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

Descrierea

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

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.

Parametri

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.

Valorile întoarse

The trimmed string.

Exemple

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);

?>

Exemplul de mai sus va afișa:

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);

?>

Exemplul de mai sus va afișa:

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"
}

Note

Notă: 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.

A se vedea și

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