substr
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String Functions
PHP Manual

# trim

(PHP 4, PHP 5)

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

### Description

string trim ( string `$str` [, string `$character_mask` = " \t\n\r\0\x0B" ] )

This function returns a string with whitespace stripped from the beginning and end of `str`. Without the second parameter, trim() 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.

### Parameters

`str`

  The string that will be trimmed.

`character_mask`

  Optionally, the stripped characters can also be specified using the `character_mask` parameter. Simply list all characters that you want to be stripped. With .. you can specify a 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() - Strip whitespace (or other characters) from the beginning of a string
- rtrim() - Strip whitespace (or other characters) from the end of a string
- str_replace() - Replace all occurrences of the search string with the replacement string

substr
ucfirst
String Functions
PHP Manual