trim

    (PHP 4, PHP 5, PHP 7, PHP 8)

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

    Опис

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

    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 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.
    • "\v" (ASCII 11 (0x0B)), a vertical tab.

    Параметри

    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.

    Значення, що повертаються

    The trimmed string.

    Приклади

    Приклад #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);

    ?>

    Поданий вище приклад виведе:

    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"

    Приклад #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);

    ?>

    Поданий вище приклад виведе:

    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"
}

    Примітки

    Зауваження: 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.

    Прогляньте також

    • 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

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    User Contributed Notes 2 notes

    up
    11
    pcoates at yukon1000 dot com
    1 year ago
    note there is a behaviour change in php 8

    You used to be able to say:
    $p1 = trim($_POST['p1']);
    This will now throw deprecated warnings if parameter p1 is not set. It is better to say:
    $p1 = trim($_POST['p1']??'');
    or
    $p1 = isset($_POST['p1']) ? trim($_POST['p1']) : null;
    or
    $p1 = isset($_POST['p1']) ? trim($_POST['p1']) : '';
    up
    3
    gwyneth dot llewelyn at gwynethllewelyn dot net
    1 year ago
    Note that trim() is not aware of Unicode points that represent whitespace (e.g., in the General Punctuation block), except, of course, for the ones mentioned in this page.

    There is no Unicode-specific trim function in PHP at the time of writing (July 2023), but you can try some examples of trims using multibyte strings posted on the comments for the mbstring extension: https://www.php.net/manual/en/ref.mbstring.php
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