Using preg_split on an empty string

Question

In PHP, when I run the following command:

$text = "";
$arr = preg_split('/,/', $text, PREG_SPLIT_NO_EMPTY);
print_r($arr);

I get the following array with a single empty element:

Array
(
    [0] => 
)

Yet, if I run it with -1 as the limit:

$text = "";
$arr = preg_split('/,/', $text, -1, PREG_SPLIT_NO_EMPTY);
print_r($arr);

I get a completely empty array:

Array
(
)

Why is this the case? According to the PHP manual -1 is the default value so I would expect the results to be the same in both cases.

Have you tried to count the characters with strlen() function? — node_modules
– node_modules, Commented Apr 18, 2016 at 6:23
PREG_SPLIT_NO_EMPTY If this flag is set, only non-empty pieces will be returned by preg_split(). so its giving onli non emty value so use another like "PREG_SPLIT_DELIM_CAPTURE" — Brijal Savaliya
– Brijal Savaliya, Commented Apr 18, 2016 at 6:26

Rizier123 · Accepted Answer · 2016-04-18 06:33:09Z

5

preg_split($pattern , $subject [, int $limit = -1     [, int $flags = 0 ]] )
preg_split('/,/'    , $text     , PREG_SPLIT_NO_EMPTY                      );

The third parameter is the limit, PREG_SPLIT_NO_EMPTY == 1, when you pass PREG_SPLIT_NO_EMPTY as the third argument you're telling it the limit is 1 - you're not passing it in as a flag.

edited Apr 18, 2016 at 6:33

Rizier123

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answered Apr 18, 2016 at 6:26

user3942918

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1 Comment

Rizier123 Over a year ago

So in short: Passed the constant as wrong argument = Empty elements are allowed

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