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What does “S3 methods” mean in R?
...oglecode.com/svn/trunk/google-r-style.html )*. However, I do not know the exact definition of S3 methods/objects.
6 Answers...
How can I quantify difference between two images?
...both images as arrays (scipy.misc.imread) and calculate an element-wise (pixel-by-pixel) difference. Calculate the norm of the difference.
Option 2: Load both images. Calculate some feature vector for each of them (like a histogram). Calculate distance between feature vectors rather than images.
H...
Is gcc std::unordered_map implementation slow? If so - why?
...ady a report in the mailing list. The discussion seem to be pointing to "fixes" to max_load_factor handling, which led to the difference in performance.
– jxh
Jul 24 '12 at 18:21
...
No ConcurrentList in .Net 4.0?
..., unless you "cheat" and just use some sort of linked list and let the indexing suck).
What I thought might be worthwhile was a thread-safe, limited subset of IList<T>: in particular, one that would allow an Add and provide random read-only access by index (but no Insert, RemoveAt, etc., and ...
Explain the use of a bit vector for determining if all characters are unique
... (flag). Each bit in your code states whether the character with bit's index was found in string or not. You could use bit vector for the same reason instead of int. There are two differences between them:
Size. int has fixed size, usually 4 bytes which means 8*4=32 bits (flags). Bit vector usuall...
What is the difference between LL and LR parsing?
Can anyone give me a simple example of LL parsing versus LR parsing?
5 Answers
5
...
Enable access control on simple HTTP server
...RS header for every response.
With the shebang at the top, make the file executable and put it into your PATH, and you can just run it using simple-cors-http-server.py too.
Python 3 solution
Python 3 uses SimpleHTTPRequestHandler and HTTPServer from the http.server module to run the server:
#!/u...
How to test my servlet using JUnit
...ssert.*;
import static org.mockito.Mockito.*;
import java.io.*;
import javax.servlet.http.*;
import org.apache.commons.io.FileUtils;
import org.junit.Test;
public class TestMyServlet extends Mockito{
@Test
public void testServlet() throws Exception {
HttpServletRequest request = mo...
How do I change Bootstrap 3 column order on mobile layout?
I'm making a responsive layout with a top fixed navbar. Underneath I have two columns, one for a sidebar (3), and one for content (9). Which on desktop looks like this
...
How do I (or can I) SELECT DISTINCT on multiple columns?
... FROM t GROUP BY a,b,c
It's a good idea to get used to the GROUP BY syntax, as it's more powerful.
For your query, I'd do it like this:
UPDATE sales
SET status='ACTIVE'
WHERE id IN
(
SELECT id
FROM sales S
INNER JOIN
(
SELECT saleprice, saledate
FROM sales
...