ranking

Following on from this answer I want to know what the best way to use PostgreSQL's built-in full text search is if I want to sort by rank, and limit to only matching queries. Let's assume a very simple table. CREATE TABLE pictures ( id SERIAL PRIMARY KEY, title varchar(300), ... ) or whatever. Now I want to search the title field. First I create an index: CREATE INDEX pictures_title ON pictures USING gin(to_tsvector('english', title)); Now I want to search for 'small dog' . This works: SELECT pictures.id, ts_rank_cd( to_tsvector('english', pictures.title), 'small dog' ) AS score FROM pictures

I need an algorithm that allows me to determine an appropriate <priority> field for my website's sitemap based on the page's views and comments count. For those of you unfamiliar with sitemaps, the priority field is used to signal the importance of a page relative to the others on the same website. It must be a decimal number between 0 and 1. The algorithm will accept two parameters, viewCount and commentCount , and will return the priority value. For example: GetPriority(100000, 100000); // Damn, a lot of views/comments! The returned value will be very close to 1, for example 0.995

I've been looking at ranking algorithms recently, specifically those used by Reddit and Hacker News. The algorithms themselves are simple enough, but I don't quite understand how they are used. One thing that I could do is implement the algorithm straight in SQL, so that every time a user goes to a page displaying ranked posts, something like this would run: SELECT thing1, thing2 FROM table ORDER BY ranking_algorithm DESC LIMIT page*20, 20 There are several similar questions on SO, but the only answer given is to put the ranking algorithm inside the SQL query. Then the thread dies... Putting

Trying to fetch top n bottom n rows. Though it gives me result but, it takes lot of time. I believe it scans table twice. Code used: WITH TI AS (SELECT * FROM (SELECT Column1, Column2, Colmn3 FROM TABLE ORDER BY DESC ) WHERE ROWNUM<=5), T2 AS (SELECT * FROM (SELECT Column1, Column2, Colmn3 FROM TABLE ORDER BY ASC ) WHERE ROWNUM<=5) SELECT * FROM T1 UNION ALL SELECT * FROM T2 How can i fetch this in more faster way?? Considering that tables are updated regularly. The best way to solve this problem depends in part on your Oracle version. Here is a very simple (and, I suspect, very efficient)

I was trying to find the Rank of the given string in the list of permutations and was hoping someone can find the bug. function permute() { var W = $('input').val(), C = []; for (var i = 0; i < 26; i++) C[i] = 0; var rank = 1; for (var i = 0; i < W.length; i++) { C[W.charCodeAt(i) - 'a'.charCodeAt(0)]++; } var repeated= 1; for (var i = 0; i < C.length; i++) { if(C[i] > 0) { repeated *= fact(C[i]); } } if (W !== '') { for (var i = 0; i < W.length; i++) { //How many characters which are not used, that come before current character var count = 0; for (var j = 0; j < 26; j++) { if (j == (W

I would like to rank the values in a dictionary. For instance, I have this dictionary: {"A": 10, "B: 3, "C": 8, "D": 3, "E": 2} The result should look like: {"E": 1, "B": 2, "D": 2, "C": 4, "A": 5} Please note that D is ranked as fourth because B and D are tied at position two . Hence, there is no position three . Similar solutions have already been given in other threads, however they did not take into account ex-aequo positions in the traditional way: Adding a rank to a dict in python and Python Ranking Dictionary Return Rank First sort the data in ascending order based on the number, like