Explode string into array with no empty elements? - php

Question

PHP's explode function returns an array of strings split on some provided substring. It will return empty strings when there are leading, trailing, or consecutive delimiters, like this:
var_dump(explode('/', '1/2//3/'));
array(5) {
[0]=>
string(1) "1"
[1]=>
string(1) "2"
[2]=>
string(0) ""
[3]=>
string(1) "3"
[4]=>
string(0) ""
}
Is there some different function or option or anything that would return everything except the empty strings?
var_dump(different_explode('/', '1/2//3/'));
array(3) {
[0]=>
string(1) "1"
[1]=>
string(1) "2"
[2]=>
string(1) "3"
}

Answer 1

Try preg_split.
$exploded = preg_split('#/#', '1/2//3/', -1, PREG_SPLIT_NO_EMPTY);

Answer 2

array_filter will remove the blank fields, here is an example without the filter:
print_r(explode('/', '1/2//3/'))
prints:
Array
(
[0] => 1
[1] => 2
[2] =>
[3] => 3
[4] =>
)
With the filter:
php> print_r(array_filter(explode('/', '1/2//3/')))
Prints:
Array
(
[0] => 1
[1] => 2
[3] => 3
)
You'll get all values that resolve to "false" filtered out.
see http://uk.php.net/manual/en/function.array-filter.php

Answer 3

Just for variety:
array_diff(explode('/', '1/2//3/'), array(''))
This also works, but does mess up the array indexes unlike preg_split. Some people might like it better than having to declare a callback function to use array_filter.

Answer 4

function not_empty_string($s) {
return $s !== "";
}
array_filter(explode('/', '1/2//3/'), 'not_empty_string');

Answer 5

I have used this in TYPO3, look at the $onlyNonEmptyValues parameter:
function trimExplode($delim, $string, $onlyNonEmptyValues=0){
$temp = explode($delim,$string);
$newtemp=array();
while(list($key,$val)=each($temp)) {
if (!$onlyNonEmptyValues || strcmp("",trim($val))) {
$newtemp[]=trim($val);
}
}
reset($newtemp);
return $newtemp;
}
It doesn't mess up the indexes:
var_dump(trimExplode('/', '1/2//3/',1));
Result:
array(3) {
[0]=>
string(1) "1"
[1]=>
string(1) "2"
[2]=>
string(1) "3"
}

Answer 6

Here is a solution that should output a newly indexed array.
$result = array_deflate( explode( $delim, $array) );
function array_deflate( $arr, $emptyval='' ){
$ret=[];
for($i=0,$L=count($arr); $i<$L; ++$i)
if($arr[$i] !== $emptyval) $ret[]=$arr[$i];
return $ret;
}
While fairly similar to some other suggestion, this implementation has the benefit of generic use. For arrays with non-string elements, provide a typed empty value as the second argument.
array_deflate( $objArray, new stdClass() );
array_deflate( $databaseArray, NULL );
array_deflate( $intArray, NULL );
array_deflate( $arrayArray, [] );
array_deflate( $assocArrayArray, [''=>NULL] );
array_deflate( $processedArray, new Exception('processing error') );
.
.
.
With an optional filter argument..
function array_deflate( $arr, $trigger='', $filter=NULL, $compare=NULL){
$ret=[];
if ($filter === NULL) $filter = function($el) { return $el; };
if ($compare === NULL) $compare = function($a,$b) { return $a===$b; };
for($i=0,$L=count($arr); $i<$L; ++$i)
if( !$compare(arr[$i],$trigger) ) $ret[]=$arr[$i];
else $filter($arr[$i]);
return $ret;
}
With usage..
function targetHandler($t){ /* .... */ }
array_deflate( $haystack, $needle, targetHandler );
Turning array_deflate into a way of processing choice elements and removing them from your array. Also nicer is to turn the if statement into a comparison function that is also passed as an argument in case you get fancy.
array_inflate being the reverse, would take an extra array as the first parameter which matches are pushed to while non-matches are filtered.
function array_inflate($dest,$src,$trigger='', $filter=NULL, $compare=NULL){
if ($filter === NULL) $filter = function($el) { return $el; };
if ($compare === NULL) $compare = function($a,$b) { return $a===$b; };
for($i=0,$L=count($src); $i<$L; ++$i)
if( $compare(src[$i],$trigger) ) $dest[]=$src[$i];
else $filter($src[$i]);
return $dest;
}
With usage..
$smartppl=[];
$smartppl=array_inflate( $smartppl,
$allppl,
(object)['intelligence'=>110],
cureStupid,
isSmart);
function isSmart($a,$threshold){
if( isset($a->intellgence) ) //has intelligence?
if( isset($threshold->intellgence) ) //has intelligence?
if( $a->intelligence >= $threshold->intelligence )
return true;
else return INVALID_THRESHOLD; //error
else return INVALID_TARGET; //error
return false;
}
function cureStupid($person){
$dangerous_chemical = selectNeurosteroid();
applyNeurosteroid($person, $dangerous_chemical);
if( isSmart($person,(object)['intelligence'=>110]) )
return $person;
else
lobotomize($person);
return $person;
}
Thus providing an ideal algorithm for the world's educational problems. Aaand I'll stop there before I tweak this into something else..

Answer 7

Write a wrapper function to strip them
function MyExplode($sep, $str)
{
$arr = explode($sep, $str);
foreach($arr as $item)
if(item != "")
$out[] = $item;
return $out;
}

Answer 8

Use this function to filter the output of the explode function
function filter_empty(&$arrayvar) {
$newarray = array();
foreach ($arrayvar as $k => $value)
if ($value !== "")
$newarray[$k] = $value;
$arrayvar = $newarray;
}

Answer 9

Regular expression solutions tend to be much slower than basic text replacement, so i'd replace double seperators with single seperators, trim the string of any whitespace and then use explode:
// assuming $source = '1/2//3/';
$source = str_replace('//', '/', $source);
$source = trim($source);
$parts = explode('/', $source);

Answer 10

No regex overhead - should be reasonably efficient, strlen just counts the bytes
Drop the array_values() if you don't care about indexes
Make it into function explode_interesting( $array, $fix_index = 0 ) if you want
$interesting = array_values(
array_filter(
explode('/', '/1//2//3///4/0/false' ),
function ($val) { return strlen($val); }
));
echo "<pre>", var_export( $interesting, true ), "</pre>";
enjoy, Jeff

Answer 11

PHP's split function is similar to the explode function, except that it allows you to enter a regex pattern as the delimiter. Something to the effect of:
$exploded_arr = split('/\/+/', '1/2//3/');

Answer 12

I usually wrap it in a call to array_filter, e.g.
var_dump(array_filter(explode('/', '1/2//3/'))
=>
array(3) {
[0]=>
string(1) "1"
[1]=>
string(1) "2"
[3]=>
string(1) "3"
}
Be aware, of course, that array keys are maintained; if you don't want this behaviour, remember to add an outer wrapper call to array_values().