String Functions
PHP Manual

trim

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

Description

string trim(string $string, string $characters = " \n\r\t\v\x00")

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

  • " ": ASCII SP character 0x20, an ordinary space.
  • "\t": ASCII HT character 0x09, a tab.
  • "\n": ASCII LF character 0x0A, a new line (line feed).
  • "\r": ASCII CR character 0x0D, a carriage return.
  • "\0": ASCII NUL character 0x00, the NUL-byte.
  • "\v": ASCII VT character 0x0B, a vertical tab.

Parameters

string

The string that will be trimmed.

characters
Optionally, the stripped characters can also be specified using the characters parameter. Simply list all characters that need to be stripped. With .. it is possible to specify an incrementing range of characters.

Return Values

The trimmed string.

Examples

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);

$trimmed = trim($hello, 'HdWr');
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);

?>

The above example will output:

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(9) "ello Worl"
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);

?>

The above example will output:

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"
}

Notes

Note: Possible gotcha: removing middle characters

Because trim trims characters from the beginning and end of a string, it may be confusing when characters are (or are not) removed from the middle. trim('abc', 'bad') removes both 'a' and 'b' because it trims 'a' thus moving 'b' to the beginning to also be trimmed. So, this is why it "works" whereas trim('abc', 'b') seemingly does not.

See Also

  • ltrim
  • rtrim
  • str_replace