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    substr

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

    substr — 文字列の一部分を返す

    説明

    substr(string $string, int $offset, ?int $length = null): string

    文字列 string の、offset で指定された位置から length バイト分の文字列を返します。

    パラメータ

    string

    入力文字列。

    offset

    offset が正の場合、返される文字列は、 string の 0 から数えて offset番目から始まる文字列となります。 例えば、文字列'abcdef'において位置 0にある文字は、'a'であり、 位置2には'c'があります。

    offset が負の場合、返される文字列は、 stringの後ろから数えて offset番目から始まる文字列となります。

    string の長さが offset 文字より短い場合は、 空の文字列が返されます。

    例1 負の offset の使用

    <?php
    $rest     = substr("abcdef", -1); // "f" を返す
    $rest = substr("abcdef", -2); // "ef" を返す
    $rest = substr("abcdef", -3, 1); // "d" を返す
    ?>

    length

    length が指定され、かつ正である場合、 返される文字列は offset (string の長さに依存します) から数えてlength文字数分となります。

    length が指定され、かつ負である場合、 string の終端からその文字数分の文字が省略されます (offset が負の場合は、 開始位置を算出したあとで)。 もし offset が切り出し位置を超える場合、 空の文字列が返されます。

    length が指定され、かつ 0 であれば、空の文字が返されます。

    length を省略した場合、または null の場合は、 offset の位置から文字列の最後までの部分文字列を返します。

    例2 負の length の使用

    <?php
    $rest     = substr("abcdef", 0, -1); // "abcde" を返す
    $rest = substr("abcdef", 2, -1); // "cde" を返す
    $rest = substr("abcdef", 4, -4); // "" を返す。PHP 8.0.0 より前のバージョンでは、false を返していました。
    $rest = substr("abcdef", -3, -1); // "de" を返す
    ?>

    戻り値

    string の一部を返すか、空文字列を返します。

    変更履歴

    バージョン 説明
    8.0.0 length は、nullable になりました。 length に明示的に null を設定すると、 文字列の最後までを含む部分文字列を返すようになっています。 これより前のバージョンでは、空文字列を返していました。
    8.0.0 この関数は、前のバージョンで false を返す場合に、空文字列を返すようになりました。

    例

    例3 基本的な substr() の使用法

    <?php
    echo substr('abcdef', 1); // bcdef
    echo substr("abcdef", 1, null); // bcdef, PHP 8.0.0 より前のバージョンでは、空の文字列を返していました。
    echo substr('abcdef', 1, 3); // bcd
    echo substr('abcdef', 0, 4); // abcd
    echo substr('abcdef', 0, 8); // abcdef
    echo substr('abcdef', -1, 1); // f

    // 文字列中の 1 文字にアクセスすることも
    // "角括弧" を使用することで可能
    $string = 'abcdef';
    echo     $string[0]; // a
    echo $string[3]; // d
    echo $string[strlen($string)-1]; // f

    ?>

    例4 substr() でのキャストの挙動

    <?php
    class apple {
    public function     __toString() {
    return     "green";
    }
    }

    echo     "1) ".var_export(substr("pear", 0, 2), true).PHP_EOL;
    echo     "2) ".var_export(substr(54321, 0, 2), true).PHP_EOL;
    echo     "3) ".var_export(substr(new apple(), 0, 2), true).PHP_EOL;
    echo     "4) ".var_export(substr(true, 0, 1), true).PHP_EOL;
    echo     "5) ".var_export(substr(false, 0, 1), true).PHP_EOL;
    echo     "6) ".var_export(substr("", 0, 1), true).PHP_EOL;
    echo     "7) ".var_export(substr(1.2e3, 0, 4), true).PHP_EOL;
    ?>

    上の例の出力は以下となります。

    1) 'pe'
2) '54'
3) 'gr'
4) '1'
5) ''
6) ''
7) '1200'

    例5 文字列の範囲が不正な場合

    指定された文字列の範囲が正しくない場合、 substr() は PHP 8.0.0 以降では空文字列を返します。 それより前のバージョンでは、false を返していました。

    <?php
    var_dump    (substr('a', 2));
    ?>

    上の例の PHP 8 での出力は、このようになります。:

    string(0) ""

    上の例の PHP 7 での出力は、このようになります。

    bool(false)

    参考

    add a note add a note

    User Contributed Notes 36 notes

    up
    168
    Andreas Bur (andreas dot buro at gmail dot com)
    15 years ago
    For getting a substring of UTF-8 characters, I highly recommend mb_substr

    <?php
            $utf8string     = "cakeæøå";

            echo     substr($utf8string,0,5);
                // output cake#
                echo mb_substr($utf8string,0,5,'UTF-8');
                //output cakeæ
    ?>
    up
    123
    biohazard dot ge at gmail dot com
    11 years ago
    may be by following functions will be easier to extract the needed sub parts from a string:

    <?php
    after     ('@', 'biohazard@online.ge');
    //returns 'online.ge'
    //from the first occurrence of '@'

    before ('@', 'biohazard@online.ge');
    //returns 'biohazard'
    //from the first occurrence of '@'

    between ('@', '.', 'biohazard@online.ge');
    //returns 'online'
    //from the first occurrence of '@'

    after_last ('[', 'sin[90]*cos[180]');
    //returns '180]'
    //from the last occurrence of '['

    before_last ('[', 'sin[90]*cos[180]');
    //returns 'sin[90]*cos['
    //from the last occurrence of '['

    between_last ('[', ']', 'sin[90]*cos[180]');
    //returns '180'
    //from the last occurrence of '['
    ?>

    here comes the source:

    <?php

            function after ($this, $inthat)
        {
            if (!    is_bool(strpos($inthat, $this)))
            return     substr($inthat, strpos($inthat,$this)+strlen($this));
        };

        function     after_last ($this, $inthat)
        {
            if (!    is_bool(strrevpos($inthat, $this)))
            return     substr($inthat, strrevpos($inthat, $this)+strlen($this));
        };

        function     before ($this, $inthat)
        {
            return     substr($inthat, 0, strpos($inthat, $this));
        };

        function     before_last ($this, $inthat)
        {
            return     substr($inthat, 0, strrevpos($inthat, $this));
        };

        function     between ($this, $that, $inthat)
        {
            return     before ($that, after($this, $inthat));
        };

        function     between_last ($this, $that, $inthat)
        {
         return     after_last($this, before_last($that, $inthat));
        };

    // use strrevpos function in case your php version does not include it
    function strrevpos($instr, $needle)
    {
            $rev_pos = strpos (strrev($instr), strrev($needle));
        if (    $rev_pos===false) return false;
        else return     strlen($instr) - $rev_pos - strlen($needle);
    };
    ?>
    up
    4
    Anonymous
    7 years ago
    Be aware of a slight inconsistency between substr and mb_substr

    mb_substr("", 4);      returns empty string

    substr("", 4);              returns boolean false

    tested in PHP 7.1.11 (Fedora 26) and PHP 5.4.16 (CentOS 7.4)
    up
    15
    pugazhenthi k
    11 years ago
    <?Php

    ### SUB STRING  BY WORD USING substr() and strpos()  #####

    ### THIS SCRIPT WILL RETURN PART OF STRING  WITHOUT WORD BREAK ###

    $description = ‘your description here your description here your description here your description here your description here your description here your description hereyour description here your description here’  // your description here .

    $no_letter = 30 ;

    if(    strlen($desctiption) > 30 )
    {
         echo     substr($description,0,strpos($description,’ ‘,30));             //strpos to find ‘ ‘ after 30 characters.
    }
    else {
         echo     $description;
    }

    ?>
    up
    10
    greg at apparel dot com
    11 years ago
    Coming to PHP from classic ASP I am used to the Left() and Right() functions built into ASP so I did a quick PHPversion. hope these help someone else making the switch

    function left($str, $length) {
        return substr($str, 0, $length);
    }

    function right($str, $length) {
        return substr($str, -$length);
    }
    up
    6
    nikolai dot wuestemann at t-online dot de
    13 years ago
    If you want to have a string BETWEEN two strings, just use this function:

    <?php
    function get_between($input, $start, $end)
    {
          $substr = substr($input, strlen($start)+strpos($input, $start), (strlen($input) - strpos($input, $end))*(-1));
      return     $substr;
    }

    //Example:

    $string = "123456789";
    $a = "12";
    $b = "9";

    echo     get_between($string, $a, $b);

    //Output:
    //345678
    ?>
    up
    4
    bleakwind at msn dot com
    19 years ago
    This returns the portion of str specified by the start and length parameters..
    It can performs multi-byte safe on number of characters. like mb_strcut() ...

    Note:
    1.Use it like this bite_str(string str, int start, int length [,byte of on string]);
    2.First character's position is 0. Second character position is 1, and so on...
    3.$byte is one character length of your encoding, For example: utf-8 is "3", gb2312 and big5 is "2"...you can use the function strlen() get it...
    Enjoy it :) ...

    --- Bleakwind
    QQ:940641
    http://www.weaverdream.com

    PS:I'm sorry my english is too poor... :(

    <?php
    // String intercept By Bleakwind
    // utf-8:$byte=3 | gb2312:$byte=2 | big5:$byte=2
    function bite_str($string, $start, $len, $byte=3)
    {
            $str     = "";
            $count   = 0;
            $str_len = strlen($string);
        for (    $i=0; $i<$str_len; $i++) {
            if ((    $count+1-$start)>$len) {
                    $str  .= "...";
                break;
            } elseif ((    ord(substr($string,$i,1)) <= 128) && ($count < $start)) {
                    $count++;
            } elseif ((    ord(substr($string,$i,1)) > 128) && ($count < $start)) {
                    $count = $count+2;
                    $i     = $i+$byte-1;
            } elseif ((    ord(substr($string,$i,1)) <= 128) && ($count >= $start)) {
                    $str  .= substr($string,$i,1);
                    $count++;
            } elseif ((    ord(substr($string,$i,1)) > 128) && ($count >= $start)) {
                    $str  .= substr($string,$i,$byte);
                    $count = $count+2;
                    $i     = $i+$byte-1;
            }
        }
        return     $str;
    }

    // Test
    $str = "123456???ֽ?123456?ַ???123456??ȡ????";
    for(    $i=0;$i<30;$i++){
        echo     "<br>".bite_str($str,$i,20);   
    }
    ?>
    up
    5
    fatihmertdogancan at hotmail dot com
    10 years ago
    [English]
    I created python similar accesing list or string with php substr & strrev functions.

    Use: str($string,$pattern)

    About the python pattern,
    http://docs.python.org/release/1.5.1p1/tut/strings.html
    http://effbot.org/zone/python-list.htm

    About of pattern structures
    [start:stop:step]

    Example,
    <?php
    $s     = "fatihmertdogancan";
    echo     str($s,"1:9:-2");
    echo     "<br/>";
    echo     str($s,"1:-3:-2");
    echo     "<br/>";
    echo     str($s,"1:-11:-5");
    echo     "<br/>";
    echo     str($s,"1:9:4");
    ?>

    Output,
    thetoacn
    eht
    aom
    htan

    This is function phpfiddle link: http://phpfiddle.org/main/code/e82-y5d

    or source;

    <?php
            function str($str,$pattern){
                //[start:stop:step]
            //pattern ->            ([-]?[0-9]*|\s):([-]?[0-9]*|\s):([-]?[0-9]*|\s)
                preg_match("/([-]?[0-9]*|\s?):([-]?[0-9]*|\s?):?([-]?[0-9]*|\s?)/", $pattern, $yakala);
                $start = $yakala[1];
                $stop = $yakala[2];
                $step = $yakala[3];
           
            if(empty(    $start) && empty($stop) && $step == "-1"){//istisna durum
                    return strrev($str);
            }else if(empty(    $start) && empty($stop) && isset($step)){//istisna durum
                    $rev = "";
                    $yeni = "";
                if(    $step[0] == "-" && $stop != "-1"){$rev = "VAR";}
                    $atla = abs($step);
                for(    $i = 0; $i <= strlen($str); $i++){
                        $offset = $i*$atla;
                    if(isset(    $str[$offset])){
                            $yeni = $yeni.$str[$offset];
                    }
                }
                if(    $rev != "VAR"){
                    return     substr($yeni,0,strlen($str)-1);
                        //"hepsi boş, step dolu o da +";
                    }else{
                    return     strrev(substr($yeni,0,strlen($str)-1));
                        //"hepsi boş, step dolu o da -";
                    }
            }
           
            if(empty(    $start) && empty($stop) && empty($step)){
                return     $str;
                    //"hepsi boş";
                }else if(empty($start)){
                if(isset(    $stop) && empty($step)){
                        $rev = "";
                    if(    $stop[0] == "-"){$rev = "VAR";}
                    if(    $rev != "VAR"){
                        return     substr($str,0,$stop);
                            //"start ve step boş, stop dolu"
                        }else{
                        return     strrev(substr($str,0,$stop));
                            //"start ve step boş, stop -1";
                        }
                }else if(isset(    $stop) && isset($step)){
                        $rev = "";
                    if(    $stop[0] == "-"){$rev = "VAR";}
                        $yeni = "";
                    if(    $step == 1){
                        if(    $rev != "VAR"){
                            return     $str;
                                //"start boş, stop ve step dolu, step 1";
                            }else{
                            return     strrev(substr($str,0,abs($stop))); //abs -> mutlak değer (-5 = 5)
                            //"start boş, stop -, step dolu, step 1";
                            }
                    }else{
                            $atla = abs($step);
                        for(    $i = 0; $i <= strlen($str); $i++){
                                $offset = $i*$atla;
                            if(isset(    $str[$offset])){
                                    $yeni = $yeni.$str[$offset];
                            }
                        }
                        if(    $rev != "VAR"){
                            return     substr($yeni,0,$stop);
                                //"start boş, step ve stop dolu";
                            }else{
                            return     strrev(substr($yeni,0,abs($stop)));
                                //"start boş, step ve stop -";
                            }
                    }
                }
                //start boş değilse
                }else if(!empty($start)){
                if(isset(    $stop) && empty($step)){
                        $rev = "";
                    if(    $stop[0] == "-"){$rev = "VAR";}
                    if(    $rev != "VAR"){
                        return     substr($str,$start,$stop);
                            //return "step boş, start ve stop dolu";
                        }else{
                        return     strrev(substr($str,0,abs($stop)));
                            //"step boş, start ve stop dolu, stop -";
                        }
                }else if(isset(    $stop) && isset($step)){
                   
                        //hepsi dolu
                        $rev = "";
                    if(    $stop[0] == "-"){$rev = "VAR";}
                        $yeni = "";
                    if(    $step == 1){
                        if(    $rev != "VAR"){
                            return     substr($str,$start,$stop);
                                //"hepsi dolu, step 1";
                            }else{
                            return     substr($str,$start,abs($stop));
                                //"hepsi dolu, step 1, stop -";
                            }
                    }else{
                        if(    $stop[0] == "-"){$rev = "VAR";}
                            $atla = abs($step);
                        for(    $i = 0; $i <= strlen($str); $i++){
                                $offset = $i*$atla;
                            if(isset(    $str[$offset])){
                                    $yeni = $yeni.$str[$offset];
                            }
                        }
                        if(    $rev != "VAR"){
                            return     substr($yeni,$start,$stop);
                                //"hepsi dolu";
                            }else{
                            return     strrev(substr($yeni,$start,abs($stop)));
                                //"hepsi dolu, stop -";
                            }
                    }
                }
            }
        }
    ?>

    Good works..
    up
    3
    kaysar in ymail in com
    15 years ago
    Drop extensions of a file (even from a file location string)

    <?php

    $filename     = "c:/some dir/abc defg. hi.jklmn";

    echo     substr($filename, 0, (strlen ($filename)) - (strlen (strrchr($filename,'.'))));

    ?>

    output: c:/some dir/abc defg. hi

    Hope it may help somebody like me.. (^_^)
    up
    6
    Petez
    17 years ago
    I wanted to work out the fastest way to get the first few characters from a string, so I ran the following experiment to compare substr, direct string access and strstr:

    <?php
    /* substr access */
    beginTimer();
    for (    $i = 0; $i < 1500000; $i++){
            $opening = substr($string,0,11);
        if (    $opening == 'Lorem ipsum'){
                true;
        }else{
                false;
        }
    }
    $endtime1 = endTimer();

    /* direct access */
    beginTimer();
    for (    $i = 0; $i < 1500000; $i++){
        if (    $string[0] == 'L' && $string[1] == 'o' && $string[2] == 'r' && $string[3] == 'e' && $string[4] == 'm' && $string[5] == ' ' && $string[6] == 'i' && $string[7] == 'p' && $string[8] == 's' && $string[9] == 'u' && $string[10] == 'm'){
                true;
        }else{
                false;
        }
    }
    $endtime2 = endTimer();

    /* strstr access */
    beginTimer();
    for (    $i = 0; $i < 1500000; $i++){
            $opening = strstr($string,'Lorem ipsum');
        if (    $opening == true){
                true;
        }else{
                false;
        }
    }
    $endtime3 = endTimer();

    echo     $endtime1."\r\n".$endtime2."\r\n".$endtime3;
    ?>

    The string was 6 paragraphs of Lorem Ipsum, and I was trying match the first two words. The experiment was run 3 times and averaged. The results were:

    (substr) 3.24
    (direct access) 11.49
    (strstr) 4.96

    (With standard deviations 0.01, 0.02 and 0.04)

    THEREFORE substr is the fastest of the three methods for getting the first few letters of a string.
    up
    3
    link
    15 years ago
    I created some functions for entity-safe splitting+lengthcounting:

    <?php
    function strlen_entities($text)
    {
            preg_match_all(
                '/((?:&(?:#[0-9]{2,}|[a-z]{2,});)|(?:[^&])|'.        
                '(?:&(?!\w;)))s',$text,$textarray);
        return     count($textarray[0]);
    } 
    function     substr_entities($text,$start,$limit=0)
    {
            $return = '';
            preg_match_all(
                '/((?:&(?:#[0-9]{2,}|[a-z]{2,});)|(?:[^&])|'.        
                '(?:&(?!\w;)))s',$text,$textarray);
            $textarray = $textarray[0];
            $numchars = count($textarray)-1;
        if (    $start>=$numchars)
            return     false;
        if (    $start<0)
        {
                $start = ($numchars)+$start+1;
        }
        if (    $start>=0)
        {
            if (    $limit==0)
            {
                    $end=$numchars;
            }
            elseif (    $limit>0)
            {
                    $end = $start+($limit-1);
            }
            else
            {
                    $end = ($numchars)+$limit;
            }

            for (    $i=$start;$i<=$end;$i++)
            {
                    $return .= $textarray[$i];
            }
            return     $return;
        }
    }
    ?>
    up
    2
    pheagey at gmail dot com
    12 years ago
    Using a 0 as the last parameter for substr().

    As per examples
    <?php $var = substr($var, 4); ?>

    works no problem. However
    <?php $var = substr($var, 4, 0); ?>

    will get you nothing. Just a quick heads up
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    2
    gkhelloworld at gmail dot com
    15 years ago
    Shortens the filename and its expansion has seen.

    <?php
    $file     = "Hellothisfilehasmorethan30charactersandthisfayl.exe";

    function     funclongwords($file)
    {
    if (    strlen($file) > 30)
    {
    $vartypesf = strrchr($file,".");
    $vartypesf_len = strlen($vartypesf);
    $word_l_w = substr($file,0,15);
    $word_r_w = substr($file,-15);
    $word_r_a = substr($word_r_w,0,-$vartypesf_len);

    return     $word_l_w."...".$word_r_a.$vartypesf;
    }
    else
    return     $file;
    }
    // RETURN: Hellothisfileha...andthisfayl.exe
    ?>
    up
    5
    fanfatal at fanfatal dot pl
    19 years ago
    Hmm ... this is a script I wrote, whitch is very similar to substr, but it isn't takes html and bbcode for counting and it takes portion of string and show avoided (html & bbcode) tags too ;]
    Specially usefull for show part of serach result included html and bbcode tags

    <?php

    /**
    * string csubstr ( string string, int start [, int length] )
    *
    * @author FanFataL
    * @param string string
    * @param int start
    * @param [int length]
    * @return string
    */
    function csubstr($string, $start, $length=false) {
            $pattern = '/(\[\w+[^\]]*?\]|\[\/\w+\]|<\w+[^>]*?>|<\/\w+>)/i';
            $clean = preg_replace($pattern, chr(1), $string);
        if(!    $length)
                $str = substr($clean, $start);
        else {
                $str = substr($clean, $start, $length);
                $str = substr($clean, $start, $length + substr_count($str, chr(1)));
        }
            $pattern = str_replace(chr(1),'(.*?)',preg_quote($str));
        if(    preg_match('/'.$pattern.'/is', $string, $matched))
            return     $matched[0];
        return     $string;
    }

    ?>

    Using this is similar to simple substr.

    Greatings ;]
    ...
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    5
    slow at acedsl dot com
    13 years ago
    Anyone coming from the Python world will be accustomed to making substrings by using a "slice index" on a string.  The following function emulates basic Python string slice behavior. (A more elaborate version could be made to support array input as well as string, and the optional third "step" argument.)

    <?php

    function py_slice($input, $slice) {
            $arg = explode(':', $slice);
            $start = intval($arg[0]);
        if (    $start < 0) {
                $start += strlen($input);
        }
        if (    count($arg) === 1) {
            return     substr($input, $start, 1);
        }
        if (    trim($arg[1]) === '') {
            return     substr($input, $start);
        }
            $end = intval($arg[1]);
        if (    $end < 0) {
                $end += strlen($input);
        }
        return     substr($input, $start, $end - $start);
    }

    print     py_slice('abcdefg', '2') . "\n";
    print     py_slice('abcdefg', '2:4') . "\n";
    print     py_slice('abcdefg', '2:') . "\n";
    print     py_slice('abcdefg', ':4') . "\n";
    print     py_slice('abcdefg', ':-3') . "\n";
    print     py_slice('abcdefg', '-3:') . "\n";

    ?>

    The $slice parameter can be a single character index, or a range separated by a colon. The start of the range is inclusive and the end is exclusive, which may be  counterintuitive. (Eg, py_slice('abcdefg', '2:4') yields 'cd' not 'cde'). A negative range value means to count from the end of the string instead of the beginning. Both the start and end of the range may be omitted; the start defaults to 0 and the end defaults to the total length of the input.

    The output from the examples:
    c
    cd
    cdefg
    abcd
    abcd
    efg
    up
    2
    egingell at sisna dot com
    18 years ago
    <?php

    /**
    * string substrpos(string $str, mixed $start [[, mixed $end], boolean $ignore_case])
    *
    * If $start is a string, substrpos will return the string from the position of the first occuring $start to $end
    *
    * If $end is a string, substrpos will return the string from $start to the position of the first occuring $end
    *
    * If the first character in (string) $start or (string) $end is '-', the last occuring string will be used.
    *
    * If $ignore_case is true, substrpos will not care about the case.
    * If $ignore_case is false (or anything that is not (boolean) true, the function will be case sensitive.
    *        Both of the above: only applies if either $start or $end are strings.
    *
    * echo substrpos('This is a string with 0123456789 numbers in it.', 5, '5');
    *        // Prints 'is a string with 01234';
    *
    * echo substrpos('This is a string with 0123456789 numbers in it.', '5', 5);
    *        // Prints '56789'
    *
    * echo substrpos('This is a string with 0123456789 numbers in it and two strings.', -60, '-string')
    *        // Prints 's is a string with 0123456789 numbers in it and two '
    *
    * echo substrpos('This is a string with 0123456789 numbers in it and two strings.', -60, '-STRING', true)
    *        // Prints 's is a string with 0123456789 numbers in it and two '
    *
    * echo substrpos('This is a string with 0123456789 numbers in it and two strings.', -60, '-STRING', false)
    *        // Prints 's is a string with 0123456789 numbers in it and two strings.'
    *
    * Warnings:
    *        Since $start and $end both take either a string or an integer:
    *            If the character or string you are searching $str for is a number, pass it as a quoted string.
    *        If $end is (integer) 0, an empty string will be returned.
    *        Since this function takes negative strings ('-search_string'):
    *            If the string your using in $start or $end is a '-' or begins with a '-' escape it with a '\'.
    *            This only applies to the *first* character of $start or $end.
    */

    // Define stripos() if not defined (PHP < 5).
    if (!is_callable("stripos")) {
        function     stripos($str, $needle, $offset = 0) {
            return     strpos(strtolower($str), strtolower($needle), $offset);
        }
    }

    function     substrpos($str, $start, $end = false, $ignore_case = false) {
            // Use variable functions
            if ($ignore_case === true) {
                $strpos = 'stripos'; // stripos() is included above in case it's not defined (PHP < 5).
            } else {
                $strpos = 'strpos';
        }

            // If end is false, set it to the length of $str
            if ($end === false) {
                $end = strlen($str);
        }

            // If $start is a string do what's needed to make it an integer position for substr().
            if (is_string($start)) {
                // If $start begins with '-' start processing until there's no more matches and use the last one found.
                if ($start{0} == '-') {
                    // Strip off the '-'
                    $start = substr($start, 1);
                    $found = false;
                    $pos = 0;
                while((    $curr_pos = $strpos($str, $start, $pos)) !== false) {
                        $found = true;
                        $pos = $curr_pos + 1;
                }
                if (    $found === false) {
                        $pos = false;
                } else {
                        $pos -= 1;
                }
            } else {
                    // If $start begins with '\-', strip off the '\'.
                    if ($start{0} . $start{1} == '\-') {
                        $start = substr($start, 1);
                }
                    $pos = $strpos($str, $start);
            }
                $start = $pos !== false ? $pos : 0;
        }

            // Chop the string from $start to strlen($str).
            $str = substr($str, $start);

            // If $end is a string, do exactly what was done to $start, above.
            if (is_string($end)) {
            if (    $end{0} == '-') {
                    $end = substr($end, 1);
                    $found = false;
                    $pos = 0;
                while((    $curr_pos = strpos($str, $end, $pos)) !== false) {
                        $found = true;
                        $pos = $curr_pos + 1;
                }
                if (    $found === false) {
                        $pos = false;
                } else {
                        $pos -= 1;
                }
            } else {
                if (    $end{0} . $end{1} == '\-') {
                        $end = substr($end, 1);
                }
                    $pos = $strpos($str, $end);
            }
                $end = $pos !== false ? $pos : strlen($str);
        }

            // Since $str has already been chopped at $start, we can pass 0 as the new $start for substr()
            return substr($str, 0, $end);
    }

    ?>
    up
    4
    mar dot czapla at gmail dot com
    16 years ago
    Here we have gr8 function which simply convert ip address to a number using substr with negative offset.
    You can need it if you want to compare some IP addresses converted to a numbers.
    For example when using ip2country, or eliminating same range of ip addresses from your website :D

    <?php

    function ip2no($val)
    {   
        list(    $A,$B,$C,$D)    =    explode(".",$val);
        return
                substr("000".$A,-3).
                substr("000".$B,-3).
                substr("000".$C,-3).
                substr("000".$D,-3);
    }

    $min        =    ip2no("10.11.1.0");
    $max        =    ip2no("111.11.1.0");
    $visitor    =    ip2no("105.1.20.200");

    if(    $min<$visitor && $visitor<$max)   
        {    echo     'Welcome !';    }
    else   
        {    echo     'Get out of here !';    }

    ?>
    up
    1
    Quicker
    13 years ago
    If you need to parse utf-8 strings char by char, try this one:

    <?php
         $utf8marker    =chr(128);
             $count=0;
         while(isset(    $string{$count})){
           if(    $string{$count}>=$utf8marker) {
                 $parsechar=substr($string,$count,2);
                 $count+=2;
           } else {
                 $parsechar=$string{$count};
                 $count++;
           }
               /* do what you like with parsechar ... , eg.:*/  echo $parsechar."<BR>\r\n";
         }
    ?>

    - it works without mb_substr
    - it is fast, because it grabs characters based on indexes  when possible and avoids any count and split functions
    up
    1
    php_net at thomas dot trella dot de
    19 years ago
    I needed to cut a string after x chars at a  html converted utf-8 text (for example Japanese text like &#23344;&#35632;&#24368;&#33072;&#27440;&#32591;).
    The problem was, the different length of the signs, so I wrote the following function to handle that.
    Perhaps it helps.

    <?php

    function html_cutstr ($str, $len)
    {
        if (!    preg_match('/\&#[0-9]*;.*/i', $str))
        {
                $rVal = strlen($str, $len);
            break;
        }

            $chars = 0;
            $start = 0;
        for(    $i=0; $i < strlen($str); $i++)
        {
            if (    $chars >= $len)
            break;

                $str_tmp = substr($str, $start, $i-$start);
            if (    preg_match('/\&#[0-9]*;.*/i', $str_tmp))
            {
                    $chars++;
                    $start = $i;
            }
        }
            $rVal = substr($str, 0, $start);
        if (    strlen($str) > $start)
            $rVal .= " ...";
        return     $rVal;
    }
    ?>
    up
    1
    leon weidauer
    13 years ago
    When using a value of a wrong type as second parameter , substr() does not return FALSE but NULL although the docs say, it should return FALSE on error.

    Prior to PHP 5.3, substr() tries to cast the second parameter to int and doesn't throw any errors. Since PHP 5.3 a warning is thrown.
    up
    1
    Cristianlf
    14 years ago
    I needed a function like lpad from oracle, or right from SQL
    then I use this code :

    <?php
    function right($string,$chars)
    {
            $vright = substr($string, strlen($string)-$chars,$chars);
        return     $vright;
       
    }

        echo     right('0r0j4152',4);
    ?>

    Result:
    4152
    ------------------------------------------------
    This function is really simple, I just wanted to share, maybe helps someone out there. 

    regards,
    up
    1
    post [at] jannik - zappe [dot] de
    16 years ago
    Just a little function to cut a string by the wanted amount. Works in both directions.

    <?php
    function cutString($str, $amount = 1, $dir = "right")
    {
      if((    $n = strlen($str)) > 0)
      {
        if(    $dir == "right")
        {
              $start = 0;
              $end = $n-$amount;
        } elseif(     $dir == "left") {
              $start = $amount;
              $end = $n;
        }
       
        return     substr($str, $start, $end);
      } else return     false;
    }
    ?>

    Enjoy ;)
    up
    1
    vnonov at gmail dot com / Viktor Nonov
    14 years ago
    <?php

    //removes string from the end of other

    function removeFromEnd($string, $stringToRemove) {
            $stringToRemoveLen = strlen($stringToRemove);
            $stringLen = strlen($string);
       
            $pos = $stringLen - $stringToRemoveLen;

            $out = substr($string, 0, $pos);

        return     $out;
    }

    $string = 'picture.jpg.jpg';
    $string = removeFromEnd($string, '.jpg');
    ?>
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    -2
    robinhood70 at live dot ca
    3 years ago
    Prior to PHP 8, specifying length with zero-length strings or non-string values as input can produce potentially unexpected results.

    <?php
    foreach (['normal', '', true, false, NULL] as $value) {
        echo     gettype(substr($value, 0, 10)) . ' ' . substr($value, 0, 10);
    }

    /*
    string normal
    boolean
    string 1
    boolean
    boolean
    */
    ?>
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    1
    webmaster at oehoeboeroe dot nl
    15 years ago
    You might expect substr('123456', 6) to return an empty string. Instead it returns boolean FALSE.

    This behavior should be mentioned in the Return Values section of the manual. Instead it is only mentioned in the Parameters section.

    If you need an empty string instead of a boolean FALSE you should typecast the result to a string.

    <?php
    $a     = substr('123456', 6);              // equivalent to $a = FALSE
    $a = (string) substr('123456', 6);   // equivalent to $a = '';
    ?>
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    1
    steve at unicycle dot co dot nz
    19 years ago
    To quickly trim an optional trailing slash off the end of a path name:

    if (substr( $path, -1 ) == '/') $path = substr( $path, 0, -1 );
    up
    1
    Bradley from California
    18 years ago
    Add on to (a function originally written by) "Matias from Argentina": str_format_number function.

    Just added handling of $String shorter then $Format by adding a side to start the fill and a string length to the while loop.

    <?php
    function str_format_number($String, $Format, $Start = 'left'){
            //If we want to fill from right to left incase string is shorter then format
            if ($Start == 'right') {
                $String = strrev($String);
                $Format = strrev($Format);
        }
        if(    $Format == '') return $String;
        if(    $String == '') return $String;   
            $Result = '';
            $FormatPos = 0;
            $StringPos = 0;
        while ((    strlen($Format) - 1) >= $FormatPos && strlen($String) > $StringPos) {
                //If its a number => stores it
                if (is_numeric(substr($Format, $FormatPos, 1))) {
                    $Result .= substr($String, $StringPos, 1);
                    $StringPos++;
                    //If it is not a number => stores the caracter
                } else {
                    $Result .= substr($Format, $FormatPos, 1);
            }
                //Next caracter at the mask.
                $FormatPos++;
        }
        if (    $Start == 'right') $Result = strrev($Result);
        return     $Result;
    }
    ?>
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    1
    frank at jkelloggs dot dk
    19 years ago
    Regarding the utf8_substr function from lmak: The pattern '/./u' doesn't match newline characters. This means that the substring from 0 to the total length of the string will miss the number of characters in the end matching the number of newlines in the string. To fix this one can add the s modifier (PCRE_DOTALL) in the pattern:

    <?php
    function utf8_substr($str,$start)
    {
           preg_match_all("/./su", $str, $ar);

       if(    func_num_args() >= 3) {
               $end = func_get_arg(2);
           return     join("",array_slice($ar[0],$start,$end));
       } else {
           return     join("",array_slice($ar[0],$start));
       }
    }
    ?>
    up
    0
    link
    15 years ago
    And as always there is bound to be a bug:

    <?php
    function strlen_entities($text)
    {
            preg_match_all(
                '/((?:&(?:#[0-9]{2,}|[a-z]{2,});)|(?:[^&])|'.       
                '(?:&(?!\w;)))s',$text,$textarray);
        return     count($textarray[0]);
    }
    function     substr_entities($text,$start,$limit=0)
    {
            $return = '';
            preg_match_all(
                '/((?:&(?:#[0-9]{2,}|[a-z]{2,});)|(?:[^&])|'.       
                '(?:&(?!\w;)))s',$text,$textarray);
            $textarray = $textarray[0];
            $numchars = count($textarray)-1;
        if (    $start>=$numchars)
            return     false;
        if (    $start<0)
        {
                $start = ($numchars)+$start+1;
        }
        if (    $start>=0)
        {
            if (    $limit==0)
            {
                    $end=$numchars;
            }
            elseif (    $limit>0)
            {
                    $end = $start+($limit-1);
            }
            else
            {
                    $end = ($numchars)+$limit;
            }

            for (    $i=$start;($i<=$end && isset($textarray[$i]));$i++)
            {
                    $return .= $textarray[$i];
            }
            return     $return;
        }
    }
    ?>
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    0
    kriskra at gmail dot com
    16 years ago
    The javascript charAt equivalent in php of felipe has a little bug. It's necessary to compare the type (implicit) aswell or the function returns a wrong result:
    <?php
    function charAt($str,$pos) {
        return (    substr($str,$pos,1) !== false) ? substr($str,$pos,1) : -1;
    }
    ?>
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    0
    ivanhoe011 at gmail dot com
    19 years ago
    If you need just a single character from the string you don't need to use substr(), just use curly braces notation:

    <?php
            // both lines will output the 3rd character
            echo substr($my_string, 2, 1);
        echo     $my_string{2}; 
    ?>

    curly braces syntax is faster and more readable IMHO..
    up
    0
    rob NOSPAM at clancentric dot net
    19 years ago
    I have developed a function with a similar outcome to jay's

    Checks if the last character is or isnt a space. (does it the normal way if it is)
    It explodes the string into an array of seperate works, the effect is... it chops off anything after and including the last space.

    <?php
    function limit_string($string, $charlimit)
    {
        if(    substr($string,$charlimit-1,1) != ' ')
        {
                $string = substr($string,'0',$charlimit);
                $array = explode(' ',$string);
                array_pop($array);
                $new_string = implode(' ',$array);

            return     $new_string.'...';
        }
        else
        {   
            return     substr($string,'0',$charlimit-1).'...';
        }
    }
    ?>
    up
    0
    woutermb at gmail dot com
    19 years ago
    Well this is a script I wrote, what it does is chop up long words with malicious meaning into several parts. This way, a chat in a table will not get stretched anymore.

    <?php

    function text($string,$limit=20,$chop=10){

    $text = explode(" ",$string);
    while(list(    $key, $value) = each($text)){
            $length = strlen($value);
        if(    $length >=20){
            for(    $i=0;$i<=$length;$i+=10){
                    $new .= substr($value, $i, 10);
                    $new .= " ";
            }
                 $post .= $new;
        }
        elseif(    $length <=15){
                $post .= $value;
        }
            $post .= " ";
    }
    return(    $post);
    }

    // for example, this would return:
    $output = text("Well this text doesn't get cut up, yet thisssssssssssssssssssssssss one does.", 10, 5);

    echo(    $output); // "Well this text doesn't get cup up, yet thiss sssss sssss sssss sssss sss one does."
    ?>

    I hope it was useful.. :)
    up
    -3
    Nadeem
    10 years ago
    Truncate a float number. Similar to the Excel trunc function.

    <?php
    function truncate_number($val,$decimals=2){
       
                $number=array();
                $number=explode(".",$val);           
                $result=0;

            if (    count($number)>1){

                    $result = $number[0] . "." . substr($number[1],0,$decimals); 
               
            } else {
           
                    $result = $val;
               
            }               

            unset(    $number);

            return     $result;   
    }

    echo     truncate_number(99.123456,2); //result = 99.12
    echo truncate_number(99.123456,5); //result = 99.12345
    echo truncate_number(99.123456,1); //result = 99.1
    ?>
    up
    -4
    m.m.j.kronenburg
    8 years ago
    <?php

    /**
      * Returns and extracts the portion of string specified by the
      * start and length parameters from the original string.
      *
      * This function is simulair to function substr() except that it
      * removes the substring from the orignal string
      * (passed by reference).
      *
      * @param string $string      The input string.
      * @param integer $start      The start position (see substr() for
      *                            explanation).
      * @param integer $length     The length (see substr()
      *                            for explanation).
      * @return mixed              The substring or FALSE (see substr()
      *                            for explanation).
      **/
    function substrex(&$string, $start, $length = PHP_INT_MAX)
    {
      if(    $start > strlen($string)) { return false; }
      if(empty(    $length))           { return ''; }
      if(    $start < 0) { $start = max(0, $start + strlen($string)); }
          $end = ($length < 0) ?
            strlen($string) + $length :
            min(strlen($string), $start + $length);
      if(    $end < $start) { return false; }
          $length = $end - $start;
          $substr = substr($string, $start, $length);
          $string = substr($string, 0, $start).substr($string, $end); 
      return     $substr;
    }

    ?>
    up
    -9
    man13or at hotmail dot fr
    5 years ago
    Shortcuts :

    Getting the first character of a string
    substr($string, 1)

    Getting the last character of a string
    substr($string, -1)

    Remove the first character of a string
    substr($string,1)

    Remove the last character of a string
    substr($string, 0, -1)
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