str_repeat
I'm sorry. I can't believe it: I messed up again. Something that I forgot is that the php empty() function considers the number zero (0) as an empty value. Therefore, we need to change our if statement to the following:
<?php
if ($i[0] !== null) $subject .= $replace[$i[0]];
?>
If we left it how it was, the replace ignores the first element of the arrays. ($array[0])
The reason that I used !empty() before, is that I wasn't sure what array_keys() returns if the element is not found (null? and empty string?), since both null and the empty string print out the same and I couldn't find what it returned in this case, in the manual.
The final, working function would look like:
<?php
function str_replace_once($search, $replace, $subject) {
$newArr = str_split($subject);
$subject = '';
foreach ($newArr as $nchar)
{
$i = array_keys($search, $nchar);
if ($i[0] !== null) $subject .= $replace[$i[0]];
else $subject .= $nchar;
}
return $subject;
}
?>
str_replace
(PHP 4, PHP 5)
str_replace — Replace all occurrences of the search string with the replacement string
Description
This function returns a string or an array with all occurrences of search in subject replaced with the given replace value.
If you don't need fancy replacing rules (like regular expressions), you should always use this function instead of ereg_replace() or preg_replace().
Parameters
If search and replace are arrays, then str_replace() takes a value from each array and uses them to do search and replace on subject . If replace has fewer values than search , then an empty string is used for the rest of replacement values. If search is an array and replace is a string, then this replacement string is used for every value of search . The converse would not make sense, though.
If search or replace are arrays, their elements are processed first to last.
- search
-
- replace
-
- subject
-
If subject is an array, then the search and replace is performed with every entry of subject , and the return value is an array as well.
- count
-
Note: If passed, this will hold the number of matched and replaced needles.
Return Values
This function returns a string or an array with the replaced values.
ChangeLog
| Version | Description |
|---|---|
| 5.0.0 | The count parameter was added. |
| 4.3.3 | The behaviour of this function changed. In older versions a bug existed when using arrays as both search and replace parameters which caused empty search indexes to be skipped without advancing the internal pointer on the replace array. This has been corrected in PHP 4.3.3, any scripts which relied on this bug should remove empty search values prior to calling this function in order to mimic the original behavior. |
| 4.0.5 | Most parameters can now be an array. |
Examples
Example #1 str_replace() examples
<?php
// Provides: <body text='black'>
$bodytag = str_replace("%body%", "black", "<body text='%body%'>");
// Provides: Hll Wrld f PHP
$vowels = array("a", "e", "i", "o", "u", "A", "E", "I", "O", "U");
$onlyconsonants = str_replace($vowels, "", "Hello World of PHP");
// Provides: You should eat pizza, beer, and ice cream every day
$phrase = "You should eat fruits, vegetables, and fiber every day.";
$healthy = array("fruits", "vegetables", "fiber");
$yummy = array("pizza", "beer", "ice cream");
$newphrase = str_replace($healthy, $yummy, $phrase);
// Use of the count parameter is available as of PHP 5.0.0
$str = str_replace("ll", "", "good golly miss molly!", $count);
echo $count; // 2
// Order of replacement
$str = "Line 1\nLine 2\rLine 3\r\nLine 4\n";
$order = array("\r\n", "\n", "\r");
$replace = '<br />';
// Processes \r\n's first so they aren't converted twice.
$newstr = str_replace($order, $replace, $str);
// Outputs: apearpearle pear
$letters = array('a', 'p');
$fruit = array('apple', 'pear');
$text = 'a p';
$output = str_replace($letters, $fruit, $text);
echo $output;
?>
Notes
Note: This function is binary-safe.
Note: This function is case-sensitive. Use str_ireplace() for case-insensitive replace.
add a note
User Contributed Notesstr_replace
max at efoxdesigns dot com
06-Aug-2008 10:13
06-Aug-2008 10:13
max at efoxdesigns dot com
06-Aug-2008 09:28
06-Aug-2008 09:28
Sorry, folks. That last note I put up won't work quite correctly. Unlike str_replace(), that snippet I showed you will replace any characters that aren't in your $search array with an empty string.
To correct this behavior, add this check to the foreach loop:
<?php
//...
if (!empty($i[0])) $subject .= $replace[$i[0]];
else $subject .= $nchar; //now, if the search character isn't found (ie, we don't care about it), it will stay the same, instead of getting replaced by an empty string.
?>
The whole thing would look like the following, if you were to put it into a function:
<?php
function char_replace_once($search, $replace, $subject) {
$newArr = str_split($subject);
$subject = '';
foreach ($newArr as $nchar)
{
$i = array_keys($search, $nchar);
if (!empty($i[0])) $subject .= $replace[$i[0]];
else $subject .= $nchar;
}
return $subject;
}
?>
I'm sure it may not be as efficient as str_replace(), but it successfully replaces characters, correctly.
ONE OTHER IMPORTANT THING TO NOTE: Unlike I said before, this will only work for character replacement - not string replacement. The reason, of course, is that the original string gets split into an array, who's members are only one character. Sorry about that.
That drawback aside, though, this is still a useful function for doing complete, accurate character replacement.
max at efoxdesigns dot com
06-Aug-2008 08:29
06-Aug-2008 08:29
Note that the str_replace() function is recursive. This is not usually a problem, unless you are trying to do a replace in which a character or string occurs in the $search array, after the same character or string occurs in the $replace array. (For instance, imagine doing a global character replace.)
To demonstrate, take a look at the folowing:
<?php
$search = array('q','w','e','r','t','y','u');
$replace = array('z','s','d','e','y','f','g');
$mystring = 'qwertyu';
//Outputs: zsdeffg
echo str_replace($search, $replace, $mystring);
?>
As you would expect, the q gets replaced by a z, the w by an s, and so on. Everything is correct, except that the t doesn't seem to have been replaced by a y. This is not entirely true, however. What happened is that it did, indeed get replaced by a y, but then on the next pass of the str_replace() function, str_replace() found a y and replaced it with an f.
To get this to work as we'd like (every letter in the $search array replaced by the cooresponding spot in the $replace array), we can do something like the following:
<?php
$search = array('q','w','e','r','t','y','u');
$replace = array('z','s','d','e','y','f','g');
$mystring = 'qwertyu';
//Outputs: zsdeffg (Not what we wanted.)
echo str_replace($search, $replace, $mystring);
$newArr = str_split($mystring); //split $mystring into an array of characters. For php4, you'll have to create the str_split() function.
$newstring = '';
foreach ($newArr as $nchar)
{
$i = array_keys($replace, $nchar); //get the key(s) in the $search array for the character we're replacing. (we assume it occurs only once.) Returns an array of length, 1.
$newstring .= $replace[$i[0]]; //find the character in the $replace array that matches the position of the one we're replacing, and add it to $newstring.
}
//Outputs: zsdeyfg
echo $newstring;
?>
This time, as you can see, there is a y in place of the t, which was what we wanted. :)
Hope that clears up any confusion for anyone wondering why their strings aren't getting replaced as they'd expect.
troy at troyonline dot com
23-Jun-2008 07:18
23-Jun-2008 07:18
Yet another deep replace function:
<?php
function str_replace_deep( $search, $replace, $subject)
{
$subject = str_replace( $search, $replace, $subject);
foreach ($subject as &$value)
is_array( $value) and $value =str_replace_deep( $search, $replace, $value);
return $subject;
}
?>
jaimthorn at yahoo dot com
20-Jun-2008 01:52
20-Jun-2008 01:52
On the 19th of June, 2008, max at bitsonnet dot com posted a function interpolate that used create_function. I'd never seen create_function before and I thought it was very educational. Thanks, Maxim!
However, the interpolate function can be improved, speed-wise:
<?php
function interpolate2($template, $hash, $prefix = '#{', $postfix = '}')
{
$tmp = array();
foreach($hash as $k => $v)
{
$tmp[$prefix . $k . $postfix] = $v;
}
return str_replace(array_keys($tmp), array_values($tmp), $template);
}
echo interpolate2('Hello, #{username}. Welcome to #{site}.', array('username' => 'World', 'site' => 'php.net'));
?>
According to my own tests, this version is somewhere between 4 and 5 times faster.
Note, btw, that I used a very similar function on the sprintf page.
max at bitsonnet dot com
19-Jun-2008 11:00
19-Jun-2008 11:00
I always miss interpolate functionality in PHP, so I wrote this little helper method. It allows you to specify your own markup using $prefix and $postfix.
<?php
# Interpolate a string using hash.
# by Maxim Chernyak ( http://mediumexposure.com )
function interpolate($template, $hash, $prefix = '#{', $postfix = '}' ) {
$tokenize = create_function('$token', 'return "'. $prefix .'".$token."'.$postfix.'";');
$keys = array_keys($hash);
$values = array_values($hash);
$keys = array_map($tokenize, $keys);
return str_replace($keys, $values, $template);
}
?>
For example:
<?php
$result = interpolate('Hello, #{username}. Welcome to #{site}.', array('username' => 'Hakunin', 'site' => 'php.net'));
?>
cclarkson at htcomp dot net
28-Apr-2008 12:32
28-Apr-2008 12:32
The example presented by bladescope at googlemail dot com has a couple of syntax errors. This works:
<?php
$template = "The {color} {object} is in {location}";
$array = array(
'{object}' => 'Ball',
'{color}' => 'Red',
'{location}' => 'The Playground',
);
foreach ($array as $search => $replace) {
$template = str_replace($search, $replace, $template);
}
print $template;
?>
I did not check it for speed or thoroughly test it, but this function seems to do the same thing more succinctly.
<?php
function template($array, $template) {
return str_replace(
array_keys($array),
array_values($array),
$template
);
}
echo template(
array(
'{color}' => 'red',
'{object}' => 'ball',
'{location}' => 'the playground',
),
'The {color} {object} is in {location}.'
);
?>
David Gimeno i Ayuso (info at sima dot cat)
09-Aug-2007 09:50
09-Aug-2007 09:50
This is the functions I wrote for the problem reported above, str_replace in multi-dimensional arrays. It can work with preg_replace as well.
<?php
function array_replace($SEARCH,$REPLACE,$INPUT) {
if (is_array($INPUT) and count($INPUT)<>count($INPUT,1)):
foreach($INPUT as $FAN):
$OUTPUT[]=array_replace($SEARCH,$REPLACE,$FAN);
endforeach;
else:
$OUTPUT=str_replace($SEARCH,$REPLACE,$INPUT);
endif;
return $OUTPUT;
}
?>
David Gimeno i Ayuso (info at sima dot cat)
09-Aug-2007 09:22
09-Aug-2007 09:22
With PHP 4.3.1, at least, str_replace works fine when working with single arrays but mess it all with two or more dimension arrays.
<?php
$subject = array("You should eat this","this","and this every day.");
$search = "this";
$replace = "that";
$new = str_replace($search, $replace, $subject);
print_r($new); // Array ( [0] => You should eat that [1] => that [2] => and that every day. )
echo "<hr />";
$subject = array(array("first", "You should eat this")
,array("second","this")
,array("third", "and this every day."));
$search = "this";
$replace = "that";
$new = str_replace($search, $replace, $subject);
print_r($new); // Array ( [0] => Array [1] => Array [2] => Array )
?>
mjaque at ilkebenson dot com
22-Jul-2007 10:28
22-Jul-2007 10:28
In order to replace carriage return characters from form inputs, if everything else fails, you can try:
<?php
$new_text = str_replace(chr(13).chr(10), '_', $original_text);
?>
And in order to show the line feeds in a javascript alert, you can do:
<?php
$new_text = str_replace(chr(13).chr(10), '\n', $original_text);
?>
cm at k-a-p dot com
13-Jun-2007 03:47
13-Jun-2007 03:47
Here is a version that allows for empty multidimensional arrays:
<?php
function str_replace_array ($search, $replace, $subject) {
if (is_array($subject)) {
foreach ($subject as $id=>$inner_subject) {
$subject[$id]=str_replace_array($search, $replace, $inner_subject);
}
} else {
$subject=str_replace($search, $replace, $subject);
}
return $subject;
}
?>
tim at hysniu dot com
05-Jun-2007 08:27
05-Jun-2007 08:27
I found that having UTF-8 strings in as argument didnt
work for me using heavyraptors function.
Adding UTF-8 as argument on htmlentities
fixed the problem.
cheers, tim at hysniu.com
<?php
function replace_accents($str) {
$str = htmlentities($str, ENT_COMPAT, "UTF-8");
$str = preg_replace(
'/&([a-zA-Z])(uml|acute|grave|circ|tilde);/',
'$1',$str);
return html_entity_decode($str);
}
?>
kole
26-Feb-2007 02:48
26-Feb-2007 02:48
My input is MS Excel file but I want to save ‘,’,“,” as ',',",".
$badchr = array(
"\xc2", // prefix 1
"\x80", // prefix 2
"\x98", // single quote opening
"\x99", // single quote closing
"\x8c", // double quote opening
"\x9d" // double quote closing
);
$goodchr = array('', '', '\'', '\'', '"', '"');
str_replace($badchr, $goodchr, $strFromExcelFile);
Works for me.
rlee0001 at sbcglobal dot net
16-Feb-2007 09:30
16-Feb-2007 09:30
This is a more rigid alternative to spectrereturns at creaturestoke dot com's replace_different function:
<?php
function str_replace_many ($search, $replacements, $subject) {
$index = strlen($subject);
$replacements = array_reverse($replacements);
if (count($replacements) != substr_count($subject, $search)) {
return FALSE;
}
foreach ($replacements as $replacement) {
$index = strrpos(substr($subject, 0, $index), $search);
$prefix = substr($subject, 0, $index);
$suffix = substr($subject, $index + 1);
$subject = $prefix . $replacement . $suffix;
}
return $subject;
}
?>
This will return false if there are a different number of $replacements versus number of occurrences of $search in $subject. Additionally, $search much be exactly one character (if a string is provided, only the first character in the string will be used). Examples:
<?php
echo str_replace_many('?',array('Jane','banana'),'? is eating a ?.');
?>
prints: "Jane is eating a banana."
15-Jan-2007 10:42
Before spending hours searching your application why it makes UTF-8 encoding into some malformed something with str_replace, make sure you save your PHP file in UTF-8 (NO BOM).
This was at least one of my problems.
Boris DOT Christ AT laposte DOT net
27-Nov-2006 10:32
27-Nov-2006 10:32
I create a little function to transform (to example) "User@example.net" in "user AT example DOT net" and conversely.
<?php
function code_mail($email) {
if(preg_match('`^.+@.+\..{1,5}$`', $email)) { //email format
$email = str_replace('.', ' DOT ', $email); //replace . by dot
$email = str_replace('@', ' AT ', $email); //replace @ by at
return $email;
}
else { //not email format
return false;
}
}
function decode_mail($email) { //on décode...
$email = str_replace(' DOT ', '.', $email); //replace dot by .
$email = str_replace(' AT ', '@', $email); //replace at by @
return $email;
}
?>
Ota L.
11-Nov-2006 12:14
11-Nov-2006 12:14
This simple function may be usefull to convert czech text from cp-1250 encoding to iso-8859-2 (convert S, T and Z with caron).
I use it because mbstring does not support windows-1250 (i.e. mb_convert_encoding(win2iso($text), "utf-8", "iso-8859-2");).
<?php
function win2iso($text)
{
$win = array ("\x9A", "\x9D", "\x9E", "\x8A", "\x8D", "\x8E");
$iso = array ("\xB9", "\xBB", "\xBE", "\xA9", "\xAB", "\xAE");
return str_replace($win, $iso, $text);
}
?>
webmaster at unitedscripters dot com
30-Jul-2006 03:50
30-Jul-2006 03:50
You may have decided to save in a non ANSI format a file so that a few fancy chars that you plan to replace can be viewed by your human eyes too (aren't all those empty rectangles a curse?).
Fine. All works just fine in the file, and all the replacements occur as intended.
You make a class out of those codes.
Then you put this non ANSI encoded file in your includes folder. Isn't it a nice class?
Well, don't call in such class as an include into another file, if the latter is ANSI : the char look up tables will NOT match, and the latter file (say the caller) will (I guess) feed ANSI codes to the included file (say the called) and you will spend a day wondering why the class methods work 100% well when you perform replacements directly from within the called, and yet the very same methods, even with the very same copied-and-pasted examples, fail miserably when performed from within the caller.
A very "stimulating" debugging!
I just came out from a night spent on this. I just forgot the included class file wasn't saved as an ANSI.
<?php
class regexp{
//blah blah...
var $toascii=array( 'Ã' => 'A');
//blah blah
function toascii_replace($input, $addSlashes=0){
return (!$addSlashes)? strtr($input, $this->toascii): addslashes( strtr($input, $this->toascii) );
}
}
$r=new regexp();
$input='Ã';
print $r->toascii_replace($input);//prints A
?>
Now save that class (remove the print statement too) in a format that isn't ANSI, say UTF-8.
Then do:
<?php
include_once('regexp.php');
$r=new regexp();
$input='Ã';
print $r->toascii_replace($input);//prints... Ã
?>
IDENTICAL codes, different results.
note: the class uses strtr but would happen with all replacing oriented functions, and I can pester all the documentations. Maybe I worked out the wrong reason, but the behaviour occurs.
matt wheaton
30-Mar-2006 05:40
30-Mar-2006 05:40
As an effort to remove those Word copy and paste smart quotes, I've found that this works with UTF8 encoded strings (where $text in the following example is UTF8). Also the elipsis and em and en dashes are replaced.
There is an "invisible" character after the †for the right side double smart quote that doesn't seem to display here. It is chr(157).
<?php
$find[] = '“'; // left side double smart quote
$find[] = 'â€'; // right side double smart quote
$find[] = '‘'; // left side single smart quote
$find[] = '’'; // right side single smart quote
$find[] = '…'; // elipsis
$find[] = '—'; // em dash
$find[] = '–'; // en dash
$replace[] = '"';
$replace[] = '"';
$replace[] = "'";
$replace[] = "'";
$replace[] = "...";
$replace[] = "-";
$replace[] = "-";
$text = str_replace($find, $replace, $text);
?>
hermes at andycostell dot com
11-Dec-2004 08:57
11-Dec-2004 08:57
A simple function to take out the double line breaks "%0D%0A" from a string made from text being wrapped in a textarea and turn them into single line breaks.
<?php
function remove_extra_linebreaks($string) {
$new_string=urlencode ($string);
$new_string=ereg_replace("%0D", " ", $new_string);
$new_string=urldecode ($new_string);
return $new_string;
}
?>
I use it when taking text from a textarea with wrap="hard" that I'm emailing out on the next page, for instance. Otherwise there's an extra empty line between each line in the emailed text, which looks nasty!
David Gimeno i Ayuso (info at sima-pc dot com)
25-Aug-2003 03:12
25-Aug-2003 03:12
Take care with order when using arrays in replacement.
<?php
$match=array("ONE","TWO","THREE");
$replace=array("TWO WORDS","MANY LETTERS","OTHER IDEAS");
$sample="ONE SAMPLE";
echo str_replace($match,$replace,$sample);
?>
It will show: "MANY LETTERS WORDS SAMPLE"
That is, after replacing "ONE" with "TWO WORDS", process follows with next array item and it changes "TWO" with "MANY LETTERS".
imho at auspantheon dot com
27-Jun-2003 01:08
27-Jun-2003 01:08
An excellent way of making sure your pages don't contain "invalid entities", IE. Valid HTML is using the following function.
Most forum packages / extensions provide output containing the symbol &, we don't want this!
<?php
function include_safe ($file)
{
$array = file($file);
foreach ($array as $line) {
print str_replace('&', '&', $line);
}
}
?>
The same technique could also be used in conjuntion with htmlmspecialchars or htmlentities.
13-Jun-2003 12:59
Having a string for $search and an array for $replace won't work. This is mentioned on the preg_replace() page where it's described as not making sense, but not here.
But one could interpret such a situation and hence implement str_replace so that a signature of (string, array, string) or even (string, array, array) would "work". The result of
<?php
$search = '*';
$replace = range(1,20);
$subject = '{*}';
$result = str_replace($search, $replace, $subject);
?>
could be an array of elements "{1}", "{2}", "{3}" .... In other words it would have the same effect as
<?php
$search = '*';
$replace = range(1,20);
$subject = '{*}';
$result = array();
foreach($replace as $r) {
$result[] = str_replace($search, $r, $subject);
}
?>
I leave more elaborate applications to your imagination :)
The result of a str_replace(string,array,array) would therefore presumably be an array of arrays, with its dimensions indexed by the two arrays passed in. But then there's the question of which is the first dimension and which is the second.
rit at NOSPAMchatol dot com
07-Jan-2003 01:32
07-Jan-2003 01:32
I was trying to remove newlines from a textarea input (result of failed submission of parent form - JS verification not possible in this situation) to send back to the textarea via javascript (due to the fact that setting the value in the textarea tag does not work) and had a hard time figuring it out.
If anyone cares, try replacing: "%0D%0A" which is how I found it(changed my POST method to GET) and tracked it down in the address bar of my browser. Hope this helps, I sure wish someone else had posted it earlier!
art at zollerwagner dot com
10-Oct-2002 12:26
10-Oct-2002 12:26
To use one or two arrays in str_replace,
this appears to be the correct format:
<?php
str_replace(array('1st_current_needle_element', '2nd', '3rd'), array('1st_new_needle_element', '2nd', '3rd'), $haystack)
?>
Example of a single array, which simply removes the characters in the first array:
<?php
$text=str_replace(array('<', '>', '\\', '/', '='), "", $text);
?>
This will delete the chars: < > \ / =
It could also be done by first defining the array(s), like this:
<?php
$targetChars=array('<', '>', '\\', '/', '=');
$text=str_replace($targetChars, "", $text);
?>