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PHP : Function Reference : String Functions : explode

explode

Split a string by string (PHP 4, PHP 5)
array explode ( string delimiter, string string [, int limit] )

Returns an array of strings, each of which is a substring of string formed by splitting it on boundaries formed by the string delimiter.

Parameters

delimiter

The boundary string.

string

The input string.

limit

If limit is set, the returned array will contain a maximum of limit elements with the last element containing the rest of string.

If the limit parameter is negative, all components except the last -limit are returned.

Although implode() can, for historical reasons, accept its parameters in either order, explode() cannot. You must ensure that the delimiter argument comes before the string argument.

Return Values

If delimiter is an empty string (""), explode() will return FALSE. If delimiter contains a value that is not contained in string, then explode() will return an array containing string.

ChangeLog

Version Description
5.1.0 Support for negative limits was added
4.0.1 The limit parameter was added

Examples

Example2407.explode() examples

<?php
// Example 1
$pizza = "piece1 piece2 piece3 piece4 piece5 piece6";
$pieces = explode(" ", $pizza);
echo
$pieces[0]; // piece1
echo $pieces[1]; // piece2

// Example 2
$data = "foo:*:1023:1000::/home/foo:/bin/sh";
list(
$user, $pass, $uid, $gid, $gecos, $home, $shell) = explode(":", $data);
echo
$user; // foo
echo $pass; // *

?>


Example2408.limit parameter examples

<?php
$str
= 'one|two|three|four';

// positive limit
print_r(explode('|', $str, 2));

// negative limit (since PHP 5.1)
print_r(explode('|', $str, -1));
?>

The above example will output:

Array
(
[0] => one
[1] => two|three|four
)
Array
(
[0] => one
[1] => two
[2] => three
)


Notes

Note:

This function is binary-safe.

Related Examples ( Source code ) » explode















Code Examples / Notes » explode

tajhlande

While trying to use explode() to parse CSV formatted lines output by MS Excel, I found that if cells contained a comma, then explode() would not behave as desired.  So I wrote the following function, which obeys the double quote escaping format output by Excel.  Note that it is not sophisticated enough to handle delimiters or escapes that consist of more than one character.  I also have no idea how this code will perform when subjected to Unicode data.  Use at your own risk.
<?php
// splits a string into an array of tokens, delimited by delimiter char
// tokens in input string containing the delimiter character or the literal escape character are surrounded by a pair of escape characteres
// a literal escape character is produced by the escape character appearing twice in sequence
// default delimiter character and escape character are suitable for Excel-exported CSV formatted lines
function splitWithEscape ($str, $delimiterChar = ',', $escapeChar = '"') {
   $len = strlen($str);
   $tokens = array();
   $i = 0;
   $inEscapeSeq = false;
   $currToken = '';
   while ($i < $len) {
       $c = substr($str, $i, 1);
       if ($inEscapeSeq) {
           if ($c == $escapeChar) {
               // lookahead to see if next character is also an escape char
               if ($i == ($len - 1)) {
                   // c is last char, so must be end of escape sequence
                   $inEscapeSeq = false;
               } else if (substr($str, $i + 1, 1) == $escapeChar) {
                   // append literal escape char
                   $currToken .= $escapeChar;
                   $i++;
               } else {
                   // end of escape sequence
                   $inEscapeSeq = false;
               }
           } else {
               $currToken .= $c;
           }
       } else {
           if ($c == $delimiterChar) {
               // end of token, flush it
               array_push($tokens, $currToken);
               $currToken = '';
           } else if ($c == $escapeChar) {
               // begin escape sequence
               $inEscapeSeq = true;
           } else {
               $currToken .= $c;
           }
       }
       $i++;
   }
   // flush the last token
   array_push($tokens, $currToken);
   return $tokens;
}
?>


kevin

We've written a function: explodeTree() that can explode any single-dimensional array into a full blown tree. The function uses a user-specified delimiter found in the keys of the original array to separate nodes and determine hierarchy.
Sample: with 3 lines of code you could have a full directory hierarchy in a multi-dimensional array if you specify the delimiter to be a '/' (slash).
I'm posting a link because the function is being improved by site visitors commenting on the article:
http://kevin.vanzonneveld.net/techblog/article/72/


tobylewis

Watch out for this gottcha.  Consider:
$arr = explode("/", "");
This should return a null array (ie count($arr) == 0).  
Array
(
)
However, explode will instead return an array of one item which is a null string.
Array
(
   [0] =>
)
There is some logic to the way this works but consider  the following:
$addressees = "email@domain1.com, email@domain2.com";
$arr = explode(",", $addressees);
foreach($arr AS $to) mail ($to, $subject, $message);
with two items in the list it would sent two separate emails, with one it would sent one email message but with $addressees = "" it will still attempt to send one message that will fail because instead of returning an empty array explode returns an array with an empty item.


coroa

To split a string containing multiple seperators between elements rather use preg_split than explode:
preg_split ("/\s+/", "Here  are    to    many  spaces in   between");
which gives you
array ("Here", "are", "to", "many", "spaces", "in", "between");


thomas

This had me for a moment. A quick gotcha, for me, because it was causing some problems in a script of mine.
If you explode an empty string, you'll get an array with one element - an empty string, and not an empty array or string as you may think.
For example:
<?php
$string = "";
$numbers = explode(",", $string); // Array with one element, "".
$string = "1,2,3";
$numbers = explode(",", $string); // Array with three elements
?>


q1712

some more notes on the delimiter:
if the delimiter is 0, explode will return an array with one element containig the hole string (same as if the delimiter was 1).
if a negative delimiter is bigger or equal to the number of components, an empty array is returned.
<?php
print_r( explode( "|", "one|two|three|four", 0) );
print_r( explode( "|", "one|two|three|four", 1) );
?>
both print:
Array
(
   [0] => one|two|tree|four
)
<?php
print_r( explode( "|", "one|two|three|four", -4) );
print_r( explode( "|", "one|two|three|four", -5) );
?>
both print:
Array
(
)


seventoes

Note that explode, split, and functions like it, can accept more than a single character for the delimiter.
<?php
$string = "Something--next--something else--next--one more";
print_r(explode('--next--',$string));
?>


jj rock

Just a quick note to compliment jason dot minett's comment a few down:
It's obvious that this works the opposite way as well:
<?php
$str = "^one^two^three";
$arr = explode ("^", $str);
?>
results in an empty value in $arr[0].


nicoxinchao

insensitive case explode function:
<?php
function iExplode($Delimiter, $String, $Limit = '')
{
$Explode = array();
$LastIni = 0;
$Count   = 1;

if (is_numeric($Limit) == false)
$Limit = '';
while ( false !== ( $Ini = stripos($String, $Delimiter, $LastIni) ) && ($Count < $Limit || $Limit == ''))
{
$Explode[] = substr($String, $LastIni, $Ini-$LastIni);
$LastIni = $Ini+strlen($Delimiter);
$Count++;
}

$Explode[] = substr($String, $LastIni);
return $Explode;
}
?>


webmaster

If you want to split a price (float) into pounds and pence.
or dollors and cents etc etc.
$price = "6.20";
$split = explode(".", $price);
$pound = $split[0]; // piece1
$pence = $split[1]; // piece2
echo "&pound $pound . $pence\n";


ian

If you split an empty string, you get back a one-element array with 0 as the key and an empty string for the value.
<?php
$str = '';
$foo = explode( ":", $str );
print_r( $foo );
$foo = split( ":", $str );
print_r( $foo );
$foo = preg_split( "/:/", $str );
print_r( $foo );
?>
In all three cases prints
Array
(
    [0] =>
)
This of course means that you must explicitly check to see if the value of the first element is blank, or must check to see if the string being split is blank.


pinkgothic

coroa at cosmo-genics dot com mentioned using preg_split() instead of explode() when you have multiple delimiters in your text and don't want your result array cluttered with empty elements. While that certainly works, it means you need to know your way around regular expressions... and, as it turns out, it is slower than its alternative. Specifically, you can cut execution time roughly in half if you use array_filter(explode(...)) instead.
Benchmarks (using 'too many spaces'):
Looped 100000 times:
preg_split: 1.61789011955 seconds
filter-explode: 0.916578054428 seconds
Looped 10000 times:
preg_split: 0.162719011307 seconds
filter-explode: 0.0918920040131 seconds
(The relation is, evidently, pretty linear.)
Note: Adding array_values() to the filter-explode combination, to avoid having those oft-feared 'holes' in your array, doesn't remove the benefit, either. (For scale - the '9' becomes a '11' in the benchmarks above.)
Also note: I haven't tested anything other than the example with spaces - since djogo_curl at yahoo's note seems to imply that explode() might get slow with longer delimiters, I expect this would be the case here, too.
I hope this helps someone. :)


djogo_curl

Being a beginner in php but not so in Perl, I was used to split() instead of explode(). But as split() works with regexps it turned out to be much slower than explode(), when working with single characters.

jason dot minett

A quick gotcha that had me head scratching for a while....
If the delimiter occurs right at the end of the string there will be an extra array element (an empty string):
<?php
$str = "aaa^elephant^chocolate^albatross^";
$arr = explode ("^", $str);
echo ("Array length: ".count($arr));
?>
---------------------------------
Array length: 5


orlandu96

A 'between' function that we've all been waiting for. I am not savvy with regex so I resorted to explode();
<?php
function between($beg, $end, $str) {
$a = explode($beg, $str, 2);
$b = explode($end, $a[1]);
return $beg . $b[0] . $end;
}
echo between('<a>', '</a>', 'fsdfsdfsd<a>fsdfsd<a><a></a>sdfsdfsdf')
//<a>fsdfsd<a><a></a>
?>


ianb

@ tobylewis
No, it should not return a null array! The description clearly states: If delimiter contains a value that is not contained in string, then explode() will return an array containing string.
So it returns an array containing the original (empty) string.
Wouldn't you test for an invalid email address before trying to mail to it anyway? :S


xangelusx

@ JJ Rock, jason dot minett:
Here's an easy way around that:
<?php
$str = '^one^two^three^';
//Use trim() to remove extra delimiters
$arr = explode ('^', trim($str, '^'));
?>


elad elrom

// simple function to remove words if more than max allowed words or add a charcter once less than min
// Example: LimitText("The red dog ran out of thefence",15,20,"
");
function LimitText($Text,$Min,$Max,$MinAddChar) {
if (strlen($Text) < $Min) {
$Limit = $Min-strlen($Text);
$Text .= $MinAddChar;
}
elseif (strlen($Text) >= $Max) {
$words = explode(" ", $Text);
$check=1;
while (strlen($Text) >= $Max) {
$c=count($words)-$check;
$Text=substr($Text,0,(strlen($words[$c])+1)*(-1));
$check++;
}
}

return $Text;
}


user

<?php
// returns a string where $variables are replaced with their global value if available; removes all extra whitespaces
function evaluateString($string) {
 if ($string) {  // check for value
   $array = explode(' ', $string);  // split into parts
   foreach ($array as $word) {  // each part
     if ($word[0] == '$') {  // is part a variable
       if ($word = substr($word, 1)) {  // get variable name
         global ${$word};  // retrieve global value
         $html .= ${$word};  // add value to string
       }  // end variable name check
     } else {  // not a variable
       $html .= $word;  // add word to string
     }  // end variable check
     $html .= ' ';  // add space between words
   }  // end part loop
 }  // end string check
 return trim($html);  // trims final space from end
}  // end evaluateString
?>


mraheel83

<?php
$query = "SELECT * FROM `orders_status` Where status = 'enabled'";  
$result = mysql_query($query);  
$counter = 0;
$orderStatusRecords = explode(",",$_REQUEST['orderStatus']);

while($row = mysql_fetch_array($result)) {
echo $orderStatusRecords[$counter];
?>
<input type="checkbox" name="chkOrderStatus[]" value="<?=$row['id']?>" <?php if($row['id'] == $orderStatusRecords[$counter]) {?> checked="checked" <?php } ?> /> <?=$row['title']?> &nbsp;
<?php $counter++;
} ?>
You can checked selected checkbox by using above explode + while loop combination


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