SunshinePHP Developer Conference 2015

split

(PHP 4, PHP 5)

splitSuddivide una stringa in una matrice utilizzando le espressioni regolari

Descrizione

array split ( string $espressione_regolare , string $stringa [, int $limite ] )
Suggerimento

Poiché utilizza espressioni regolari con sintassi compatibile con Perl, preg_split(), è spesso una alternativa più veloce a split(). Se non si ha necessità delle capacità delle espressioni regolari, è più veloce l'utilizzo di explode(), che non richiede l'overhead del motore delle espressioni regolari.

La funzione restituisce una matrice di stringhe che sono delle sottostringhe del parametro stringa. Queste sono ottenute suddividendo il parametro secondo i limiti indicati dal parametro sensibile alle maiuscole espressione_regolare. Se viene specificato il parametro limite, la funzione restituisce una matrice con un numero di elementi al massimo pari a limite. L'ultimo elemento della matrice contiene la parte restante del parametro stringa fornito. Se si verificano errori la funzione split() restituisce FALSE.

Esempio di come estrapolare i primi 4 campi da una linea del file /etc/passwd:

Example #1 Esempio di split()

<?php
list($user$pass$uid$gid$extra) = split(":"$passwd_line5); 
?>

Se nella stringa passata vi sono n occorrenze del parametro espressione_regolare, la matrice restituita conterrà n+1 elementi. Invece, nel caso in cui non vi siano occorrenze della espressione_regolare, la matrice restituita conterrà un solo elemento. Ovviamente questo è valido anche nel caso in cui il parametro stringa è vuoto.

Nell'esempio che segue, si vedrà come analizzare una data il cui testo può contenere barre, punti o trattini:

Example #2 split() esempio

// Delimitatori di testo: barre, punti, trattini
$data = "04/30/1973"; 
list ($mese, $giorno, $anno) = split ('[/.-]', $data);
echo "Mese: $mese; Giorno: $giorno; Anno: $anno<br>\n";
?>

Gli utenti che cercano un modo di emulare il comportamento di Perl @chars = split('', $str), sono rimandati agli esempi di preg_split().

Occorre fare attenzione al fatto che il parametro espressione_regolare è una espressione regolare e, pertanto, se si devono riconoscere caratteri che sono considerati speciali per le espressioni regolari, occorre codificarli con i caratteri di escape. Se si ritiene che la funzione split () ( o anche le altre funzioni derivate da regex ) si comportino in modo anomalo, è opportuno leggere il file regex.7, incluso nella cartella regex/ della distribuzione di PHP. Questo file è nel formato del manuale di unix (man), pertanto per visualizzarlo occorre eseguire il comando man /usr/local/src/regex/regex.7.

Vedere anche: preg_split(), spliti(), explode(), implode(), chunk_split() e wordwrap().

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User Contributed Notes 25 notes

up
3
Dave Walter
6 years ago
In response to  the getCSVValues() function posted by justin at cam dot org, my testing indicates that it has a problem with a CSV string like this:

1,2,"3,""4,5"",6",7

This parses as:

array(6) {
  [0]=>
  string(1) "1"
  [1]=>
  string(1) "2"
  [2]=>
  string(4) "3,"4"
  [3]=>
  string(1) "5"
  [4]=>
  string(0) ""
  [5]=>
  string(1) "7"
}

instead of:

array(4) {
  [0]=>
  string(1) "1"
  [1]=>
  string(1) "2"
  [2]=>
  string(9) "3,"4,5",6"
  [3]=>
  string(1) "7"
}

To fix this, I changed the second substr_count to look for an odd number of quotes, as opposed to any quotes at all:

<?php
function getCSVValues($string, $separator=",")
{
   
$elements = explode($separator, $string);
    for (
$i = 0; $i < count($elements); $i++) {
       
$nquotes = substr_count($elements[$i], '"');
        if (
$nquotes %2 == 1) {
            for (
$j = $i+1; $j < count($elements); $j++) {
                if (
substr_count($elements[$j], '"') %2 == 1) { // Look for an odd-number of quotes
                    // Put the quoted string's pieces back together again
                   
array_splice($elements, $i, $j-$i+1,
                       
implode($separator, array_slice($elements, $i, $j-$i+1)));
                    break;
                }
            }
        }
        if (
$nquotes > 0) {
           
// Remove first and last quotes, then merge pairs of quotes
           
$qstr =& $elements[$i];
           
$qstr = substr_replace($qstr, '', strpos($qstr, '"'), 1);
           
$qstr = substr_replace($qstr, '', strrpos($qstr, '"'), 1);
           
$qstr = str_replace('""', '"', $qstr);
        }
    }
    return
$elements;
}
?>
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1
Jort
7 years ago
If you are looking for EITHER open square brackets OR close square brackets, then '[[]]' won't work (reasonably expected), but neither will '[\[\]]', nor with any number of escapes. HOWEVER, if your pattern is '[][]' it will work.
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1
robin at teddyb dot org
9 years ago
Actually, this version is better than the last I submitted.  The goal here is to be able to engage in *multiple* delimeter removal passes; for all but the last pass, set the third value to "1", and everything should go well.

    function quotesplit( $splitter=',', $s, $restore_quotes=0 )
    {
        //First step is to split it up into the bits that are surrounded by quotes
        //and the bits that aren't. Adding the delimiter to the ends simplifies
        //the logic further down

        $getstrings = explode('"', $splitter.$s.$splitter);

        //$instring toggles so we know if we are in a quoted string or not
        $delimlen = strlen($splitter);
        $instring = 0;

        while (list($arg, $val) = each($getstrings))
        {
            if ($instring==1)
            {
                if( $restore_quotes )
                {
                    //Add the whole string, untouched to the previous value in the array
                    $result[count($result)-1] = $result[count($result)-1].'"'.$val.'"';
                } else {
                    //Add the whole string, untouched to the array
                    $result[] = $val;
                }
                $instring = 0;
            }
            else
            {
                //Break up the string according to the delimiter character
                //Each string has extraneous delimiters around it (inc the ones we added
                //above), so they need to be stripped off
                $temparray = split($splitter, substr($val, $delimlen, strlen($val)-$delimlen-$delimlen+1 ) );

                while(list($iarg, $ival) = each($temparray))
                {
                    $result[] = trim($ival);
                }
                $instring = 1;
            }
        }

        return $result;
    }
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1
RE: gcerretini at technica dot net /UTF8
8 years ago
Original problem:
=================

I've try using split function.

<?php
$ferro
="2&#65533;12";
$valore=split("[&#65533;]",$ferro);
echo
$ferro."<br>";
echo
"p1-".$valore[0]."<br>";
echo
"p2-".$valore[1]."<br>";
echo
"p3-".$valore[2]."<br>";
$ferro="2d12";
$valore=split("[d]",$ferro);
echo
$ferro."<br>";
echo
"p1-".$valore[0]."<br>";
echo
"p2-".$valore[1]."<br>";
echo
"p3-".$valore[2]."<br>";
?>

This return:
============

2&#65533;12
p1-2
p2-
p3-12
2d12
p1-2
p2-12
p3-

I use charset UTF-8. When I use char &#65533; the split function ad an empty string between "2" and "12"... Why?

Explanation:
============

UTF-8 charset codes some characters (like the "&#65533;" character) into two bytes. In fact the regular expresion "[&#65533;]" contains 4 bytes (4 non-unicode characters). To demonstrate the real situation I wrote following example:

$ferro="2de12";
$valore=split("[de]",$ferro);
echo $ferro."<br>";
echo "p1-".$valore[0]."<br>";
echo "p2-".$valore[1]."<br>";
echo "p3-".$valore[2]."<br>";

This returns:
=============

2d12
p1-2
p2-
p3-12
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1
franz at fholzinger dot com
8 years ago
The example from ramkumar rajendran did not work.
$line = split("/\n", $input_several_lines_long);
I do not know why this does not work for me.

The following has worked for me to get a maximum of 2 array parts separated by the first new line (independant if saved under UNIX or WINDOWS):
$line = preg_split('/[\n\r]+/',$input_several_lines_long,2);
Also empty lines are not considered here.
up
0
wchris
9 years ago
moritz's quotesplit didn't work for me. It seemed to split on a comma even though it was between a pair of quotes. However, this did work:

function quotesplit($s, $splitter=',')
{
//First step is to split it up into the bits that are surrounded by quotes and the bits that aren't. Adding the delimiter to the ends simplifies the logic further down

    $getstrings = split('\"', $splitter.$s.$splitter);

//$instring toggles so we know if we are in a quoted string or not
    $delimlen = strlen($splitter);
    $instring = 0;

    while (list($arg, $val) = each($getstrings))
    {
        if ($instring==1)
        {
//Add the whole string, untouched to the result array.
            $result[] = $val;
            $instring = 0;
        }
        else
        {
//Break up the string according to the delimiter character
//Each string has extraneous delimiters around it (inc the ones we added above), so they need to be stripped off
            $temparray = split($splitter, substr($val, $delimlen, strlen($val)-$delimlen-$delimlen ) );

            while(list($iarg, $ival) = each($temparray))
            {
                $result[] = trim($ival);
            }
            $instring = 1;
        }
    }
    return $result;
}
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0
alphibia at alphibia dot com
10 years ago
I'd like to correct myself, I found that after testing my last solution it will create 5 lines no matter what... So I added this to make sure that it only displays 5 if there are five newlines. :-)

<?php
    $MaxNewLines
= 5;

   
$BRCount = substr_count($Message, '<br />'); 
    if (
$BRCount<$MaxNewLines)
   
$MaxNewLines=$BRCount;
    else if(
$BRCount == 0)
   
$MaxNewLines=1;

   
$Message = str_replace(chr(13), "<br />", $Message);
   
$MessageArray = split("<br />", $Message, $MaxNewLines);
   
$Message = ""; $u=0;
    do    {
   
$Message.=$MessageArray[$u].'<br />';
   
$u++;
    } while(
$u<($MaxNewLines-1));
   
$Message.=str_replace("<br />"," ",$MessageArray[$u]);
   
?>

-Tim
http://www.alphibia.com
up
0
jeffrey at jhu dot edu
11 years ago
In answer to gwyne at gmx dot net, dec 1, 2002:

For split(), when using a backslash as the delimiter, you have to *double escape* the backslash.

example:
==================================
<pre>
<?
$line
= 'stuff\\\thing\doodad\\';
$linearray = split('\\\\', $line); //<--NOTE USE OF FOUR(4)backslashes
print join(":", $linearray);
?>
</pre>

==================================
output is:

<pre>
stuff::thing:doodad:
</pre>
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0
fotw at gmx dot net
12 years ago
Ups! It seems that neither explode nor split REALY takes a STRING but only a single character as a string for splitting the string.
I found this problem in one of my codes when trying to split a string using ";\n" as breaking string. The result, only ";" was thaken... the rest of the string was ignored.
Same when I tried to substitute "\n" by any other thing. :(
up
0
not at anythingspecial dot com
12 years ago
If you need to do a split on a period make sure you escape the period out..

$ext_arr = split("\.","something.jpg");
... because
$ext_arr = split(".","something.jpg"); won't work properly.
up
0
jchart at sdccu dot net
12 years ago
[Ed. note: Close. The pipe *is* an operator in PHP, but
the reason this fails is because it's also an operator
in the regex syntax. The distinction here is important
since a PHP operator inside a string is just a character.]

The reason your code:

$line = "12|3|Fred";
list ($msgid, $msgref, $msgtopic)=split('|', $line);

didn't work is because the "|" symbol is an operator in PHP. If you want to use the pipe symbol as a delimiter you must excape it with a back slash, "\|". You code should look like this:

$line = "12|3|Fred";
list ($msgid, $msgref, $msgtopic)=split('\|', $line);
up
-1
nomail at please dot now
10 years ago
If you want to use split to check on line feeds (\n), the following won't work:

$line = split("\n", $input_several_lines_long);

You really have to do this instead, notice the second slash:
$line = split("\\n", $input_several_lines_long);

Took me a little while to figure out.
up
-1
dalu at uni dot de
11 years ago
php4.3.0

strange things happen with split

this didn't work
$vontag $vonmonat were empty strings

<?php
function ckdate($fromdate="01.01", $todate="31.12")
{
   
$nowyear = date("Y");
    list (
$vontag , $vonmonat) = split ('.' , $fromdate); // << bad
   
$vondatum = "$nowyear-$vonmonat-$vontag";
    list (
$bistag , $bismonat) = split ('.' , $todate); // << bad
   
$bisdatum = "$nowyear-$bismonat-$bistag";
   
$von = strtotime($vondatum);
   
$bis = strtotime($bisdatum);
   
$now = time();
    if ((
$now <= $bis) and ($now >= $von))
    {
        return
TRUE;
    }
    else
    {
        return
FALSE;
    }
}
?>

however this one worked perfectly

<?php
function ckdate($fromdate="01.01", $todate="31.12")
{
   
$nowyear = date("Y");
    list (
$vontag , $vonmonat) = split ('[.]' , $fromdate); // << good
   
$vondatum = "$nowyear-$vonmonat-$vontag";
    list (
$bistag , $bismonat) = split ('[.]' , $todate); // << good
   
$bisdatum = "$nowyear-$bismonat-$bistag";
   
$von = strtotime($vondatum);
   
$bis = strtotime($bisdatum);
   
$now = time();
    if ((
$now <= $bis) and ($now >= $von))
    {
        return
TRUE;
    }
    else
    {
        return
FALSE;
    }
}
?>

btw this fn checks if $now if between $fromdate and $todate
use it if you like
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-1
paha at paha dot hu
12 years ago
It's evident but not mentioned in the documentation that using asterisks is more restricted than in a normal regular expression.

for exaple you cannot say:

split(";*",$string);

because what if there's no ";" separator?(which is covered by this regular expression)

so you have to use at least

split(";+",$quotatxt);

in this situation.
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-1
kang at elpmis dot com
12 years ago
This is a good way to display a comma delimited file with two columns.  The first column is the URL's description, the second is the actual URL.

<ul>
<?php
  $fname
="relatedlinks.csv";
 
$fp=fopen($fname,"r") or die("Error found.");
 
$line = fgets( $fp, 1024 );
  while(!
feof($fp))
  {
    list(
$desc,$url,$dummy) = split( ",", $line, 3 );
    print
"<li>";
    print
"<a href='$url'>$desc</a>";
    print
"</li>\n";
   
$line = fgets( $fp, 1024 );
  }
 
fclose($fp);
?>
</ul>
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-1
mcgarry at tig dot com dot au
12 years ago
split() doesn't like NUL characters within the string, it treats the first one it meets as the end of the string, so if you have data you want to split that can contain a NUL character you'll need to convert it into something else first, eg:

$line=str_replace(chr(0),'',$line);
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-1
Chris Tyler
6 years ago
Thank you Dave for your code below.  Here is one change I made to avoid a redundant quote at the end of some lines (at least when I used excel: 

Added another --length;  into the if statement below:

                // Is the last thing a quote?
                if ($trim_quote){
                    // Well then get rid of it
                    --$length;
        // ADD TO FIX extra quote
    --$length;
                }
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-1
lewis [ at t] hcoms [d dot t] co [d dot t] uk
6 years ago
Those of you trying to use split for CSV, it won't always work as expected. Instead, try using a simple stack method:

<?php

   
/**
     * Create a 2D array from a CSV string
     *
     * @param mixed $data 2D array
     * @param string $delimiter Field delimiter
     * @param string $enclosure Field enclosure
     * @param string $newline Line seperator
     * @return
     */
   
function parse($data, $delimiter = ',', $enclosure = '"', $newline = "\n"){
       
$pos = $last_pos = -1;
       
$end = strlen($data);
       
$row = 0;
       
$quote_open = false;
       
$trim_quote = false;

       
$return = array();

       
// Create a continuous loop
       
for ($i = -1;; ++$i){
            ++
$pos;
           
// Get the positions
           
$comma_pos = strpos($data, $delimiter, $pos);
           
$quote_pos = strpos($data, $enclosure, $pos);
           
$newline_pos = strpos($data, $newline, $pos);

           
// Which one comes first?
           
$pos = min(($comma_pos === false) ? $end : $comma_pos, ($quote_pos === false) ? $end : $quote_pos, ($newline_pos === false) ? $end : $newline_pos);

           
// Cache it
           
$char = (isset($data[$pos])) ? $data[$pos] : null;
           
$done = ($pos == $end);

           
// It it a special character?
           
if ($done || $char == $delimiter || $char == $newline){

               
// Ignore it as we're still in a quote
               
if ($quote_open && !$done){
                    continue;
                }

               
$length = $pos - ++$last_pos;

               
// Is the last thing a quote?
               
if ($trim_quote){
                   
// Well then get rid of it
                   
--$length;
                }

               
// Get all the contents of this column
               
$return[$row][] = ($length > 0) ? str_replace($enclosure . $enclosure, $enclosure, substr($data, $last_pos, $length)) : '';

               
// And we're done
               
if ($done){
                    break;
                }

               
// Save the last position
               
$last_pos = $pos;

               
// Next row?
               
if ($char == $newline){
                    ++
$row;
                }

               
$trim_quote = false;
            }
           
// Our quote?
           
else if ($char == $enclosure){

               
// Toggle it
               
if ($quote_open == false){
                   
// It's an opening quote
                   
$quote_open = true;
                   
$trim_quote = false;

                   
// Trim this opening quote?
                   
if ($last_pos + 1 == $pos){
                        ++
$last_pos;
                    }

                }
                else {
                   
// It's a closing quote
                   
$quote_open = false;

                   
// Trim the last quote?
                   
$trim_quote = true;
                }

            }

        }

        return
$return;
    }

?>

This *should* work for any valid CSV string, regardless of what it contains inside its quotes (using RFC 4180). It should also be faster than most of the others I've seen. It's very simple in concept, and thoroughly commented.
up
-2
pascalaschwandenNOSPAM at gmail dot com
6 years ago
The following code will mimick the explode functionality: explode( " ", $s );  The difference, of course, is that the split method takes a regular expression instead of a string.

$s = "Split this sentence by spaces";
$words = split("[ ]+", $s);
print_r($words);

Output:
Array
(
    [0] => Split
    [1] => this
    [2] => sentence
    [3] => by
    [4] => spaces
)
http://www.codesplunk.com/nr/questions/php12.html
up
-2
ramkumar rajendran
9 years ago
A correction to a earlier note
If you want to use split to check on line feeds (\n), the following won't work:

$line = split("\n", $input_several_lines_long);

You really have to do this instead, notice the second slash:
$line = split("/\n", $input_several_lines_long);

Took me a little while to figure to do
up
-1
robin at teddyb dot org
9 years ago
wchris's quotesplit assumes that anything that is quoted must also be a complete delimiter-seperated entry by itself.  This version does not.  It also uses split's argument order.

    function quotesplit( $splitter=',', $s )
    {
        //First step is to split it up into the bits that are surrounded by quotes
        //and the bits that aren't. Adding the delimiter to the ends simplifies
        //the logic further down

        $getstrings = explode('"', $splitter.$s.$splitter);

        //$instring toggles so we know if we are in a quoted string or not
        $delimlen = strlen($splitter);
        $instring = 0;

        while (list($arg, $val) = each($getstrings))
        {
            if ($instring==1)
            {
                //Add the whole string, untouched to the previous value in the array
                $result[count($result)-1] = $result[count($result)-1].$val;
                $instring = 0;
            }
            else
            {
                //Break up the string according to the delimiter character
                //Each string has extraneous delimiters around it (inc the ones we added
                //above), so they need to be stripped off
                $temparray = split($splitter, substr($val, $delimlen, strlen($val)-$delimlen-$delimlen+1 ) );

                while(list($iarg, $ival) = each($temparray))
                {
                    $result[] = trim($ival);
                }
                $instring = 1;
            }
        }

        return $result;
    }
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-1
claes at dot2me.com
9 years ago
Though this is obvious, the manual is a bit incorrect when claiming that the return will always be 1+number of time the split pattern occures.  If the split pattern is the first part of the string, the return will still be 1.  E.g.

$a = split("zz," "zzxsj.com");
count($a);

=> 1.

The return of this can not in anyway be seperated from the return where the split pattern is not found.
up
-1
krahn at niehs dot nih dot gov
10 years ago
> strange things happen with split
> this didn't work
> $vontag $vonmonat were empty strings
...
> list ($vontag , $vonmonat) = split ('.' , $fromdate); // << bad

Split is acting exactly as it should; it splits on regular expressions.
A period is a regular expression pattern for a single character.
So, an actual period must be escaped with a backslash:  '\.'
A period within brackets is not an any-character pattern, because it does
not make sense in that context.

Beware that regular expressions can be confusing becuase there
are a few different varieties of patterns.
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-2
Greg Levine
5 years ago
I kept running into the same issue Chris Tyler experienced with lewis [ at t] hcoms [d dot t] co [d dot t] uk's function before realizing that Chris had come up with a solution. However, that solution was just a little off it seems, unless your CSV only contains one line.

If you simply add another --length; in the place you suggested, then the function will always trim the last two characters on the line. Since the newline character is the last character on the line and the redundant quote (or other enclosure) is the second to last character, this works for the final segment. But when parsing segments that do not include a newline character, you end up trimming the redundant enclosure and the last character before the enclosure.

For example,

"he","she","him","her"\r\n

becomes

[0] => h
[1] => sh
[2] => hi
[3] => her

Since the segment could end with the enclosure (i.e., ") or the enclosure followed by the newline (i.e., "\r\n), you have make sure you are only adding another --length; when the latter is the case. Replacing the code block that you suggested with the following will do the trick.

# Is the last thing a newline?
if( $char == $newline )
{
    # Well then get rid of it
    --$length;
}

# Is the last thing a quote?
if( $trim_quote )
{
    # Well then get rid of it
    --$length;
}

I've tested this only for the purposes of the script I'm working on at this time. So, there could be other bugs I haven't come across, but this seems like the easiest way to eliminate the redundant enclosure.
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-3
Mike
7 years ago
// Split a string into words on boundaries of one or more spaces, tabs or new-lines
$s = "Please cut   \t me \n in pieces";
$words = split("[\n\r\t ]+", $s);
print_r($words);

// Output:
Array
(
    [0] => Please
    [1] => cut
    [2] => me
    [3] => in
    [4] => pieces
)
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