php教程

explode

(PHP 4, PHP 5, PHP 7)

explode使用一个字符串分割另一个字符串

说明

explode ( string $delimiter , string $string [, int $limit ] ) : array

此函数返回由字符串组成的数组,每个元素都是 string 的一个子串,它们被字符串 delimiter 作为边界点分割出来。

参数

delimiter

边界上的分隔字符。

string

输入的字符串。

limit

如果设置了 limit 参数并且是正数,则返回的数组包含最多 limit 个元素,而最后那个元素将包含 string 的剩余部分。

如果 limit 参数是负数,则返回除了最后的 -limit 个元素外的所有元素。

如果 limit 是 0,则会被当做 1。

由于历史原因,虽然 implode() 可以接收两种参数顺序,但是 explode() 不行。你必须保证 separator 参数在 string 参数之前才行。

返回值

此函数返回由字符串组成的 array,每个元素都是 string 的一个子串,它们被字符串 delimiter 作为边界点分割出来。

如果 delimiter 为空字符串(""),explode() 将返回 FALSE。 如果 delimiter 所包含的值在 string 中找不到,并且使用了负数的 limit , 那么会返回空的 array, 否则返回包含 string 单个元素的数组。

更新日志

版本 说明
5.1.0 支持负数的 limit
4.0.1 增加了参数 limit

范例

Example #1 explode() 例子

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

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

?>

Example #2 explode() return examples

<?php
/* A string that doesn't contain the delimiter will simply return a one-length array of the original string. */
$input1 "hello";
$input2 "hello,there";
var_dumpexplode','$input1 ) );
var_dumpexplode','$input2 ) );

?>

以上例程会输出:

array(1)
(
    [0] => string(5) "hello"
)
array(2)
(
    [0] => string(5) "hello"
    [1] => string(5) "there"
)

Example #3 limit 参数的例子

<?php
$str 
'one|two|three|four';

// 正数的 limit
print_r(explode('|'$str2));

// 负数的 limit(自 PHP 5.1 起)
print_r(explode('|'$str, -1));
?>

以上例程会输出:

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

注释

Note: 此函数可安全用于二进制对象。

参见

User Contributed Notes

rs at income dot cz 13-Aug-2019 08:25
explode(' ','') returns nonempty array ...
jaybee at baelemans dot eu 06-Jun-2019 04:55
It toke me about 1 day to find out the problem. (almost?) every function in PHP has a logical build as argument 1: Entity where the operation is based upon and 2 - the operand in the process. But with the explode-function the order is reversed and different. First the operand (delimiter) and second the string to be managed. Not quite logical compared to other needle-haystack-functions. And yes, If you're reading the format it should be no problem. Just hoping to help somebody else.
Grihais Modoravko 06-Jun-2019 12:52
<?php
functinon metaExplode
(string $za = '', string $lu = '', string $pa = '') {
    return
explode($za . ',' . $lu . ',' . $pa, ',');
}
jenny 26-Mar-2018 02:30
He found that the white girl's lame leg and chose to break up was actually broken up. If it weren't for her pregnant with her children, he did not have a compound chance. When this opportunity arises, what he thinks is not Green Hat shame http://www.verobuddismo.ru/
KEINOS 19-Jan-2018 07:52
If you want to have delimiter option as an array WITH limit option.
( an extended approach from php-at-metehanarslan-dot-com's )

<?php
/**
 * explode_multi function.
 *
 * Split a string by an array of string and limitable
 *
 * @access public
 * @param  array    $delimiters
 * @param  string   $string_raw
 * @param  integer  $limit (default: PHP_INT_MAX)
 * @return array
 */
function explode_multi($delimiters, $string_raw, $limit = PHP_INT_MAX)
{
   
$string_tmp = (string) $string_raw;
   
$string_rep = str_replace($delimiters, $delimiters[0], $string_raw);
   
$exploded   = explode($delimiters[0], $string_rep, $limit);
   
$result     = array();
    for (
$key = 0; $key < ($limit-1); $key++) {
       
$pattern    = $exploded[$key];
       
$string_tmp = preg_replace("/${pattern}/", '', $string_tmp, 1);
       
$result[]   = $pattern;
    }
   
$result[] = trim($string_tmp);

    return
$result;
}

?>
auramgold 27-May-2017 06:58
Simple function to explode a string with keys specified in the string.

<?php
function explode_with_keys($delim1,$delim2,$inputstring)
{
   
$firstarr = explode($delim1,$inputstring);
   
$finalarr = array();
    foreach(
$firstarr as $set)
    {
       
$setarr = explode($delim2,$set);
       
$finalarr[$setarr[0]] = $setarr[1];
    }
    return
$finalarr;
}

print_r(explode_with_keys(";",":","a:b;c:d;e:f"));
?>

Will output:
Array ( [a] => b [c] => d [e] => f )
MarkAgius at markagius dot co dot uk 14-May-2017 10:42
As you can not send an enclosure value to explode, use str_getcsv,
if you want to explode a string when the delimiter is in some cells. (Comma in quotes)

<?php
  $a
= "aaa1,bbb1,'ccc,ccc1',ddd1";
 
$b = 'aaa2,bbb2,"ccc,ccc2",ddd2';

 
// This dosn't work as it splits 'ccc,ccc1' and "ccc,ccc2".

 
print "<PRE>a output using explode():\n";
 
print_r( explode(",",$a) );
  print
"</PRE>\n";

  print
"<PRE>b output using explode():\n";
 
print_r( explode(",",$b) );
  print
"</PRE>\n";

 
// This works.

 
print "<PRE>a output using str_getcsv():\n";
 
print_r( str_getcsv($a,",","'") );
  print
"</PRE>\n";

  print
"<PRE>b output using str_getcsv():\n";
 
print_r( str_getcsv($b,",","\"") );
  print
"</PRE>\n";

?>
explode() returns;
    [0] => aaa1
    [1] => bbb1
    [2] => 'ccc
    [3] => ccc1'
    [4] => ddd1

str_getcsv() returns;
    [0] => aaa1
    [1] => bbb1
    [2] => ccc,ccc1
    [3] => ddd1
Manngo 30-Dec-2016 07:25
Sometimes I want to create a MINIMUM length array. For example, if the delimiter is not present at all, you might still want an empty additional item.

This can be done by adding the delimiter to the string as follows:

<?php
    $data
='a';
   
$array=explode(':',"$data:");
   
print_r($array);
?>

If you want an EXACT number of elements, you can combine this with array_slice:

<?php
    $data
='a:::';
   
$array=explode(':',"$data:");
   
$array=array_slice($array,0,2);    //    exactly 2 elements
   
print_r($array);
?>
dark dot side01 at yahoo dot com 19-Apr-2016 07:44
(excuse my english)
When I try to use explode to know if a string contains many words, I noticed this :

<?php
      $sentence
= "  word ";
     
$array = explode($sentence);
      
var_dump($array);
?>
return this :

array(4) {
  [0]=>  string(0) ""
  [1]=>  string(0) ""
  [2]=>  string(4) "word"
  [3]=>  string(0) ""
}

So, "explode" didn't keep the delimiter but counts it. You have to use trim($sentence) to count words in a sentence.  ^v^
kenorb at niepodam dot pl 20-Oct-2015 09:48
If you need to split by multiple characters, use preg_split() instead:

    $new_string = preg_split("/[&=:]/", $string);
wado 23-Nov-2014 02:17
It should be said that when an empty delimiter is passed to explode, the function not only will return false but will also emit a warning.

<?php
var_dump
( explode('','asdasd') );

/**
  * Output:
  * Warning: explode(): Empty delimiter in ...
  * bool(false)
  */
?>
david dot drakulovski at gmail dot com 25-Feb-2014 10:58
I made this code for some useful filtering texts with lot of gibberish. Example provided:

<?php
$text
= "There are;many|variations of:passages of Lorem Ipsum available,but the/majority have\"suffered|alteration in some form,by injected humour,or randomised words which don't look even.slightly:believable./";

$delimiter = array(" ",",",".","'","\"","|","\\","/",";",":");
$replace = str_replace($delimiter, $delimiter[0], $text);
$explode = explode($delimiter[0], $replace);

echo
'<pre>';
print_r($explode);
echo
'</pre>';
// replaces many symbols in text, then explodes it
?>

This will output the following:
Array
(
    [0] => There
    [1] => are
    [2] => many
    [3] => variations
    [4] => of
    [5] => passages
    [6] => of
    [7] => Lorem
    [8] => Ipsum
    [9] => available
    [10] => but
    [11] => the
    [12] => majority
    [13] => have
    [14] => suffered
    [15] => alteration
    [16] => in
    [17] => some
    [18] => form
    [19] => by
    [20] => injected
    [21] => humour
    [22] => or
    [23] => randomised
    [24] => words
    [25] => which
    [26] => don
    [27] => t
    [28] => look
    [29] => even
    [30] => slightly
    [31] => believable
    [32] =>
    [33] =>
)
artaxerxes2 at iname dot com 31-Jan-2014 04:29
Note that using explode() on an empty string returns a non-empty array.

So the code:
<?php
  print_r
(explode("|","");
?>
returns:
Array
(
    [0] =>
)

If you need to return an empty array in the case of an empty string, you must call array_diff() after the explode:
<?php
  print_r
(array_diff(explode("|",""),array("")));
?>
returns:
Array
(
)

This is useful in case your use of MySQL's group_concat() returns an empty string for just some records but you want to convert them all to arrays that actually reflect what group_concat() gave you
crog at gustavus dot edu 01-Aug-2013 07:52
Note that while the documentation states the "If limit is set and positive," passing a null-value will still result in triggering the "limit is zero" case (as of PHP 5.4.17).

When passing through values (such as using explode to implement an interface method), you'll need to explicitly check that the limit has been set:

<?php
 
public function split($string, $delimiter, $limit = null)
  {
    return isset(
$limit) ? explode($delimiter, $string, $limit) : explode($delimiter, $string);
  }
?>

Failing to check $limit and simply passing through a null-value will return the same value as if $limit were 0 or 1. To clarify, all of the following will return the same value:

<?php
explode
($string, $delimiter, null);
explode($string, $delimiter, 0);
explode($string, $delimiter, 1);
?>
Hayley Watson 12-Mar-2013 09:13
The comments to use array_filter() without a callback to remove empty strings from explode's results miss the fact that array_filter will remove all elements that, to quote the manual,  "are equal to FALSE".

This includes, in particular, the string "0", which is NOT an empty string.

If you really want to filter out empty strings, use the defining feature of the empty string that it is the only string that has a length of 0. So:
<?php
array_filter
(explode(':', "1:2::3:0:4"), 'strlen');
?>
m.reesinck 18-Feb-2013 12:59
I needed a multiexplode which didn't replace my delimiters for 1 other delimiter. Because I couldn't find one in the examples I made one.

delimiter array:
array('/RTRN/','/BUSP/','/BENM/','/ORDP/','/CSID/', '/MARF/','/EREF/', '/PREF/','/REMI/','/ID/','/PURP/', '/ULTB/','/ULTD/');

input string: /RTRN/MS03//BENM/NL50INGB00012345/BUSP/Europese Incasso/eenmalig/67/INGBNL2A/ING Bank N.V. inzake WeB///CSID/NL32ZZZ999999991234//MARF/EV45451//EREF/EV45451 REP170112T1106//REMI///EV45451REP170112T1106/

output:
array(
[/RTRN/] => MS03/
[/BENM/] => NL50INGB00012345
[/BUSP/] => Europese Incasso/eenmalig/67/INGBNL2A/ING Bank N.V. inzake WeB//
[/CSID/] => NL32ZZZ999999991234/
[/MARF/] => EV45451/
[/EREF/] => EV45451REP170112T1106/
[/REMI/] => //EV45451REP170112T1106/
[/ORDP/] =>
[/PREF/] =>
[/ID/] =>
[/PURP/] =>
[/ULTB/] =>
[/ULTD/] =>
)

<?php
function multiexplode($delimiters,$string) {
           
       
$arrOccurence = array();
       
$arrEnd = array();
        foreach(
$delimiters as $key => $value){
           
$position = strpos($string, $value);
            if(
$position > -1){
               
$arrOccurence[$value] = $position;
            }
        }
       
        if(
count($arrOccurence) > 0){
               
           
asort($arrOccurence);
           
$arrEnd = array_values($arrOccurence);
           
array_shift($arrEnd);
   
           
$i = 0;
            foreach(
$arrOccurence as $key => $start){
               
$pointer = $start+strlen($key);
                if(
$i == count($arrEnd)){
                   
$arrOccurence[$key] = substr($string, $pointer);
                } else {
                   
$arrOccurence[$key] = substr($string, $pointer, $arrEnd[$i]-$pointer);
                }
               
$i++;
            }
           
        }

        
//next part can be left apart if not necessary. In that case key that don't appear in the inputstringwill not be returned
       
foreach($delimiters as $key => $value){
            if(!isset(
$arrOccurence[$value])){
               
$arrOccurence[$value] = '';
            }
        }

        return
$arrOccurence;
}
?>
php at metehanarslan dot com 04-Feb-2013 10:43
Here is my approach to have exploded output with multiple delimiter.

<?php

//$delimiters has to be array
//$string has to be array

function multiexplode ($delimiters,$string) {
   
   
$ready = str_replace($delimiters, $delimiters[0], $string);
   
$launch = explode($delimiters[0], $ready);
    return 
$launch;
}

$text = "here is a sample: this text, and this will be exploded. this also | this one too :)";
$exploded = multiexplode(array(",",".","|",":"),$text);

print_r($exploded);

//And output will be like this:
// Array
// (
//    [0] => here is a sample
//    [1] =>  this text
//    [2] =>  and this will be exploded
//    [3] =>  this also
//    [4] =>  this one too
//    [5] => )
// )

?>
kkobashi at kobashicomputing dot com 14-Jul-2012 03:36
Explode does not parse a string by delimiters, in the sense that we expect to find tokens between a starting and ending delimiter, but instead splits a string into parts by using a string as the boundary of each part. Once that boundary is discovered the string is split. Whether or not that boundary is proceeded or superseded by any data is irrelevant since the parts are determined at the point a boundary is discovered.

For example:

<?php

var_dump
(explode("/","/"));

/*
   Outputs

   array(2) {
     [0]=>
     string(0) ""
     [1]=>
     string(0) ""
   }
*/

?>

The reason we have two empty strings here is that a boundary is discovered before any data has been collected from the string. The boundary splits the string into two parts even though those parts are empty.

One way to avoid getting back empty parts (if you don't care for those empty parts) is to use array_filter on the result.

<?php

var_dump
(array_filter(explode("/","/")));

/*
   Outputs

   array(0) {
   }
*/
?>

*[This note was edited by googleguy at php dot net for clarity]*
eye_syah88 at yahoo dot com 30-May-2011 12:32
a simple one line method to explode & trim whitespaces from the exploded elements

array_map('trim',explode(",",$str));

example:

$str="one  ,two  ,       three  ,  four    ";
print_r(array_map('trim',explode(",",$str)));

Output:

Array ( [0] => one [1] => two [2] => three [3] => four )
dhz 30-Dec-2010 09:21
A one-liner to extract a portion of a string, starting from the END of the string....
<?php
$extracted_string
= implode('.', array_slice(explode('.', $original_string), -2));
?>
tiago dot dias at flow-me dot com 09-Sep-2010 03:40
Beaware splitting empty strings.

<?php
$str
= "";
$res = explode(",", $str);
print_r($res);
?>

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.

Array
(
    [0] =>
)

To solve this, just use array_filter() without callback. Quoting manual page "If the callback function is not supplied, array_filter() will remove all the entries of input that are equal to FALSE.".

<?php
$str
= "";
$res = array_filter(explode(",", $str));
print_r($res);
?>

Array
(
)
Cody G. 08-Aug-2010 06:41
I'm sure you guys get just a bit frustrated at times when you need a fraction of a very simple string and you use "explode()", but then you have to define a whole extra variable. (That is because you need to store a function-returned array in a variable before you can extract a value).

If you're extracting the last half, or third, of a string, there's an easy inline workaround. Check this:

<?php
 $mystr
= "separated-text";
 print(
str_replace("-","",strstr("-",$mystr)));
 
//Returns "text"
?>

If the separator (dash) can be left in, you don't even need the "str_replace()" function.

Lets try this with 3 fractions:

<?php
 $mystr
= "separated-text-again";
 
//Comment submission wouldn't let me
 // combine this into one statement.
 // That's okay, it's more readable.
 
$split1 = str_replace("-","",strstr("-",$mystr));
 print(
str_replace("-","",strstr("-",$split1)));
 
//Returns "again"
?>

Anything more than 3 fractions gets really confusing, in that case you should use "explode()".

Hope this helps!
~Cody G.
m0gr14 at gmail dot com 31-Jul-2010 07:02
Here's a function for "multi" exploding a string.

<?php
//the function
//Param 1 has to be an Array
//Param 2 has to be a String
function multiexplode ($delimiters,$string) {
   
$ary = explode($delimiters[0],$string);
   
array_shift($delimiters);
    if(
$delimiters != NULL) {
        foreach(
$ary as $key => $val) {
            
$ary[$key] = multiexplode($delimiters, $val);
        }
    }
    return 
$ary;
}

// Example of use
$string = "1-2-3|4-5|6:7-8-9-0|1,2:3-4|5";
$delimiters = Array(",",":","|","-");

$res = multiexplode($delimiters,$string);
echo
'<pre>';
print_r($res);
echo
'</pre>';

//returns
/*
Array
(
    [0] => Array
        (
            [0] => Array
                (
                    [0] => Array
                        (
                            [0] => 1
                            [1] => 2
                            [2] => 3
                        )

                    [1] => Array
                        (
                            [0] => 4
                            [1] => 5
                        )

                    [2] => Array
                        (
                            [0] => 6
                        )

                )

            [1] => Array
                (
                    [0] => Array
                        (
                            [0] => 7
                            [1] => 8
                            [2] => 9
                            [3] => 0
                        )

                    [1] => Array
                        (
                            [0] => 1
                        )

                )

        )

    [1] => Array
        (
            [0] => Array
                (
                    [0] => Array
                        (
                            [0] => 2
                        )

                )

            [1] => Array
                (
                    [0] => Array
                        (
                            [0] => 3
                            [1] => 4
                        )

                    [1] => Array
                        (
                            [0] => 5
                        )

                )

        )

)
*/
?>
locoluis at gmail dot com 08-Apr-2010 09:02
That with all stateful encodings that use bytes between 0x00 and 0x7f for something other than, say, encoding ASCII characters. Including GBK, BIG5, Shift-JIS etc.

explode and other such PHP functions work on bytes, not characters.

What you do is to convert the string to UTF-8 using iconv(), then explode, then go back to GBK.
nick dot brown at free dot fr 14-Oct-2009 03:47
My application was running out of memory (my hosting company limits PHP to 32MB).  I have a string containing between 100 and 20000 triplets, separated by a space, with each triplet consisting of three double-precision numbers, separated by commas.  Total size of the biggest string, with 20000 triplets, is about 1MB.

The application needs to split the string into triplets, then split the triplet into numbers.  In C, this would take up about 480K (20000 times 3 x 8 bytes) for the final array.  The intermediate array of strings shouldn't be much bigger than the long string itself (1MB).  And I expect some overhead from PHP, say 300% to allow for indexes etc.

Well, PHP5 manages to run out of memory *at the first stage* (exploding the string on the space character).  I'm expecting to get an array of 20000 strings, but it needs more than 32MB to store it.  Amazing.

The workaround was easy and had the bonus of producing faster code (I compared it on a 10000 triplet string).  Since in any case I had to split up the numeric triplets afterwards, I decided to use preg_match_all() on the original string.  Despite the fact that the resulting "matches" array contains more data per element than the result of explode() - because it stores the matched triplet, plus its component numbers - it takes up far less memory.

Moral: be careful when using explode() on big strings, as it can also explode your memory usage.
Anonymous 28-Sep-2009 03:20
Note to the previous example: we can do the whole string->array conversion using explode() exclusively.

<?php
   
// converts pure string into a trimmed keyed array
   
function string_2_array( $string, $delimiter = ',', $kv = '=>')
    {
        if (
$element = explode( $delimiter, $string ))
        {
           
// create parts
           
foreach ( $element as $key_value )
            {
               
// key -> value pair or single value
               
$atom = explode( $kv, $key_value );

                if(
trim($atom[1]) )
                {
                 
$key_arr[trim($atom[0])] = trim($atom[1]);
                }
                else
                {
                   
$key_arr[] = trim($atom[0]);
                }
            }
        }
        else
        {
           
$key_arr = false;
        }

        return
$key_arr;
    }
?>
Anonymous 02-Sep-2009 07:18
<?php
// converts pure string into a trimmed keyed array
function string2KeyedArray($string, $delimiter = ',', $kv = '=>') {
  if (
$a = explode($delimiter, $string)) { // create parts
   
foreach ($a as $s) { // each part
     
if ($s) {
        if (
$pos = strpos($s, $kv)) { // key/value delimiter
         
$ka[trim(substr($s, 0, $pos))] = trim(substr($s, $pos + strlen($kv)));
        } else {
// key delimiter not found
         
$ka[] = trim($s);
        }
      }
    }
    return
$ka;
  }
}
// string2KeyedArray

$string = 'a=>1, b=>23   , $a, c=> 45% , true,d => ab c ';
print_r(string2KeyedArray($string));
?>

Array
(
  [a] => 1
  [b] => 23
  [0] => $a
  [c] => 45%
  [1] => true
  [d] => ab c
)
SR 21-Apr-2009 07:50
Keep in mind that explode() can return empty elements if the delimiter is immediately repeated twice (or more), as shown by the following example:

<?php
$foo
= 'uno dos  tres'; // two spaces between "dos" and "tres"
print_r(explode(' ', $foo));
?>

Array
(
    [0] => uno
    [1] => dos
    [2] =>
    [3] => tres
)

Needless to say this is definitely not intuitive and must be handled carefully.
seventoes at gmail dot com 09-Dec-2006 07:49
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));
?>
coroa at cosmo-genics dot com 16-Nov-2003 08:01
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");

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