字符串函数
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rtrim

(PHP 4, PHP 5)

rtrim — 删除字符串末端的空白字符（或者其他字符）

说明

string rtrim ( string $str [, string $charlist ] )

该函数删除 str 末端的空白字符并返回。

不使用第二个参数，rtrim() 仅删除以下字符：

参数

str

输入字符串。

charlist

通过指定 charlist，可以指定想要删除的字符列表。简单地列出你想要删除的全部字符。使用 .. 格式，可以指定一个范围。

返回值

返回改变后的字符串。

更新日志

版本 说明
4.1.0 新增 charlist 参数。

范例

Example #1 rtrim() 使用范例

<?php

$text = "\t\tThese are a few words :) ...  ";
$binary = "\x09Example string\x0A";
$hello  = "Hello World";
var_dump($text, $binary, $hello);

print "\n";

$trimmed = rtrim($text);
var_dump($trimmed);

$trimmed = rtrim($text, " \t.");
var_dump($trimmed);

$trimmed = rtrim($hello, "Hdle");
var_dump($trimmed);

// 删除 $binary 末端的 ASCII 码控制字符
// (包括 0 - 31)
$clean = rtrim($binary, "\x00..\x1F");
var_dump($clean);

?>

以上例程会输出：

string(32) "        These are a few words :) ...  "
string(16) "    Example string
"
string(11) "Hello World"

string(30) "        These are a few words :) ..."
string(26) "        These are a few words :)"
string(9) "Hello Wor"
string(15) "    Example string"

参见

字符串函数
在线手册：中文 英文
PHP手册
PHP手册 - N: 删除字符串末端的空白字符（或者其他字符）

用户评论:

NBS Studio (22-Feb-2010 01:02)

The simplest way to strip a newline form a text file is ltrim();

trim or explode or split ("\n" or "\r\n") doesn't work in all cases, so give ltrim(); a try instead.

info at nbs-studio dot com (22-Feb-2010 01:02)

The simplest way to strip a newline form a text file is ltrim();

trim or explode or split ("\n" or "\r\n") doesn't work in all cases, so give ltrim(); a try instead.

pinkgothic at gmail dot com (22-Jan-2010 01:36)

I have an obsessive love for php's array functions given how extremely easy they've made complex string handling for me in various situations... so, have another string-rtrim() variant:

<?php

function strrtrim($message, $strip) {
    // break message apart by strip string
    $lines = explode($strip, $message);
    $last  = '';
    // pop off empty strings at the end
    do {
        $last = array_pop($lines);
    } while (empty($last) && (count($lines)));
    // re-assemble what remains
    return implode($strip, array_merge($lines, array($last)));
}

?>

Astonishingly, something I didn't expect, but: It completely compares to harmor's rstrtrim below, execution time wise. o_o Whee!

harmor (04-Apr-2008 11:05)

I'm sure there's a better way to strip strings from the end of strings.

<?php
/**
 * Strip a string from the end of a string
 *
 * @param string $str      the input string
 * @param string $remove   OPTIONAL string to remove
 * 
 * @return string the modified string
  */
function rstrtrim($str, $remove=null)
{
    $str    = (string)$str;
    $remove = (string)$remove;   
   
    if(empty($remove))
    {
        return rtrim($str);
    }
   
    $len = strlen($remove);
    $offset = strlen($str)-$len;
    while($offset > 0 && $offset == strpos($str, $remove, $offset))
    {
        $str = substr($str, 0, $offset);
        $offset = strlen($str)-$len;
    }
   
    return rtrim($str);   
   
} //End of function rstrtrim($str, $remove=null)

echo rstrtrim('Hello World!!!', '!')   .'<br />'; //"Hello World"
echo rstrtrim('Hello World!!!', '!!')  .'<br />'; //"Hello World!"
echo rstrtrim('Hello World!!!', '!!!') .'<br />'; //"Hello World"
echo rstrtrim('Hello World!!!', '!!!!').'<br />'; //"Hello World!!!"
?>

YAS (08-May-2006 02:01)

To remove an unwanted character - example "." - if exist or not.

The example above doesn't include the case where there is no "."
If there is not "." at the example above the last word will be deleted.

Have fun with this code.

<?php
$text = "This string contains. some unwanted characters on the end .";
$text = trim($text);
$last = $text{strlen($text)-1};
if (!strcmp($last,"."))
{
  $text = rtrim($text, 'a..z');
  $text = rtrim($text, '.');
}
?>

gbelanger at exosecurity dot com (17-Feb-2006 10:31)

True, the Perl chomp() will only trim newline characters. There is, however, the Perl chop() function which is pretty much identical to the PHP rtrim()

---

Here's a quick way to recursively trim every element of an array, useful after the file() function :

<?php
# Reads /etc/passwd file an trims newlines on each entry
$aFileContent = file("/etc/passwd");
foreach ($aFileContent as $sKey => $sValue) {
    $aFileContent[$sKey] = rtrim($sValue);
}

print_r($aFileContent);
?>

Unimagined at UnaimaginedDesigns dot Com (16-Jan-2005 08:49)

I needed a way to trim all white space and then a few chosen strings from the end of a string.  So I wrote this class to reuse when stuff needs to be trimmed. 

<?php

class cleaner {

function cleaner ($cuts,$pinfo) {
$ucut = "0";
$lcut = "0";
while ($cuts[$ucut]) {
$lcut++;
$ucut++;
}
$lcut = $lcut - 1;
$ucut = "0";
$rcut = "0";
$wiy = "start";

while ($wiy) {

if ($so) {
$ucut = "0";
$rcut = "0";
unset($so);
}

if (!$cuts[$ucut]) {
$so = "restart";
} else {
$pinfo = rtrim($pinfo);
$bpinfol = strlen($pinfo);
$tcut = $cuts[$ucut];
$pinfo = rtrim($pinfo,"$tcut");
$pinfol = strlen($pinfo);

    if ($bpinfol == $pinfol) {
    $rcut++;
    if ($rcut == $lcut) {
    unset($wiy);
    }
    $ucut++;
    } else {
    $so = "restart";
    }
}
}

$this->cleaner = $pinfo;
}

}

$pinfo = "Well... I'm really bored...<br /><br>&nbsp;    \n\t&nbsp;<br><br /><br>&nbsp;    \r\r&nbsp;<br>\r<br /><br>\r&nbsp;    &nbsp;\n<br>      <br />\t";

$cuts = array('\n','\r','\t',' ',' ','&nbsp;','<br />','<br>','<br/>');

$pinfo = new cleaner($cuts,$pinfo);
$pinfo = $pinfo->cleaner;

print $pinfo;

?>

That class will take any string that you put in the $cust array and remove it from the end of the $pinfo string.  It's useful for cleaning up comments, articles, or mail that users post to your site, making it so there's no extra blank space or blank lines.

todd at magnifisites dot com (20-Aug-2003 02:19)

This shows how rtrim works when using the optional charlist parameter:
rtrim reads a character, one at a time, from the optional charlist parameter and compares it to the end of the str string. If the characters match, it trims it off and starts over again, looking at the "new" last character in the str string and compares it to the first character in the charlist again. If the characters do not match, it moves to the next character in the charlist parameter comparing once again. It continues until the charlist parameter has been completely processed, one at a time, and the str string no longer contains any matches. The newly "rtrimmed" string is returned.
<?php
  // Example 1:
  rtrim('This is a short short sentence', 'short sentence');
  // returns 'This is a'
  // If you were expecting the result to be 'This is a short ',
  // then you're wrong; the exact string, 'short sentence',
  // isn't matched.  Remember, character-by-character comparison!
  // Example 2:
  rtrim('This is a short short sentence', 'cents');
  // returns 'This is a short short '
?>

HW (06-Jun-2003 02:32)

<?php
$text = "This string contains some unwanted characters on the end.";
$text1 = rtrim($text, 'a..z');
$text1 = rtrim($text1, '.');
echo $text1; // only the '.' is trimmed.
$text2 = rtrim($text, 'a..z.');
echo $text2; // The whole last word is trimmed.
?>