Posted by Paul Groves on 09/08/05 17:48

Brent Baisley wrote:
> It sounds like you are trying to build a full text search string,
> perhaps for searching a MySQL database?

Actually, I was thinking of doing a MySQL non full-text search, hence
the need to split the words/phrases up so that they could then be fed
into individual "WHERE fieldname LIKE "%word%" SQL fragments, but now
I'm thinking maybe it would be a better idea to do a FULLTEXT search
(with the indexes set up), espc. as what I need it for is a
"Google-like" search of many fields at once within a table, would
certainly make for a less complex query...

> Below is the function I came up
> with a while ago. It's worked fine, although it currently does not
> check for multiple spaces, but that should be easy to change.

Yup, I've written an enhanced_explode() function that does just this
(using preg_split)

> It uses a
> space as a delimiter and it checks for quotes for searching on phrases.

I like the way this bit works! :-)

> It returns the search string for a MySQL full text boolean mode search.
> You should be able to easily adapt it to your specific needs.

There's a few things I'm a bit confused about - e.g. if you're doing a
FULLTEXT search, why do you need to split things up at all? In FULLTEXT
searches the search string is parsed into words anyway. However, I can
see that you've seperated all the search values with a "+" by the end,
and that you've appended a "*" onto the end of search terms, so I assume
what you're actually doing is preparing for a BOOLEAN mode FULLTEXT
search? Actually, this must be the case, otherwise the phrase search is
meaningless! :-)

A boolean search could actually be quite useful for my needs, my only
concerns really are a) Results are not sorted by relevance unlike a
normal FULLTEXT search (so what are they ordered by?) and b) if I use
the function below, then any user-added operators ("+", "-" etc.) in
$seachVal are not really dealt with properly - am I right in assuming
either use the function, or allow users to enter their own operators,
but not both (apart from quoting phrases)?

BTW sorry for my ignorance here, I''ve only recently begun to look into
FULLTEXT searches!

thanks

Paul

> function prepFullTextSearch($searchVal) {
> //Split words into list
> $word_List = explode(' ',stripslashes(trim
> ($searchVal)));
> //Step through word list to get search phrases
> $i = 0;
> $isPhrase = false;
> foreach($word_List as $word) {
> $searchItems[$i] = trim(($isPhrase?$searchItems[$i].'
> '.$word:$word));
> //Check for start of Phrase
> if(substr($searchItems[$i],0,1) == '"') {
> $isPhrase = true;
> }
> //If not building a phrase, append wildcard (*) to end of word
> if(!$isPhrase) {
> $searchItems[$i] .= '*';
> $i++;
> }
> //Check for end of Phrase
> if(substr($searchItems[$i],-1) == '"') {
> $isPhrase = false;
> $i++;
> }
> }
> $searchVal = '+'.implode(' +',$searchItems);
> return $searchVal;
> }
>
>
>
> On Sep 7, 2005, at 10:54 AM, Paul Groves wrote:
>
>> I want to be able to break up a number of search terms typed into an
>> input
>> box into array, simple enough one would think, just use explode, e.g
>>
>>
>> $array = explode(" ", $string);
>>
>>
>> But what if I want to be able to cope with search terms seperated by > 1
>> space (a common typing error)? This should work:
>>
>>
>> function enhanced_explode($string) {
>> $array = preg_split ("/\s+/", $string);
>> return ($array);
>> }
>>
>>
>> But what if I want to allow "Google"-type search parameters, so that
>> something like the following is split into 3 search terms?:
>> firstsearchterm "second search term" thirdsearchterm
>> The following code will do the trick, but is slow and doesn't allow for
>> multiple spaces as the delimiter, nor the possibility of multiple
>> delimiters
>> (e.g. " ", "+", "," etc.)
>>
>>
>> function explode2($delimeter, $string)
>> {
>> for ($i = 0; $i < strlen($string); $i++)
>> {
>> if ($string{$i} == '"')
>> {
>> if ($insidequotes)
>> $insidequotes = false;
>> else
>> $insidequotes = true;
>> }
>> elseif ($string{$i} == $delimeter)
>> {
>> if ($insidequotes)
>> {
>> $currentelement .= $string{$i};
>> }
>> else
>> {
>> $returnarray[$elementcount++] = $currentelement;
>> $currentelement = '';
>> }
>> }
>> else
>> {
>> $currentelement .= $string{$i};
>> }
>> }
>>
>> $returnarray[$elementcount++] = $currentelement;
>>
>> return $returnarray;
>> }
>>
>> None of these solutions are ideal, I guess a clever regular exression
>> (preg_split) could solve this, but I'm not quite sure how - does
>> anyone have
>> any ideas? Thanks
>>
>> Paul
>>
>> --
>> PHP General Mailing List (http://www.php.net/)
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>>
>>
>>
>


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Paul Groves paul.groves@oucs.ox.ac.uk
Senior Project Officer, Academic Computing Development Team
www.oucs.ox.ac.uk/acdt/
ACDT is part of the Learning Technologies Group
www.oucs.ox.ac.uk/ltg/

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