Regular expressions for Google operators - php

Question

Using PHP, I'm trying to improve the search on my site by supporting Google like operators e.g.
keyword = natural/default
"keyword" or "search phrase" = exact match
keyword* = partial match
For this to work I need to to split the string into two arrays. One for the exact words (but without the double quotes) into $Array1() and put everything else (natural and partial keywords) into Array2().
What regular expressions would achieve this for the following string?
Example string ($string)
today i'm "trying" out a* "google search" "test"
Desired result
$Array1 = array(
[0]=>trying
[1]=>google search
[2]=>testing
);
$Array2 = array(
[0]=>today
[1]=>i'm
[2]=>out
[3]=>a*
);
1) Exact I've tried the following for the exact regexp but it returns two arrays, one with and one without the double quotes. I could just use $result[1] but there could be a trick that I'm missing here.
preg_match_all(
'/"([^"]+)"/iu',
'today i\'m "trying" \'out\' a* "google search" "test"',
$result
);
2) Natural/Partial The following rule returns the correct keywords, but along with several blank values. This regexp rule maybe sloppy or should I just run the array through array_filter()?
preg_split(
'/"([^"]+)"|(\s)/iu',
'today i\'m "trying" \'out\' a* "google search" "test"'
);

Answer 1

You can use strtok to tokenize the string.
See for example this tokenizeQuoted function derived from this tokenizedQuoted function in the comments on the strtok manual page:
// split a string into an array of space-delimited tokens, taking double-quoted and single-quoted strings into account
function tokenizeQuoted($string, $quotationMarks='"\'') {
$tokens = array(array(),array());
for ($nextToken=strtok($string, ' '); $nextToken!==false; $nextToken=strtok(' ')) {
if (strpos($quotationMarks, $nextToken[0]) !== false) {
if (strpos($quotationMarks, $nextToken[strlen($nextToken)-1]) !== false) {
$tokens[0][] = substr($nextToken, 1, -1);
} else {
$tokens[0][] = substr($nextToken, 1) . ' ' . strtok($nextToken[0]);
}
} else {
$tokens[1][] = $nextToken;
}
}
return $tokens;
}
Here’s an example of use:
$string = 'today i\'m "trying" out a* "google search" "test"';
var_dump(tokenizeQuoted($string));
The output:
array(2) {
[0]=>
array(3) {
[0]=>
string(6) "trying"
[1]=>
string(13) "google search"
[2]=>
string(4) "test"
}
[1]=>
array(4) {
[0]=>
string(5) "today"
[1]=>
string(3) "i'm"
[2]=>
string(3) "out"
[3]=>
string(2) "a*"
}
}