php explode: split string into words by using space a delimiter

Question

$str = "This is a    string";
$words = explode(" ", $str);

Works fine, but spaces still go into array:

$words === array ('This', 'is', 'a', '', '', '', 'string');//true

I would prefer to have words only with no spaces and keep the information about the number of spaces separate.

$words === array ('This', 'is', 'a', 'string');//true
$spaces === array(1,1,4);//true

Just added: (1, 1, 4) means one space after the first word, one space after the second word and 4 spaces after the third word.

Is there any way to do it fast?

Thank you.

http://stackoverflow.com/questions/3432183/how-can-i-remove-all-empty-values-when-i-explode-a-string-using-php — Habib, Sep 05 '13 at 14:23
Do you want the number of spaces or the position of each space? — Jason McCreary, Sep 05 '13 at 14:25
@JasonMcCreary He wants the number of consecutive spaces in each space group: `' ' (1), ' ' (1), ' ' (4)`. — silkfire, Sep 05 '13 at 14:26
@Haradzieniec, I don't think you understand the difference. *Number of spaces* = 6. Which is not what you want. — Jason McCreary, Sep 05 '13 at 15:10
What do you mean "which is not I want"? You are right, the total number of spaces is 6. BUT, I neeed the information about spaces BETWEEN the words. — Haradzieniec, Sep 05 '13 at 15:12
for 1st part of the question, to not consider the spaces just use trim function. — DPC, Feb 02 '15 at 11:30

Alma Do · Accepted Answer · 2015-03-20T08:06:41.583

37

For splitting the String into an array, you should use preg_split:

$string = 'This is a    string';
$data   = preg_split('/\s+/', $string);

Your second part (counting spaces):

$string = 'This is a    string';
preg_match_all('/\s+/', $string, $matches);
$result = array_map('strlen', $matches[0]);// [1, 1, 4]

edited Mar 20 '15 at 08:06

answered Sep 05 '13 at 14:17

Alma Do

37,009
9
76
105

Where is `the number of spaces` about questioner expected? – Bora Sep 05 '13 at 14:19
Thank you for your answer. Howerer, you loose the information about the number of spaces in between. That's what I asked in the question (please see the bolded text). – Haradzieniec Sep 05 '13 at 14:20
@Haradzieniec just typing that, yes. Thanks you, I've updated. – Alma Do Sep 05 '13 at 14:22

score 3 · Answer 2 · answered Sep 05 '13 at 14:30

Here is one way, splitting the string and running a regex once, then parsing the results to see which segments were captured as the split (and therefore only whitespace), or which ones are words:

$temp = preg_split('/(\s+)/', $str, -1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);

$spaces = array();
$words = array_reduce( $temp, function( &$result, $item) use ( &$spaces) {
    if( strlen( trim( $item)) === 0) {
        $spaces[] = strlen( $item);
    } else {
        $result[] = $item;
    }
    return $result;
}, array());

You can see from this demo that $words is:

Array
(
    [0] => This
    [1] => is
    [2] => a
    [3] => string
)

And $spaces is:

Array
(
    [0] => 1
    [1] => 1
    [2] => 4
)

thank you very much for you answer. I've tested both your and Alma Do Mundo / silkfire solutions. All solutions work fine, but Alma Do Mundo's work about two times faster. Thank you for your solution anyway. You can compare both if you want (pleae see my reply on my own question in a second). — Haradzieniec, Sep 05 '13 at 15:06

silkfire · Answer 3 · 2013-09-05T14:27:39.743

1

You can use preg_split() for the first array:

$str   = 'This is a    string';
$words = preg_split('#\s+#', $str);

And preg_match_all() for the $spaces array:

preg_match_all('#\s+#', $str, $m);
$spaces = array_map('strlen', $m[0]);

edited Sep 05 '13 at 14:27

answered Sep 05 '13 at 14:20

silkfire

24,585
15
82
105

1, 1, 4 means one space after the first word, one space after the second word and 4 spaces after the third word. – Haradzieniec Sep 05 '13 at 14:21

score 0 · Answer 4 · answered Sep 05 '13 at 14:22

0

Another way to do it would be using foreach loop.

$str = "This is a    string";
$words = explode(" ", $str);
$spaces=array();
$others=array();
foreach($words as $word)
{
if($word==' ')
{
array_push($spaces,$word);
}
else
{
array_push($others,$word);
}
}

answered Sep 05 '13 at 14:22

Ahmar Ali

1,038
7
27
52

Thank you. However, it collects spaces, but it doesn't' contain information about number of spaces between the words. – Haradzieniec Sep 05 '13 at 15:02
This answer is provably incorrect. https://3v4l.org/Tq66W – mickmackusa Jul 14 '21 at 07:42

score 0 · Answer 5 · answered Sep 05 '13 at 15:07

Here are the results of performance tests:

$str = "This is a    string";

var_dump(time());

for ($i=1;$i<100000;$i++){
//Alma Do Mundo  - the winner
$rgData = preg_split('/\s+/', $str);


preg_match_all('/\s+/', $str, $rgMatches);
$rgResult = array_map('strlen', $rgMatches[0]);// [1,1,4]


}
print_r($rgData); print_r( $rgResult);
var_dump(time());




for ($i=1;$i<100000;$i++){
//nickb
$temp = preg_split('/(\s+)/', $str, -1,PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
$spaces = array();
$words = array_reduce( $temp, function( &$result, $item) use ( &$spaces) {
    if( strlen( trim( $item)) === 0) {
        $spaces[] = strlen( $item);
    } else {
        $result[] = $item;
    }
    return $result;
}, array());
}


print_r( $words); print_r( $spaces);
var_dump(time());

int(1378392870) Array ( [0] => This [1] => is [2] => a [3] => string ) Array ( [0] => 1 [1] => 1 [2] => 4 ) int(1378392871) Array ( [0] => This [1] => is [2] => a [3] => string ) Array ( [0] => 1 [1] => 1 [2] => 4 ) int(1378392873)

I am very surprised to see that two regex calls are somehow outperforming a single regex call. — mickmackusa, Jul 14 '21 at 07:55

score 0 · Answer 6 · answered Apr 15 '15 at 08:57

0

$financialYear = 2015-2016;

$test = explode('-',$financialYear);
echo $test[0]; // 2015
echo $test[1]; // 2016

answered Apr 15 '15 at 08:57

Raj

57
1
1

2

This doesn't resemble the question! and is YEARS late. – mickmackusa Oct 13 '18 at 14:07

mickmackusa · Answer 7 · 2021-07-14T14:05:53.003

Splitting with regex has been demonstrated well by earlier answers, but I think this is a perfect case for calling ctype_space() to determine which result array should receive the encountered value.

Code: (Demo)

$string = "This is a    string";

$words = [];
$spaces = [];

foreach (preg_split('~( +)~', $string, null, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE) as $s) {
    if (ctype_space($s)) {
        $spaces[] = strlen($s);
    } else {
        $words[] = $s;
    }
}

var_export([
    'words' => $words,
    'spaces' => $spaces
]);

Output:

array (
  'words' => 
  array (
    0 => 'This',
    1 => 'is',
    2 => 'a',
    3 => 'string',
  ),
  'spaces' => 
  array (
    0 => 1,
    1 => 1,
    2 => 4,
  ),
)

If you want to replace the piped constants used by preg_split() you can just use 3 (Demo). This represents PREG_SPLIT_NO_EMPTY which is 1 plus PREG_SPLIT_DELIM_CAPTURE which is 2. Be aware that with this reduction in code width, you also lose code readability.

preg_split('~( +)~', $string, -1, 3)

score 0 · Answer 8 · answered Oct 25 '21 at 07:30

What about this? Does someone care to profile this?

    $str = str_replace(["\t", "\r", "\r", "\0", "\v"], ' ', $str); // \v -> vertical space, see trim()
    $words = explode(' ', $str);
    $words = array_filter($words); // there would be lots elements from lots of spaces so skip them.

php explode: split string into words by using space a delimiter

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