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# rtrim

(PHP 3, PHP 4, PHP 5)

rtrim -- Strip whitespace (or other characters) from the end of a string

## Description

string rtrim ( string str [, string charlist] )

> 注意: The second parameter was added in PHP 4.1.0

This function returns a string with whitespace stripped from the end of `str`. Without the second parameter, rtrim() will strip these characters:

- " " (ASCII `32` (`0x20`)), an ordinary space.

- "\t" (ASCII `9` (`0x09`)), a tab.

- "\n" (ASCII `10` (`0x0A`)), a new line (line feed).

- "\r" (ASCII `13` (`0x0D`)), a carriage return.

- "\0" (ASCII `0` (`0x00`)), the `NUL`-byte.

- "\x0B" (ASCII `11` (`0x0B`)), a vertical tab.

You can also specify the characters you want to strip, by means of the `charlist` parameter. Simply list all characters that you want to be stripped. With `..` you can specify a range of characters.

例 1. Usage example of rtrim()

`<?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);
// trim the ASCII control characters at the end of $binary
// (from 0 to 31 inclusive)
$clean = rtrim($binary, "\x00..\x1F");
var_dump($clean);
?>`

上例将输出：

    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"

See also trim() and ltrim().

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