strrchr
manfred at werkzeugH dot at, your version works, but do you think it has an advantage over mine? Just wondering if I should update my scripts.
carmel.alex at gmail.com, your version fails with utf8_strrev($string, true). It's something about spaces.
For example, you turn
This software was protected by 2000 patents since 2001
into
2001 ecnis stnetap2000 yb detcetorp saw erawtfos sihT
(note the "stnetap2000").
strrev
(PHP 4, PHP 5)
strrev — Reverse a string
Description
string strrev
( string $string
)
Returns string , reversed.
Parameters
- string
-
The string to be reversed.
Return Values
Returns the reversed string.
Examples
Example #1 Reversing a string with strrev()
<?php
echo strrev("Hello world!"); // outputs "!dlrow olleH"
?>
add a note
User Contributed Notesstrrev
lwc at trashymail dot com
19-Jun-2008 02:00
19-Jun-2008 02:00
manfred at werkzeugH dot at
27-May-2008 01:35
27-May-2008 01:35
here is my version for strings with utf8-characters represented as numerical entities (e.g. Ӓ)
function utf8_entities_strrev($str, $preserve_numbers = true)
{
//split string into string-portions (1 byte characters, numerical entitiesor numbers)
$parts=Array();
while ($str)
{
if ($preserve_numbers && preg_match('/^([0-9]+)(.*)$/',$str,$m))
{
// number-flow
$parts[]=$m[1];
$str=$m[2];
}
elseif (preg_match('/^(\&#[0-9]+;)(.*)$/',$str,$m))
{
// numerical entity
$parts[]=$m[1];
$str=$m[2];
}
else
{
$parts[]=substr($str,0,1);
$str=substr($str,1);
}
}
$str=implode(array_reverse($parts),"");
return $str;
}
Anonymous
18-Dec-2007 11:30
18-Dec-2007 11:30
MOD10, Modulus10 or also called LUHN10 will generate a valid check digit.
<?php
$inv = "34586";
echo $inv . checkdigit($inv);
// Outputs 345868
function checkdigit($num) {
$sum = 0;
$pos = 0;
$rev = strrev($num);
$len = strlen($num);
if ($len % 2 == 0) $len += 1;
while ($pos < $len) {
$odd = $rev[$pos] * 2;
if ($odd > 9) {
$odd -= 9;
}
$sum += $odd;
if ($pos != ($len - 2)) {
$sum += $rev[$pos +1];
}
$pos += 2;
}
return ((floor($sum/10) + 1) * 10 - $sum) % 10;
}
?>
carmel.alex at gmail.com
21-Dec-2006 07:38
21-Dec-2006 07:38
to lwc at mytrashmail dot com, take it easy.
function utf8_strrev($str, $reverse_numbers = true){
$pattern = $reverse_numbers ? '/./us' : '/(\d+)?./us';
preg_match_all($pattern, $str, $ar);
return join('',array_reverse($ar[0]));
}
lwc at mytrashmail dot com
14-Oct-2006 01:01
14-Oct-2006 01:01
just as well for UTF-8 usages = I meant also for NONE UTF-8 usages (to keep the numbers unchanged)
lwc at mytrashmail dot com
13-Oct-2006 10:35
13-Oct-2006 10:35
/*
Here's a function that adds to carmel.alex's utf-8 encoding support the ability NOT to reverse numbers (for example when you output a phrase as a parameter for a SWF file that can't handle RTL languages itself, but obviously any numbers should remain the same as in the original phrase).
Note that it can be used just as well for UTF-8 usages if you want the numbers to remain intact:
*/
function utf8_strrev($str, $reverse_numbers) {
preg_match_all('/./us', $str, $ar);
if ($reverse_numbers)
return join('',array_reverse($ar[0]));
else {
$temp = array();
foreach ($ar[0] as $value) {
if (is_numeric($value) && !empty($temp[0]) && is_numeric($temp[0])) {
foreach ($temp as $key => $value2) {
if (is_numeric($value2))
$pos = ($key + 1);
else
break;
}
$temp2 = array_splice($temp, $pos);
$temp = array_merge($temp, array($value), $temp2);
} else
array_unshift($temp, $value);
}
return implode('', $temp);
}
}
// "It says this site is copyrighted just from 2001" (in Hebrew)
$str = "כתוב שהאתר הזה מוגן בזכויות יוצרים רק מאז 2001";
// Reverse everything
$str_blind_reverse = utf8_strrev($str, true);
// Reverse everything but don't change the year 2001 to 1002...
$str_logical_reverse = utf8_strrev($str, false);
carmel.alex at gmail.com
28-Feb-2006 09:54
28-Feb-2006 09:54
This function support utf-8 encoding
function utf8_strrev($str){
preg_match_all('/./us', $str, $ar);
return join('',array_reverse($ar[0]));
}
tex at i18nguy dot com
23-Aug-2005 06:36
23-Aug-2005 06:36
Just a correction to the previous commenter. In ISO 8859-15, the Euro is 0xA4 (164 decimal). It is a 1 byte character.
MagicalTux at FF dot st
12-May-2005 03:20
12-May-2005 03:20
I will make Screend at hf dot webex dot com's comment more clear and understandable.
strrev only works for singlebyte character-sets. Multibytes charactersets are not compatibles with strrev.
US-ASCII and ISO-8859-1 are compatible with strrev, however BIG5, SJIS, UTF-8 aren't.
Despite what you can think, ISO-8859-15 *is* multibyte (the euro symbol - - is coded on two bytes).
There's no mb_strrev function in PHP, so you can't strrev() a multibyte string. Try to convert it to something else with iconv() if it can be represented in a singlebyte character set.
avarab at gmail dot com
07-May-2005 09:53
07-May-2005 09:53
strrev() can be very useful in cases where it makes more sense to do something from the end of a string rather than the beginning (well duh!) such as apply certain regular expressions. Here's a small function to add commas to numbers that works in such a way.
<?php
echo commafy("1500000.1254"); // prints 1,500,000.1254
function commafy($_) {
return strrev( (string)preg_replace( '/(\d{3})(?=\d)(?!\d*\.)/', '$1,' , strrev( $_ ) ) );
}
?>
I originally wrote it in Perl, does it show? ;=)
Screend at hf dot webex dot com
31-Mar-2004 06:17
31-Mar-2004 06:17
this function can only reverse the 1-byte words,like english,it seems,using
<?php
$str=strrev("");
echo $str;
?>
do not get a right result.
but,you can change 2-bytes characters into a ASCLL,the converse it.