I have a boolean search string for third party index search service: Germany or (Indian, Tech*)
I want my result to be after processing: Germany[45] or (Indian[45], Tech*[45]). Here 45 is the weight needed by the search service.
After googling around for long I was able to get the result: Germany[45] or (Indian[45], Tech[45]*). Here you can see * has came after [45] which is not required.
The output should be: Germany[45] or (Indian[45], Tech*[45]), look for * before [45].
Code:
preg_replace('/([a-z0-9\*\.])+(\b(?<!or|and|not))/i', '$0'."[45]", $term);
So the simple concept behind it is to apply weight to words, but not to or/and/not etc. boolean search sensitive words. Please help me to fine tune the regexp or give a new regex to get required result.
The problem was that you were only getting matches that include a \b - a word boundary. Since an asterisk is a non-word character, it was eliminating it from the match, so the solution was to allow for either a word boundary or an asterisk (\*|\b):
preg_replace('/([a-z0-9.]+)((\*|\b)(?<!or|and|not))/i', '$0'."[45]", $term);
However, it's simpler to do it with a negative lookahead:
preg_replace('/\b(?!or|and|not)([a-z0-9*.]+)/i', '$0'."[45]", $term);
Note: Within character classes asterisks and periods are not metacharacters, so they don't need to be escaped as you had in your original expression: [a-z0-9\*\.]+.
Using a lookahead works like a charm:
preg_replace('/\b(?!or|and|not)([a-z0-9*.])+/i', '$0'."[45]", $term);
You can try it HERE
Edit: Also no need to escape "*" and "." inside a character class
Note that the only special characters or metacharacters inside a character class are the closing bracket (]), the backslash (), the caret (^) and the hyphen (-). The usual metacharacters are normal characters inside a character class, and do not need to be escaped by a backslash. To search for a star or plus, use [+*]. Your regex will work fine if you escape the regular metacharacters inside a character class, but doing so significantly reduces readability.
Source: http://www.regular-expressions.info/
