PHP 5.4.33 Released

Funciones de strings

Ver también

Para un mejor manejo de cadenas y manipulacion de funciones revisar a las funciones de expresiones regulares del POSIX y las Funciones de expresiones regualres compotaibles con Perl .

Tabla de contenidos

  • addcslashes — Escapa una cadena al estilo de C
  • addslashes — Escapa un string con barras invertidas
  • bin2hex — Convierte datos binarios en su representación hexadecimal
  • chop — Alias de rtrim
  • chr — Devuelve un caracter específico
  • chunk_split — Divide una cadena en trozos más pequeños
  • convert_cyr_string — Convierte de un juego de caracteres cirílico a otro juego de caracteres cirílico
  • convert_uudecode — Descodifica una cadena codificada mediante uuencode
  • convert_uuencode — Codifica, mediante uuencode, una cadena
  • count_chars — Devuelve información sobre los caracteres usados en una cadena
  • crc32 — Calcula el polinomio crc32 de una cadena
  • crypt — Hashing de una sola vía de un string
  • echo — Muestra una o más cadenas
  • explode — Divide un string en varios string
  • fprintf — Escribir una cadena con formato a una secuencia
  • get_html_translation_table — Devuelve la tabla de traducción utilizada por htmlspecialchars y htmlentities
  • hebrev — Convierte texto hebreo lógico a texto visual
  • hebrevc — Convertir texto de hebreo lógico a texto visual con conversión de línea nueva
  • hex2bin — Decodifica una cadena binaria codificada hexadecimalmente
  • html_entity_decode — Convierte todas las entidades HTML a sus caracteres correspondientes
  • htmlentities — Convierte todos los caracteres aplicables a entidades HTML
  • htmlspecialchars_decode — Convierte entidades HTML especiales de nuevo en caracteres
  • htmlspecialchars — Convierte caracteres especiales en entidades HTML
  • implode — Une elementos de un array en un string
  • join — Alias de implode
  • lcfirst — Pasa a minúscula el primer caracter de un string
  • levenshtein — Cálculo de la distancia Levenshtein entre dos strings
  • localeconv — Obtener información sobre el formato numérico
  • ltrim — Retira espacios en blanco (u otros caracteres) del inicio de un string
  • md5_file — Calcula el resumen criptográfico md5 de un archivo dado
  • md5 — Calcula el hash md5 de un string
  • metaphone — Calcula la clave metaphone de un string
  • money_format — Da formato a un número como un string de moneda
  • nl_langinfo — Consulta información sobre el idioma y la configuración regional
  • nl2br — Inserta saltos de línea HTML antes de todas las nuevas líneas de un string
  • number_format — Formatear un número con los millares agrupados
  • ord — devuelve el valor ASCII de una caracter
  • parse_str — Convierte el string en variables
  • print — Mostrar una cadena
  • printf — Imprimir una cadena con formato
  • quoted_printable_decode — Convierte un string quoted-printable en un string de 8 bits
  • quoted_printable_encode — Convierte un string de 8 bits en un string quoted-printable
  • quotemeta — Escapa meta caracteres
  • rtrim — Retira los espacios en blanco (u otros caracteres) del final de un string
  • setlocale — Establecer la información de la configuración regional
  • sha1_file — Calcula el hash sha1 de un archivo
  • sha1 — Calcula el hash sha1 de un string
  • similar_text — Calcula la similitud entre dos strings
  • soundex — Calcula la clave soundex de un string
  • sprintf — Devuelve un string formateado
  • sscanf — Interpreta un string de entrada de acuerdo con un formato
  • str_getcsv — Convierte un string con formato CSV a un array
  • str_ireplace — Versión insensible a mayúsculas y minúsculas de str_replace
  • str_pad — Rellena un string hasta una longitud determinada con otro string
  • str_repeat — Repite un string
  • str_replace — Reemplaza todas las apariciones del string buscado con el string de reemplazo
  • str_rot13 — Realizar la transformación rot13 sobre una cadena
  • str_shuffle — Reordena aleatoriamente una cadena
  • str_split — Convierte un string en un array
  • str_word_count — Devuelve información sobre las palabras utilizadas en un string
  • strcasecmp — Comparación de string segura a nivel binario e insensible a mayúsculas y minúsculas
  • strchr — Alias de strstr
  • strcmp — Comparación de string segura a nivel binario
  • strcoll — Comparación de cadenas basada en la localidad
  • strcspn — Encuentra la longitud del segmento inicial que no coincida con la máscara
  • strip_tags — Retira las etiquetas HTML y PHP de un string
  • stripcslashes — Desmarca la cadena marcada con addcslashes
  • stripos — Encuentra la posición de la primera aparición de un substring en un string sin considerar mayúsculas ni minúsculas
  • stripslashes — Quita las barras de un string con comillas escapadas
  • stristr — strstr insensible a mayúsculas y minúsculas
  • strlen — Obtiene la longitud de un string
  • strnatcasecmp — Comparación de strings, insensible a mayúsculas y minúsculas, utilizando un algoritmo de "orden natural"
  • strnatcmp — Comparación de strings utilizando un algoritmo de "orden natural"
  • strncasecmp — Comparación de los primeros n caracteres de cadenas, segura con material binario e insensible a mayúsculas y minúsculas
  • strncmp — Comparación segura a nivel binario de los primeros n caracteres entre strings
  • strpbrk — Buscar una cadena por cualquiera de los elementos de un conjunto de caracteres
  • strpos — Encuentra la posición de la primera ocurrencia de un substring en un string
  • strrchr — Encuentra la última aparición de un caracter en un string
  • strrev — Invierte una string
  • strripos — Encuentra la posición de la última aparición de un substring insensible a mayúsculas y minúsculas en un string
  • strrpos — Encuentra la posición de la última aparición de un substring en un string
  • strspn — Encuentra la longitud del segmento inicial de un string que consista únicamente en caracteres contenidos dentro de una máscara dada.
  • strstr — Encuentra la primera aparición de un string
  • strtok — Tokeniza string
  • strtolower — Convierte una cadena a minúsculas
  • strtoupper — Convierte un string a mayúsculas
  • strtr — Convierte caracteres o reemplaza substrings
  • substr_compare — Comparación segura a nivel binario de dos o más strings desde un índice hasta una longitud de caracteres dada
  • substr_count — Cuenta el número de apariciones del substring
  • substr_replace — Reemplaza el texto dentro de una porción de un string
  • substr — Devuelve parte de una cadena
  • trim — Elimina espacio en blanco (u otro tipo de caracteres) del inicio y el final de la cadena
  • ucfirst — Convierte el primer caracter de una cadena a mayúsculas
  • ucwords — Convierte a mayúsculas el primer caracter de cada palabra en una cadena
  • vfprintf — Escribe un string con formato en un flujo
  • vprintf — Muestra una cadena con formato
  • vsprintf — Devuelve una cadena con formato
  • wordwrap — Ajusta un string hasta un número dado de caracteres
add a note add a note

User Contributed Notes 24 notes

up
2
kristin at greenapple dot on dot ca
9 years ago
I really searched for a function that would do this as I've seen it in other languages but I couldn't find it here. This is particularily useful when combined with substr() to take the first part of a string up to a certain point.

strnpos() - Find the nth position of needle in haystack.

<?php

   
function strnpos($haystack, $needle, $occurance, $pos = 0) {
       
        for (
$i = 1; $i <= $occurance; $i++) {
           
$pos = strpos($haystack, $needle, $pos) + 1;
        }
        return
$pos - 1;
       
    }

?>

Example: Give me everything up to the fourth occurance of '/'.

<?php

    $haystack
= "/home/username/www/index.php";
   
$needle = "/";
   
   
$root_dir = substr($haystack, 0, strnpos($haystack, $needle, 4));
   
    echo
$root_dir;
   
?>

Returns: /home/username/www

Use this example with the server variable $_SERVER['SCRIPT_NAME'] as the haystack and you can self-discover a document's root directory for the purposes of locating global files automatically!
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1
webmaster at cafe-clope dot net
9 years ago
A comprehensive concatenation function, that works with array and strings

<?php
function str_cat() {
 
$args = func_get_args() ;
   
 
// Asserts that every array given as argument is $dim-size.
  // Keys in arrays are stripped off.
  // If no array is found, $dim stays unset.
 
foreach($args as $key => $arg) {
    if(
is_array($arg)) {
      if(!isset(
$dim))
       
$dim = count($arg) ;
      elseif(
$dim != count($arg))
        return
FALSE ;
     
$args[$key] = array_values($arg) ;
    }
  }
       
 
// Concatenation
 
if(isset($dim)) {
   
$result = array() ;
    for(
$i=0;$i<$dim;$i++) {
     
$result[$i] = '' ;
      foreach(
$args as $arg)
       
$result[$i] .= ( is_array($arg) ? $arg[$i] : $arg ) ;
    }
    return
$result ;
  } else {
    return
implode($args) ;
  }
}
?>

A simple example :

<?php
str_cat
(array(1,2,3), '-', array('foo' => 'foo', 'bar' => 'bar', 'noop' => 'noop')) ;
?>

will return :
Array (
  [0] => 1-foo
  [1] => 2-bar
  [2] => 3-noop
)

More usefull :

<?php
$myget
= $_GET ; // retrieving previous $_GET values
$myget['foo'] = 'b a r' ; // changing one value
$myget = str_cat(array_keys($myget), '=', array_map('rawurlencode', array_values($myget))) ;
$querystring = implode(ini_get('arg_separator.output'), $myget)) ;
?>

will return a valid querystring with some values changed.

Note that <?php str_cat('foo', '&', 'bar') ; ?> will return 'foo&bar', while <?php str_cat(array('foo'), '&', 'bar') ; ?> will return array(0 => foo&bar)
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1
admin at fivestarbuy dot com
8 years ago
This example lets you parse an unparsed strings variables. Warning: This could cause security leaks if you allow users to pass $variables through this engine. I recommend only using this for your Content Management System.

<?
$mytime
=time();
$mydog="My Dog Ate My PHP!";

# Your Parsing String:
$s1 = 'Hyphen Variable Preserving: $mytime, and $mydog';
echo
"Before: <br><br>$s1<br><br>";

# Remember, wherever you define this, it will not be defined GLOBAL into the function
# which is why we define it here. Defining it global could lead to security issues.
$vardata=get_defined_vars();

# Parse the string
$s1 = StrParse($s1,$vardata);

echo
"After: <br><br>$s1";

function
StrParse($str,$vardata) {
# Takes a string, or piece of data, that contains PHP Variables

# For example, unparsed variables like:  Test using time: $mytime
# This example shows $mytime, and not the actual variable value.
# The end result shows the actual variable value of $mytime.

# This is useful for building a content management system,
# and directing your variables into your content data,
# where content is stored in a file or database, unparsed.
# Of course this could slow down page loads, but it's a good way
# to parse data from current variables into your loaded new data
# making it compatible.

# Then the variables are replaced with the actual variable..
$getvarkeys=array_keys($vardata);
$ret=$str;
for (
$x=0; $x < count($getvarkeys); $x++) {
   
$myvar=$getvarkeys[$x];
   
#echo "Variable: " . $myvar . " [" . $vardata[$myvar] . "]<br>";
   
$ret=str_replace('$' . $myvar, $vardata[$myvar], $ret);
}
return
$ret;

}

?>
up
0
str at maphpia dot com
1 year ago
I was looking for a function to find the common substring in 2 different strings. I tried both the mb_string_intersect and string_intersect functions listed here but didn't work for me. I found the algorithm at http://en.wikibooks.org/wiki/Algorithm_implementation/Strings/Longest_common_substring#PHP so here I post you the function

<?php

/**
* Finds the matching string between 2 strings
*
* @param string $string1
* @param string $string2
* @param number $minChars
*
* @return NULL|string
*
* @link http://en.wikibooks.org/wiki/Algorithm_implementation/Strings/Longest_common_substring#PHP
*/
function string_intersect($string_1, $string_2)
{
   
$string_1_length = strlen($string_1);
   
$string_2_length = strlen($string_2);
   
$return          = "";

    if (
$string_1_length === 0 || $string_2_length === 0) {
       
// No similarities
       
return $return;
    }

   
$longest_common_subsequence = array();

   
// Initialize the CSL array to assume there are no similarities
   
for ($i = 0; $i < $string_1_length; $i++) {
       
$longest_common_subsequence[$i] = array();
        for (
$j = 0; $j < $string_2_length; $j++) {
           
$longest_common_subsequence[$i][$j] = 0;
        }
    }

   
$largest_size = 0;

    for (
$i = 0; $i < $string_1_length; $i++) {
        for (
$j = 0; $j < $string_2_length; $j++) {
           
// Check every combination of characters
           
if ($string_1[$i] === $string_2[$j]) {
               
// These are the same in both strings
               
if ($i === 0 || $j === 0) {
                   
// It's the first character, so it's clearly only 1 character long
                   
$longest_common_subsequence[$i][$j] = 1;
                } else {
                   
// It's one character longer than the string from the previous character
                   
$longest_common_subsequence[$i][$j] = $longest_common_subsequence[$i - 1][$j - 1] + 1;
                }

                if (
$longest_common_subsequence[$i][$j] > $largest_size) {
                   
// Remember this as the largest
                   
$largest_size = $longest_common_subsequence[$i][$j];
                   
// Wipe any previous results
                   
$return       = "";
                   
// And then fall through to remember this new value
               
}

                if (
$longest_common_subsequence[$i][$j] === $largest_size) {
                   
// Remember the largest string(s)
                   
$return = substr($string_1, $i - $largest_size + 1, $largest_size);
                }
            }
           
// Else, $CSL should be set to 0, which it was already initialized to
       
}
    }

   
// Return the list of matches
   
return $return;
}
up
0
t0russ at gmail dot com
9 years ago
to kristin at greenaple dot on dot ca:
thanx for sharing.
your function in recursive form proved to be slightly faster and it returns false (as it should) when the character is not found instead of number 0:
<?php
function strnposr($haystack, $needle, $occurance, $pos = 0) {
    return (
$occurance<2)?strpos($haystack, $needle, $pos):strnposr($haystack,$needle,$occurance-1,strpos($haystack, $needle, $pos) + 1);
}
?>
up
0
james dot d dot baker at gmail dot com
9 years ago
<?php
/*
Written By James Baker, May 27th 2005

sentenceCase($string);
    $string: The string to convert to sentence case.

Converts a string into proper sentence case (First letter of each sentance capital, all the others smaller)

Example Usage:
echo sentenceCase("HELLO WORLD!!! THIS IS A CAPITALISED SENTENCE. this isn't.");

Returns:
Hello world!!! This is a capitalised sentence. This isn't.
*/

function sentenceCase($s){
   
$str = strtolower($s);
   
$cap = true;
   
    for(
$x = 0; $x < strlen($str); $x++){
       
$letter = substr($str, $x, 1);
        if(
$letter == "." || $letter == "!" || $letter == "?"){
           
$cap = true;
        }elseif(
$letter != " " && $cap == true){
           
$letter = strtoupper($letter);
           
$cap = false;
        }
       
       
$ret .= $letter;
    }
   
    return
$ret;
}
?>
up
0
Anonymous
9 years ago
In response to hackajar <matt> yahoo <trot> com,

No string-to-array function exists because it is not needed. If you reference a string with an offset like you do with an array, the character at that offset will be return. This is documented in section III.11's "Strings" article under the "String access and modification by character" heading.
up
0
andy a t onesandzeros d o t biz
9 years ago
I use these little doo-dads quite a bit. I just thought I'd share them and maybe save someone a little time. No biggy. :)

// returns true if $str begins with $sub
function beginsWith( $str, $sub ) {
    return ( substr( $str, 0, strlen( $sub ) ) == $sub );
}

// return tru if $str ends with $sub
function endsWith( $str, $sub ) {
    return ( substr( $str, strlen( $str ) - strlen( $sub ) ) == $sub );
}

// trims off x chars from the front of a string
// or the matching string in $off is trimmed off
function trimOffFront( $off, $str ) {
    if( is_numeric( $off ) )
        return substr( $str, $off );
    else
        return substr( $str, strlen( $off ) );
}

// trims off x chars from the end of a string
// or the matching string in $off is trimmed off
function trimOffEnd( $off, $str ) {
    if( is_numeric( $off ) )
        return substr( $str, 0, strlen( $str ) - $off );
    else
        return substr( $str, 0, strlen( $str ) - strlen( $off ) );
}
up
0
[tab!]
9 years ago
//
// string strtrmvistl(  string str, [int maxlen = 64],
//                      [bool right_justify = false],
//                      [string delimter = "<br>\n"])
//
// splits a long string into two chunks (a start and an end chunk)
// of a given maximum length and seperates them by a given delimeter.
// a second chunk can be right-justified within maxlen.
// may be used to 'spread' a string over two lines.
//

function strtrmvistl($str, $maxlen = 64, $right_justify = false, $delimter = "<br>\n") {
    if(($len = strlen($str = chop($str))) > ($maxlen = max($maxlen, 12))) {
        $newstr = substr($str, 0, $maxlen - 3);

        if($len > ($maxlen - 3)) {
            $endlen = min(($len - strlen($newstr)), $maxlen - 3);
            $newstr .= "..." . $delimter;

            if($right_justify)
                $newstr .= str_pad('', $maxlen - $endlen - 3, ' ');

            $newstr .= "..." . substr($str, $len - $endlen);
        }

        return($newstr);
    }

    return($str);
}
up
0
terry dot greenlaw at logicalshift dot com
10 years ago
Here's a simpler "simplest" way to toggle through a set of 1..n colors for web backgrounds:

<?php
$colours
= array('#000000', '#808080', '#A0A0A0', '#FFFFFF');

// Get a colour
$color = next($colors) or $color = reset($colors);
?>

The code doesn't need to know anything about the number of elements being cycled through. That way you won't have to tracking down all the code when changing the number of colors or the color values.
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-1
navarr at gmail dot com
8 years ago
stripos for PHP4.x

<?php
 
function stripos($haystack,$needle) {
    return
strpos(strtoupper($haystack),strtoupper($needle));
  }
?>
up
-1
administrador(ensaimada)sphoera(punt)com
8 years ago
I've prepared this simple function to obtain a string delimited between tags (not only XML tags!). Anybody needs something like this?.

<?php

function get_string_between($string, $start, $end){
   
$string = " ".$string;
    
$ini = strpos($string,$start);
     if (
$ini == 0) return "";
    
$ini += strlen($start);    
    
$len = strpos($string,$end,$ini) - $ini;
     return
substr($string,$ini,$len);
}

$string = "this [custom] function is useless!!";
echo
get_string_between($string,"[","]");
// must return "custom";
?>
more functions at http://www.sphoera.com
up
-1
Anonymous
8 years ago
to: james dot d dot baker at gmail dot com

PHP has a builtin function  for doing what your function does,

http://php.net/ucfirst
http://php.net/ucwords
up
-1
mike &#34;eyes&#34; moe
7 years ago
Here is a truly random string generator it uses the most common string functions it will work on anywhere.

<?php
   
function random_string($max = 20){
       
$chars = explode(" ", "a b c d e f g h i j k l m n o p q r s t u v w x y z 0 1 2 3 4 5 6 7 8 9");
        for(
$i = 0; $i < $max; $i++){
           
$rnd = array_rand($chars);
           
$rtn .= base64_encode(md5($chars[$rnd]));
        }
        return
substr(str_shuffle(strtolower($rtn)), 0, $max);
    }
?>
up
-2
da (dot) blayde (a t) gmail (dot) com
8 years ago
Sometimes when converting integers to strings, it looks better to have the number spelled out. I wrote this function that converts integers from -999 to 999 into spelled out strings:

function int2str($int=0){
$doOnes=true;
$neg=$int<0?true:false;
$int=abs(round($int));
$str='';
switch(strlen($int)){
  case 1:$int='0'.$int;
  case 2:$int='0'.$int;
  case 3:$int.='';break;
  default:return $int;
}
switch($int{0}){
  case 1:$str.='one-hundred-';break;
  case 2:$str.='two-hundred-';break;
  case 3:$str.='three-hundred-';break;
  case 4:$str.='four-hundred-';break;
  case 5:$str.='five-hundred-';break;
  case 6:$str.='six-hundred-';break;
  case 7:$str.='seven-hundred-';break;
  case 8:$str.='eight-hundred-';break;
  case 9:$str.='nine-hundred-';break;
}
switch($int{1}){
  case 1:
   switch($int{2}){
    case 0:$str.='ten-';break;
    case 1:$str.='eleven-';break;
    case 2:$str.='twelve-';break;
    case 3:$str.='thirteen-';break;
    case 4:$str.='fourteen-';break;
    case 5:$str.='fifteen-';break;
    case 6:$str.='sixteen-';break;
    case 7:$str.='seventeen-';break;
    case 8:$str.='eighteen-';break;
    case 9:$str.='nineteen-';break;
   }
   $doOnes=false;
  break;
  case 2:$str.='twenty-';break;
  case 3:$str.='thirty-';break;
  case 4:$str.='forty-';break;
  case 5:$str.='fifty-';break;
  case 6:$str.='sixty-';break;
  case 7:$str.='seventy-';break;
  case 8:$str.='eighty-';break;
  case 9:$str.='ninety-';break;
}
if($doOnes){
  switch($int{2}){
   case 1:$str.='one-';break;
   case 2:$str.='two-';break;
   case 3:$str.='three-';break;
   case 4:$str.='four-';break;
   case 5:$str.='five-';break;
   case 6:$str.='six-';break;
   case 7:$str.='seven-';break;
   case 8:$str.='eight-';break;
   case 9:$str.='nine-';break;
}}
$str=substr($str,0,-1);
if($neg){
  $str='negative '.$str;
}
if($int=='000'){
  $str='zero';
}
return $str;
}

Hope this helps someone,
-Blayde
up
-1
rh at richardhoward dot net
9 years ago
<?php
/**
Utility class: static methods for cleaning & escaping untrusted (i.e.
user-supplied) strings.

Any string can (usually) be thought of as being in one of these 'modes':

pure = what the user actually typed / what you want to see on the page /
       what is actually stored in the DB
gpc  = incoming GET, POST or COOKIE data
sql  = escaped for passing safely to RDBMS via SQL (also, data from DB
       queries and file reads if you have magic_quotes_runtime on--which
       is rare)
html = safe for html display (htmlentities applied)

Always knowing what mode your string is in--using these methods to
convert between modes--will prevent SQL injection and cross-site scripting.

This class refers to its own namespace (so it can work in PHP 4--there is no
self keyword until PHP 5). Do not change the name of the class w/o changing
all the internal references.

Example usage: a POST value that you want to query with:
$username = Str::gpc2sql($_POST['username']);
*/

//This sets SQL escaping to use slashes; for Sybase(/MSSQL)-style escaping
// ( ' --> '' ), set to true.
define('STR_SYBASE', false);

class
Str {
    function
gpc2sql($gpc, $maxLength = false)
    {
        return
Str::pure2sql(Str::gpc2pure($gpc), $maxLength);
    }
    function
gpc2html($gpc, $maxLength = false)
    {
        return
Str::pure2html(Str::gpc2pure($gpc), $maxLength);
    }
    function
gpc2pure($gpc)
    {
        if (
ini_get('magic_quotes_sybase'))
           
$pure = str_replace("''", "'", $gpc);
        else
$pure = get_magic_quotes_gpc() ? stripslashes($gpc) : $gpc;
        return
$pure;
    }
    function
html2pure($html)
    {
        return
html_entity_decode($html);
    }
    function
html2sql($html, $maxLength = false)
    {
        return
Str::pure2sql(Str::html2pure($html), $maxLength);
    }
    function
pure2html($pure, $maxLength = false)
    {
        return
$maxLength ? htmlentities(substr($pure, 0, $maxLength))
                          :
htmlentities($pure);
    }
    function
pure2sql($pure, $maxLength = false)
    {
        if (
$maxLength) $pure = substr($pure, 0, $maxLength);
        return (
STR_SYBASE)
               ?
str_replace("'", "''", $pure)
               :
addslashes($pure);
    }
    function
sql2html($sql, $maxLength = false)
    {
       
$pure = Str::sql2pure($sql);
        if (
$maxLength) $pure = substr($pure, 0, $maxLength);
        return
Str::pure2html($pure);
    }
    function
sql2pure($sql)
    {
        return (
STR_SYBASE)
               ?
str_replace("''", "'", $sql)
               :
stripslashes($sql);
    }
}
?>
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-1
Stephen Dewey
5 years ago
If you want a function to return all text in a string up to the Nth occurrence of a substring, try the below function.

Works in PHP >= 5.

(Pommef provided another sample function for this purpose below, but I believe it is incorrect.)

<?php

// Returns all of $haystack up to (but excluding) the $n_occurrence occurrence of $needle. Therefore:
//        If there are < $n_occurrence occurrences of $needle in $haystack, the entire string will be returned.
//        If there are >= $n_occurrence occurrences of $needle in $haystack, the returned string will end before the $n_occurrence'th needle.
// This function only makes sense for $n_occurrence >= 1
function nsubstr($needle, $haystack, $n_occurrence)
{
   
// After exploding by $needle, every entry in $arr except (possibly) part of the last entry should have its content returned.
   
$arr = explode($needle,$haystack,$n_occurrence);
   
// Examine last entry in $arr. If it contains $needle, cut out all text except for the text before $needle.
   
$last = count($arr) - 1;
   
$pos_in_last = strpos($arr[$last],$needle);
   
    if (
$pos_in_last !== false)
       
$arr[$last] = substr($arr[$last],0,$pos_in_last);
   
    return
implode($needle,$arr);
}

$string = 'd24jkdslgjldk2424jgklsjg24jskgldjk24';

print
'S:  ' . $string . '<br>';
print
'1: ' . nsubstr('24',$string,1) . '<br>';
print
'2: ' . nsubstr('24',$string,2) . '<br>';
print
'3: ' . nsubstr('24',$string,3) . '<br>';
print
'4: ' . nsubstr('24',$string,4) . '<br>';
print
'5: ' . nsubstr('24',$string,5) . '<br>';
print
'6: ' . nsubstr('24',$string,6) . '<br>';
print
'7: ' . nsubstr('24',$string,7) . '<br>';

/*
// prints:
S: d24jkdslgjldk2424jgklsjg24jskgldjk24
1: d
2: d24jkdslgjldk
3: d24jkdslgjldk24
4: d24jkdslgjldk2424jgklsjg
5: d24jkdslgjldk2424jgklsjg24jskgldjk
6: d24jkdslgjldk2424jgklsjg24jskgldjk24
7: d24jkdslgjldk2424jgklsjg24jskgldjk24
*/

?>

Note that this function can be combined with wordwrap() to accomplish a routine but fairly difficult web design goal, namely, limiting inline HTML text to a certain number of lines. wordwrap() can break your string using <br>, and then you can use this function to only return text up to the N'th <br>.

You will still have to make a conservative guess of the max number of characters per line with wordwrap(), but you can be more precise than if you were simply truncating a multiple-line string with substr().

See example:

<?php

$text
= 'Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Pellentesque id massa. Duis sollicitudin ipsum vel diam. Aliquam pulvinar sagittis felis. Nullam hendrerit semper elit. Donec convallis mollis risus. Cras blandit mollis turpis. Vivamus facilisis, sapien at tincidunt accumsan, arcu dolor suscipit sem, tristique convallis ante ante id diam. Curabitur mollis, lacus vel gravida accumsan, enim quam condimentum est, vitae rutrum neque magna ac enim.';

$wrapped_text = wordwrap($text,100,'<br>',true);

$three_lines = nsubstr('<br>',$wrapped_text,3);

print
'<br><br>' . $three_lines;

$four_lines = nsubstr('<br>',$wrapped_text,4);

print
'<br><br>' . $four_lines;

/*
prints:

Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Pellentesque id massa. Duis sollicitudin
ipsum vel diam. Aliquam pulvinar sagittis felis. Nullam hendrerit semper elit. Donec convallis
mollis risus. Cras blandit mollis turpis. Vivamus facilisis, sapien at tincidunt accumsan, arcu

Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Pellentesque id massa. Duis sollicitudin
ipsum vel diam. Aliquam pulvinar sagittis felis. Nullam hendrerit semper elit. Donec convallis
mollis risus. Cras blandit mollis turpis. Vivamus facilisis, sapien at tincidunt accumsan, arcu
dolor suscipit sem, tristique convallis ante ante id diam. Curabitur mollis, lacus vel gravida

*/

?>
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-1
Verdauga
6 years ago
Just a note in regards to bloopletech a few posts down:

The word "and" should not be used when converting numbers to text.  "And" (at least in US English) should only be used to indicate the decimal place.

Example:
1,796,706 => one million, seven hundred ninety-six thousand, seven hundred six.
594,359.34 => five hundred ninety four thousand, three hundred fifty nine and thirty four hundredths
up
-1
php at moechofe dot com
9 years ago
<?php
 
/*
  * str_match
  *
  * return a string with only cacacteres defined in a expression return false if the expression is not valid
  *
  * @param $str string the string
  * @param $match the expression based on the class definition off a PCRE regular expression.
  *   the '[', ']', '\' and '^' at class start need to be escaped.
  *   like : -a-z0-9_@.
  */
 
function str_match( $str, $match )
  {
   
$return = '';
    if(
eregi( '(.*)', $match, $class ) )
    {
     
$match = '['.$regs[1].']';
      for(
$i=0; $i<strlen($str); $i++ )
      if(
ereg( '['.$class[1].']', $str[$i] ) )
     
$return .= $str{$i};
      return
$return;
    }
    else return
false;
  }

 
/*
  * example
  * accept only alphanum caracteres from the GET/POST parameters 'a'
  */

 
if( ! empty($_REQUEST['a']) )
   
$_REQUEST['a'] = str_match( $_REQUEST['a'], 'a-zA-Z0-9' );
  else
   
$_REQUEST['a'] = 'default';
?>
up
-1
m
7 years ago
Regarding the code for the function beginsWith($str, $sub), I found that it has problems when only one character is present after the string searched for. I found that this works better instead:

<?php
function beginsWith($str, $sub) {
    return (
strncmp($str, $sub, strlen($sub)) == 0);
}
?>
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-1
Pommef
9 years ago
Example: Give me everything up to the fourth occurance of '/'.

<?php

   $haystack
= "/home/username/www/index.php";
  
$needle = "/";
 
   function
strnpos($haystack, $needle, $occurance, $pos = 0) {
       
       
$res = implode($needle,$haystack);
       
       
$res = array_slice($res, $pos$occurance);
       
        return
explode ($needle,$res);
    }
?>
up
-2
SteveRusin
8 years ago
The functions below:

function beginsWith( $str, $sub )
function endsWith( $str, $sub )

Are correct, but flawed.  You'd need to use the === operator instead:

function beginsWith( $str, $sub ) {
   return ( substr( $str, 0, strlen( $sub ) ) === $sub );
}
function endsWith( $str, $sub ) {
   return ( substr( $str, strlen( $str ) - strlen( $sub ) ) === $sub );
}

Otherwise, endsWith would return "foobar.0" ends with ".0" as well as "0" or "00" or any amount of zeros because numerically .0 does equal 0.
up
-2
admin at rotarymulundeast dot org
8 years ago
Here's an easier way to find nth...

function nth($numbex){
  if ($numbex%10 == 1 && $numbex%100 != 11) $sth='st';
  elseif ($numbex%10 == 2 && $numbex%100 != 12) $sth='nd';
  elseif ($numbex%10 == 3 && $numbex%100 != 13) $sth='rd';
  else $sth = 'th';
  return $sth;
}

there is is no need to check if the user has entered a non-integer as we may be using this function for expressing variables as well eg. ith value of x , nth root of z ,etc...
up
-4
Tomek Rychtyk
2 years ago
Get the intersection of two strings using array_intersect

<?php

function string_intersect($string1, $string2)
{
   
$array1 = $array2 = array();

    for(
$i = 0, $j = 0, $s1_len = strlen($string1), $s2_len = strlen($string2);($i < $s1_len) || ($j < $s2_len); $i++, $j++) {
        if(
$i < $s1_len) {
           
$array1[] = $string1[$i];
        }
        if(
$j < $s2_len) {
           
$array2[] = $string2[$j];
        }
    }

    return
implode('', array_intersect($array1, $array2));
}

?>

For more advanced comparison you can use array_uintersect as well.
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