Strings
PHP Manual

trim

(PHP 4, PHP 5)

trim — Strip whitespace (or other characters) from the beginning and end of a string

说明

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

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

参数

str

The string that will be trimmed.

charlist

Optionally, the stripped characters can also be specified using the charlist parameter. Simply list all characters that you want to be stripped. With .. you can specify a range of characters.

返回值

The trimmed string.

更新日志

版本 说明
4.1.0 The optional charlist parameter was added.

范例

Example#1 Usage example of trim()

<?php

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

print "\n";

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

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

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

// trim the ASCII control characters at the beginning and end of $binary
// (from 0 to 31 inclusive)
$clean = trim($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(28) "These are a few words :) ..."
string(24) "These are a few words :)"
string(5) "o Wor"
string(14) "Example string"

Example#2 Trimming array values with trim()

<?php
function trim_value(&$value) 
{ 
    $value = trim($value); 
}

$fruit = array('apple','banana ', ' cranberry ');
var_dump($fruit);

array_walk($fruit, 'trim_value');
var_dump($fruit);

?>

上例将输出：

array(3) {
  [0]=>
  string(5) "apple"
  [1]=>
  string(7) "banana "
  [2]=>
  string(11) " cranberry "
}
array(3) {
  [0]=>
  string(5) "apple"
  [1]=>
  string(6) "banana"
  [2]=>
  string(9) "cranberry"
}

参见

Strings
PHP Manual