiv, stellt dieser Parameter die Länge des auszuwechselnden Teils von string dar. Ist der Wert negativ, gibt er die Zeichenzahl an, um die ab Ende von string rückwärts gezählt wird. Bis zu dieser Stelle erfolgt dann der Austausch. Ist der Parameter nicht angegeben, wird standardmäßig eine Ersetzung bis zum Ende des Strings (strlen(string )) durchgeführt, das heißt, die Ersetzung endet mit dem Ende von string. Sollte length den Wert null haben, wird die Funktion die Zeichenkette replacement in string an der durch start bezeichneten Stelle einfügen.
Der entstehende String wird zurückgegeben. Ist string ein Array, wird auch ein Array zurückgegeben.
Beispiel #1 substr_replace()-Beispiel
<?php
$var = 'ABCDEFGH:/MNRPQR/';
echo "Original: $var<hr />\n";
/* Die beiden Beispiele ersetzten alle Vorkommen von
$var durch 'bob'. */
echo substr_replace($var, 'bob', 0) . "<br />\n";
echo substr_replace($var, 'bob', 0, strlen($var)) . "<br />\n";
/* Einfügen von 'bob' direkt am Anfang von $var. */
echo substr_replace($var, 'bob', 0, 0) . "<br />\n";
/* Die nächsten beiden Beispiele ersetzen 'MNRPQR' in $var
durch 'bob'. */
echo substr_replace($var, 'bob', 10, -1) . "<br />\n";
echo substr_replace($var, 'bob', -7, -1) . "<br />\n";
/* Entfernen von 'MNRPQR' aus $var. */
echo substr_replace($var, '', 10, -1) . "<br />\n";
?>
Hinweis: Diese Funktion ist binary safe.
It's worth noting that when start and length are both negative -and- the length is less than or equal to start, the length will have the effect of being set as 0.
<?php
substr_replace('eggs','x',-1,-1); //eggxs
substr_replace('eggs','x',-1,-2); //eggxs
substr_replace('eggs','x',-1,-2); //eggxs
?>
Same as:
<?php
substr_replace('eggs','x',-1,0); //eggxs
?>
<?php
substr_replace('huevos','x',-2,-2); //huevxos
substr_replace('huevos','x',-2,-3); //huevxos
substr_replace('huevos','x',-2,-3); //huevxos
?>
Same as:
<?php
substr_replace('huevos','x',-2,0); //huevxos
?>
Another note, if length is negative and start offsets the same position as length, length (yet again) will have the effect as being set as 0. (Of course, as mentioned in the manual, when length is negative it actually represents the position before it)
<?php
substr_replace('abcd', 'x', 0, -4); //xabcd
?>
Same as:
<?php
substr_replace('abcd','x',0,0); //xabcd
?>
<?php
substr_replace('abcd', 'x', 1, -3); //axbcd
?>
Same as:
<?php
substr_replace('abcd', 'x', 1, 0); //axbcd
?>
My problem was that substr_replace() always added $replacement, so i wrote my own function.
This function only adds $replacement, if substr() took action.
The parameter $length is optional - like substr()'s.
Or I was too stupid using $start and $length...
<?php
function substr_replace_provided($string,$replacement,$start,$length=NULL)
{
$tmp=substr($string,$start,$length);
if($string!==$tmp) {
$string = $tmp.$replacement;
}
return $string;
}
?>
This will truncate a longer string to a smaller string of specified length while replacing the middle portion with a separator exactly in the middle.
<?php
$longString = 'abcdefghijklmnopqrstuvwxyz0123456789z.jpg';
$separator = '/.../';
$separatorlength = strlen($separator) ;
$maxlength = 25 - $separatorlength;
$start = $maxlength / 2 ;
$trunc = strlen($longString) - $maxlength;
echo substr_replace($longString, $separator, $start, $trunc);
//prints "abcdefghij/.../56789z.jpg"
?>
Hey everyone, I was noticing that there are a lot of ways below that people are using to write their own string truncation functions, but it kinda seemed like a lot of them went a bit too far out to make any sense to a n00b. Not that I am one anymore, but I though I'd add a note on this topic myself, in hopes that it might help others understand things a little better.
Here's a concept that some people don't know about, or remember to use often enough; You can actually pull individual characters out of a string by referencing that string as though it were an array. Example: If I have the string $s = 'cat', I can use $s[0] to actually get out only the first character of that string, 'c'. I use that same principle below, but I just use a loop to iterate through a string and add the characters to the output variable one by one until the $lenth param has been reached, or until the end of the string.
I hope this can help someone out!
-Admiral Potato
<?php
function admiralsTruncate($string, $length){
settype($string, 'string');
settype($length, 'integer');
for($a = 0; $a < $length AND $a < strlen($string); $a++){
$output .= $string[$a];
}
return($output);
}
$my_string = 'cfcd208495d565ef66e7dff9f98764da';
echo admiralsTruncate($my_string, 6); // outputs: cfcd20
echo '<br>';
echo admiralsTruncate($my_string, 9); // outputs: cfcd20849
?>
This is a good method to check file chmod value:
<?php
$file = "../files/sample.txt";
$rights = decoct(fileperms($file));
echo "File rights: ".substr_replace($rights, "", 0, 3);
?>
Forget all of the mb_substr_replace() implementations mentioned in this page, they're all buggy.
Here is a version that mimics the behavior of substr_replace() exactly:
<?php
if (function_exists('mb_substr_replace') === false)
{
function mb_substr_replace($string, $replacement, $start, $length = null, $encoding = null)
{
if (extension_loaded('mbstring') === true)
{
$string_length = (is_null($encoding) === true) ? mb_strlen($string) : mb_strlen($string, $encoding);
if ($start < 0)
{
$start = max(0, $string_length + $start);
}
else if ($start > $string_length)
{
$start = $string_length;
}
if ($length < 0)
{
$length = max(0, $string_length - $start + $length);
}
else if ((is_null($length) === true) || ($length > $string_length))
{
$length = $string_length;
}
if (($start + $length) > $string_length)
{
$length = $string_length - $start;
}
if (is_null($encoding) === true)
{
return mb_substr($string, 0, $start) . $replacement . mb_substr($string, $start + $length, $string_length - $start - $length);
}
return mb_substr($string, 0, $start, $encoding) . $replacement . mb_substr($string, $start + $length, $string_length - $start - $length, $encoding);
}
return (is_null($length) === true) ? substr_replace($string, $replacement, $start) : substr_replace($string, $replacement, $start, $length);
}
}
?>
I've just taken a look at the post by ntoniazzi and I have a very small correction to make.
In the second if statement, it should be a triple equals, so:
<?php if ($length === null) ?>
It requires the triple equals, for the case of pure insertion, where $length = 0, the double equals, will catch this, causing the string to be cut short. I hope this helps someone.
The preemptive test to see if $string is "too long" shouldn't add strlen($replacement) to $max. $max should represent the absolute maximum length of string returned. The size of the $replacement is irrelevant in that determination.
The rest of the function (unchanged below) operates as defined above. Meaning, the size of the $replacement is subtracted from the $max, so that the returned string is exactly the length of $max.
<?php
function truncate($string, $max = 20, $replacement = '')
{
if (strlen($string) <= $max)
{
return $string;
}
$leave = $max - strlen ($replacement);
return substr_replace($string, $replacement, $leave);
}
?>
the version of my predecessor will add $rep even if the string is shorter than max. fixed version:
<?php
function truncate($string, $max = 20, $rep = '')
{
if (strlen($string) <= ($max + strlen($rep)))
{
return $string;
}
$leave = $max - strlen ($rep);
return substr_replace($string, $rep, $leave);
}
?>
To preserve the filename extension you can call it like this:
truncate([filename], 30, '...' . end(explode('.', [filename])))
PHP version of Java's removeCharAt() function:
<?php
function removeCharAt($str, $int){
return substr_replace($str,"",$int,1);
}
?>
I recently ran across a situation where I need to strip a heavily nested html list such that only the top level was preserved. I started with a regular expression solution, but found that I kept matching the wrong closing ul with an outer opening ul.
This was my alternative solution, and it seems to work well:
<?php
function stripNestedLists($str)
{
$str2 = $str;
$lastStr = $str2;
do
{
// Find the first closing ul
$cul = strpos($str2, '</ul>');
$ul = 0;
$lastUL = 0;
do
{
// Find the next opening ul
$lastUL = $ul;
$ul = strpos($str2, '<ul', $ul+1);
}
while ($ul !== false && $ul < $cul);
$lastStr = $str2;
$str2 = substr_replace($str2, '', $lastUL, $cul-$lastUL+5);
$str2 = trim($str2);
}
while (strlen($str2) > 0);
return $lastStr;
}
?>
Hope this helps someone.
I recently needed a routine that would remove the characters in one string from another, like the regex
<?php
$result = preg_replace("/[$chars]/", "", $string);
?>
and I needed it to be fast, and accept pretty much all input. The regex above won't work when strlen($chars) == 0. I came up with this, admittedly pretty horrible-looking code, that is quite fast:
<?php
function RemoveChars($string, $chars)
{
return isset($chars{0}) ? str_replace($chars{0}, "", strtr($string, $chars, str_pad($chars{0}, strlen($chars), $chars{0}))) : $string;
}
?>
According to my own measurements, the regex in ONLY faster for when strlen($chars) == 1; for longer strings, my routine is faster. What does it do? Let's say you want to remove the period, the comma and the exclamation mark from a string, like so:
$result = RemoveChars("Isn't this, like, totally neat..!?", ".?!");
The str_pad function creates a string equal in length to the string that contains the character to be removed, but consisting only of the first character of that string:
The input is ".,!"
The output is "..."
The strtr function translates all characters in the string-to-be-processed ("Isn't this...") that also occur in the input (".,!") to the characters in the same position in the output ("..."). In other words:
Isn't this, like, totally neat..!?
becomes
Isn't this. like. totally neat....
Finally, the first character from the input (".,!") which happens to be, again, the period, is removed from that string by the str_replace call:
Isn't this like totally neat?
The function needs to check is $chars has at least one character, or else the str_pad function will fail. If it's empty, then the unprocessed string is returned.
Almost... In the previous note, change this :
<?php
function mb_substr_replace($string, $replacement, $start, $length=null, $encoding=null) {
if ($encoding == null) $encoding = mb_internal_encoding();
if($start < 0) $start = mb_strlen($string) + $start;
[...]
?>
There is a mistake in the mb_substr_replace function below, when the $length parameter is given negative. Here is a working version.
<?php
//Check to see if it exists in case PHP has this function later
if (!function_exists("mb_substr_replace")){
//Same parameters as substr_replace with the extra encoding parameter.
function mb_substr_replace($string, $replacement, $start, $length=null, $encoding=null) {
if ($encoding == null) $encoding = mb_internal_encoding();
if ($length == null) {
return mb_substr($string, 0, $start, $encoding) . $replacement;
}
else {
if($length < 0) $length = mb_strlen($string, $encoding) - $start + $length;
return
mb_substr($string, 0, $start, $encoding) .
$replacement .
mb_substr($string, $start + $length, mb_strlen($string, $encoding), $encoding);
}
}
}
?>
I like the truncate function below...however, I found a few issues. Particularly if you have content that may have any kind of punctuation in it (?, !, ?!?, --, ..., .., ;, etc.)
The older function would end up looking like "blah blah?..." or "blah blah,..." which doesn't look so nice to me...
Here's my fix. It removes all trailing punctuation (that you include in the $punctuation string below) and then adds an ellipse. So even if it has an ellipse with 3 dots, 2 dots, 4 dots, it'll be removed, then re-added.
<?php
function truncate($text,$numb,$etc = "...") {
$text = html_entity_decode($text, ENT_QUOTES);
if (strlen($text) > $numb) {
$text = substr($text, 0, $numb);
$text = substr($text,0,strrpos($text," "));
$punctuation = ".!?:;,-"; //punctuation you want removed
$text = (strspn(strrev($text), $punctuation)!=0)
?
substr($text, 0, -strspn(strrev($text), $punctuation))
:
$text;
$text = $text.$etc;
}
$text = htmlentities($text, ENT_QUOTES);
return $text;
}
?>
I also needed a sort of "middle" truncate. The above function truncates around the end, but if you want to truncate around the middle (ie "Hello this is a long string." --> "Hello this ... long string.") you can use this (requires the truncate function):
<?php
function mtruncate($text, $numb, $etc = " ... ") {
$first_part = truncate(truncate($text, strlen($text)/2, ""), $numb/2, "");
$second_part = truncate(strrev(truncate(strrev($text), strlen($text)/2, "")), $numb/2, "");
return $first_part.$etc.$second_part;
}
?>
I've made a minor amendment to the function in the post below, to strip away the full stop (period) if the truncation occurs at the exact end of a sentence (the full stop spoils the ellipsis):
<?php
function truncate($text,$numb) {
$text = html_entity_decode($text, ENT_QUOTES);
if (strlen($text) > $numb) {
$text = substr($text, 0, $numb);
$text = substr($text,0,strrpos($text," "));
//This strips the full stop:
if ((substr($text, -1)) == ".") {
$text = substr($text,0,(strrpos($text,".")));
}
$etc = "...";
$text = $text.$etc;
}
$text = htmlentities($text, ENT_QUOTES);
return $text;
}
//Call function
truncate($text, 75);
The two truncate functions provided below, have some major short comings.
1. They may cut a word in half
2. In case you are using htmlentities to get user input or are using wysiwyg editors to get user input, you can get truncated text like "he told C&eac..." instead of "he told Cécile" or "he told".
Here is what I use -
<?php
function truncate($text,$numb) {
// source: www.kigoobe.com, please keep this if you are using the function
$text = html_entity_decode($text, ENT_QUOTES);
if (strlen($text) > $numb) {
$text = substr($text, 0, $numb);
$text = substr($text,0,strrpos($text," "));
$etc = " ...";
$text = $text.$etc;
}
$text = htmlentities($text, ENT_QUOTES);
return $text;
}
// Now, to use this function, you can call that as -
truncate($text, 75);
?>
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);
}
}
}
}
?>
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 $str;
}
?>
I suggest changing the function suggested by Guru Evi slightly. I found that it doesn't work as written here.
Original:
function add_3dots($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,"...",$max_length);
If your string is not long enough to meet what you specify in start and length then the replacement string is added towards the end of the string.
I wanted to replace the end of the string with ... if the string was too long to display (for instance article preview on a website). The problem was that my string was sometimes not that long and it still added the replacement string. So I wrote a function to replace substr_replace in my website:
function add_3dots($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)
Here's a slightly revised version of the truncation function above.
Theres isn't much of a reason to add in the $rep at the end of the original string is less then the truncation break point.
<?php
function truncate($substring, $max = 50, $rep = '...') {
if(strlen($substring) >= 1){
$string = $substring;
}
$leave = $max - strlen ($rep);
if(strlen($string) > $max){
return substr_replace($string, $rep, $leave);
}else{
return $string;
}
}
?>
[EDIT BY danbrown AT php DOT net: Contains a bugfix by (ogt AT parasane DOT com) (which was me ;-P) from 21-JAN-05 at 11:02 EST.]
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
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.
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 $str;
}
The substr_replace() function is extremely slow in PHP versions prior to 4.3.5 and 5.0.0 so consider using an alternative before this time.
The comment by geniusdex is a good one. Short, simple functions are the best. But if the string is not longer than the limit set, NOTHING is returned. Here is the function re-done to always return a string:
<?php
function dot($str, $len, $dots = "...") {
if (strlen($str) > $len) {
$dotlen = strlen($dots);
$str = substr_replace($str, $dots, $len - $dotlen);
}
return $str;
}
?>
This is my version of making dotted strings:
<?php
function dot($str, $len, $dots = "...") {
if (strlen($str) > $len) {
$dotlen = strlen($dots);
substr_replace($str, $dots, $len - $dotlen);
}
}
?>
I wrote a function that you can use for example in combination with a search script to cut off the articles that are too long.
<?php
function substr_index($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 $theReturn;
}
?>
The easiest way (I think) to add trailing dots after a string which in my case are too long is:
<?
function dots($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 =)
?>
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)
?>
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...
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...
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);
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);
[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).
<?php
$price = "12000";
$price = substr_replace ($price, ',', -3, 0)";
?>
the result would be 12,000
the -3 counts from right to left. a regular 3 would count from left to right
I hope this helps...
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