PHP 7.0.6 Released

    trim

    (PHP 4, PHP 5, PHP 7)

    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

    User Contributed Notes

    ludko2 at gmail dot com
    5 years ago
    Non-breaking spaces can be troublesome with trim:

    <?php
    // turn some HTML with non-breaking spaces into a "normal" string
    $myHTML = "&nbsp;abc";
    $converted = strtr($myHTML, array_flip(get_html_translation_table(HTML_ENTITIES, ENT_QUOTES)));

    // this WILL NOT work as expected
    // $converted will still appear as " abc" in view source
    // (but not in od -x)
    $converted = trim($converted);

    // &nbsp; are translated to 0xA0, so use:
    $converted = trim($converted, "\xA0"); // <- THIS DOES NOT WORK

    // EDITED>>
    // UTF encodes it as chr(0xC2).chr(0xA0)
    $converted = trim($converted,chr(0xC2).chr(0xA0)); // should work

    // PS: Thanks to John for saving my sanity!
    ?>
    Piopier
    9 years ago
    It may be useful to know that trim() returns an empty string when the argument is an unset/null variable.
    jubi at irc dot pl
    12 years ago
    To remove multiple occurences of whitespace characters in a string an convert them all into single spaces, use this:

    <?

    $text = preg_replace('/\s+/', ' ', $text);

    ?>

    ------------
    JUBI
    http://www.jubi.buum.pl
    Hayley Watson
    11 years ago
    Another way to trim all the elements of an array
    <?php
    $newarray     = array_map('trim', $array);
    ?>
    jianglong at qiyi dot com
    11 months ago
    Trim full width space will return mess character,  when target string starts with '《'

    @example 
    echo trim("《", "　");

    @return
    �

    php version 5.4.27

    [EDIT by cmb AT php DOT net: it is not necessarily safe to use trim with multibyte character encodings. The given example is equivalent to echo trim("\xe3\80\8a", "\xe3\x80\x80").]
    dik_allison at msn dot com
    9 months ago
    Just for reference, using trim on a string which only contains blank characters returns an empty string, not ' '.
    i.e. strlen(trim('    ')) is 0
    tomdudman at gmail dot com
    2 years ago
    This function trims regular expressions from strings.

    <?php
            function preg_trim( $string, $pattern ) {
                $pattern = array( "/^" . $pattern . "*/", "/" . $pattern . "*$/" );
            return     preg_replace( $pattern, "", $string );
        }
    ?>

    The following example outputs "Hello, world":

    <?php
        $hello     = "   ...%20Hello, world!";
        echo     preg_trim( $hello, "[^a-zA-Z]" );
    ?>
    tbm.at.home.dot.nl
    14 years ago
    Windows uses two characters for definining newlines, namely ASCII 13 (carriage return, "\r") and ASCII 10 (line feed, "\n") aka CRLF. So if you have a string with CRLF's, trim() won't recognize them as being one newline. To solve this you can use str_replace() to replace the CRLF's with with a space or something.

    <?php
    // string with bunch of CRLF's
    $my_string = "Liquid\r\nTension Experiment\r\n\r\n\r\n";

    // replace CRLF's with spaces
    $my_wonderful_string = str_replace("\r\n", " ", $my_string);
    // would result in "Liquid Tension Experiment   "

    // or just delete the CRLF's (by replacing them with nothing)
    $my_wonderful_string = str_replace("\r\n", "", $my_string);
    // would result in "LiquidTension Experiment"
    ?>
    seyednaser at gmail dot com
    3 years ago
    To show off the empty positions in a string by means of trim():

    <?php
        $string     = "    Hello World!   ";
        echo     $string;
        echo     " Has : ".strlen($string)." letter(s). One by one according to the following:<br />";
        echo     "<br />".$rightt = strlen(ltrim($string)) - strlen(trim($string))." empty position(s) from right.";
        echo     "<br />".$leftt = strlen(rtrim($string)) - strlen(trim($string))." empty position(s) from left.<br />";
            $length = strlen($string);
        for(    $x = 0; $x < $length; $x++){
            $letter = substr($string, $x, 1);
            if(    $letter <> " ")
                echo     "<br />Position&nbsp;&nbsp; $x ===> &nbsp;&nbsp;".substr($string, $x, 1);
            else
                echo     "<br />Position&nbsp;&nbsp; $x ===> &nbsp;&nbsp; Empty";
        }   
    ?>

    the output is:

    Hello World! Has : 19 letter(s). One by one according to the following:

    3 empty position(s) from right.
    4 empty position(s) from left.

    Position   0 ===>    Empty
    Position   1 ===>    Empty
    Position   2 ===>    Empty
    Position   3 ===>    Empty
    Position   4 ===>   H
    Position   5 ===>   e
    Position   6 ===>   l
    Position   7 ===>   l
    Position   8 ===>   o
    Position   9 ===>    Empty
    Position   10 ===>   W
    Position   11 ===>   o
    Position   12 ===>   r
    Position   13 ===>   l
    Position   14 ===>   d
    Position   15 ===>   !
    Position   16 ===>    Empty
    Position   17 ===>    Empty
    Position   18 ===>    Empty
    josecruz at josecruz dot com dot br
    7 years ago
    A simple function to clear extra white spaces along a string.
    <?php
    function TrimStr($str)
    {
            $str = trim($str);
        for(    $i=0;$i < strlen($str);$i++)
        {

            if(    substr($str, $i, 1) != " ")
            {

                    $ret_str .= trim(substr($str, $i, 1));

            }
            else
            {
                while(    substr($str,$i,1) == " ")
              
                {
                        $i++;
                }
                    $ret_str.= " ";
                    $i--; // ***
                }
        }
        return     $ret_str;
    }
    ?>

    [EDIT BY danbrown AT php DOT net: Contains a fix provided by (info AT deep-soft DOT com) to address the issue where "it deletes the first char after spaces (because of while)."]
    dmr37 at cornell dot edu
    10 years ago
    If you want to check whether something ONLY has whitespaces, use the following:

    <?php

    if (trim($foobar)=='') {
       echo     'The string $foobar only contains whitespace!';
    }

    ?>
    gerjoo at gmail dot com
    4 years ago
    On my application I had several users submit what to me appeared as "empty strings", whereas in fact they were submitting the &shy; character.

    Trim, by default, does not strip this character (Though arguably it should). The following code strips this character from your input:

    <?php

    // As the &shy; character is invisible we'll simply use the ASCII numeric representation, and decode via chr():
    $string = trim($string, chr(173));

    // If you wish to strip all occurences this will work:
    $string = str_replace(chr(173), "", $string);

    ?>

    Gerard
    HW
    12 years ago
    You can combine character ranges and individual characters in trim()'s second argument (ditto for ltrim and rtrim). All of the specified characters and ranges will be used concurrently (i.e., if a character on either end of the string matches any of the specified charaters or character ranges, it will be trimmed). The characters and character ranges can be in any order (except of course that the character ranges need to be specified in increasing order) and may overlap.
    E.g., trim any nongraphical non-ASCII character:
    trim($text,"\x7f..\xff\x0..\x1f");
    syn-attack at devilzc0de dot org
    3 years ago
    I think this is my implementation of trim...

    <?php
            /*
         * Function: "trim"
         * @str = source
         * @charlist = list of characters to be trimmed from the source
         *
         * Author: syn-attack@devilzc0de.org
         * Full documentation in http://php.net/manual/en/function.trim.php
         */
            function __trim($str, $charlist = '') {
                $result = '';
                /* list of forbidden chars to be trimmed */
                $forbidden_list = array(" ", "\t", "\r", "\n", "\0", "\x0B");
           
            if (empty(    $charlist)) {
                for (    $i = 0; $i < strlen($str); $i++) {
                    if ((    $str[$i] != $forbidden_list[0]) &&
                        (    $str[$i] != $forbidden_list[1]) &&
                        (    $str[$i] != $forbidden_list[2]) &&
                        (    $str[$i] != $forbidden_list[3]) &&
                        (    $str[$i] != $forbidden_list[4]) &&
                        (    $str[$i] != $forbidden_list[5])) {
                            $result .= $str[$i];
                    }
                }
            }
            else if (!empty(    $charlist)) {
                    $is_not_same = true;
               
                for (    $i = 0; $i < strlen($str); $i++) {
                    for (    $j = 0; $j < strlen($charlist); $j++) {
                        if (    $str[$i] != $charlist[$j]) {
                                $is_not_same = true;
                        }
                        else if (    $str[$i] == $charlist[$j]) {
                                $is_not_same = false;
                            break;
                        }
                    }
                   
                    if (    $is_not_same == true) {
                            $result .= $str[$i];
                    }
                }
            }
           
            return (    $result);
        }
       
            $str = "Paulus Gandung Prakosa";
        echo     __trim($str);
    ?>
    david at rayninfo dot co dot uk
    1 year ago
    Trim will generate a warning is you try to trim an empty string if this is a problem for you can test with is_string
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