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Confusion between factor levels and factor labels
...seems to be a difference between levels and labels of a factor in R.
Up to now, I always thought that levels were the 'real' name of factor levels, and labels were the names used for output (such as tables and plots). Obviously, this is not the case, as the following example shows:
...
MongoDB: Combine data from multiple collections into one..how?
...collection called users_comments that contains the merged data and you can now use that. These reduced collections all have _id which is the key you were emitting in your map functions and then all of the values are a sub-object inside the value key - the values aren't at the top level of these red...
Hibernate Error: org.hibernate.NonUniqueObjectException: a different object with the same identifier
...e with 10 rows based on a primary key combination (column 1 and column 2). Now, you have removed 5 rows from the table at some point of time. Now, if you try to add the same 10 rows again, while hibernate tries to persist the objects in database, 5 rows which were already removed will be added witho...
JavaScript closures vs. anonymous functions
...ree variable.
That free variable is called an upvalue of the closure F.
Now let's use this to figure out who uses closures and who doesn't (for the sake of explanation I have named the functions):
Case 1: Your Friend's Program
for (var i = 0; i < 10; i++) {
(function f() {
var i2...
Why there can be only one TIMESTAMP column with CURRENT_TIMESTAMP in DEFAULT clause?
...TAMP and ON UPDATE
CURRENT_TIMESTAMP clauses. In addition, these clauses now can be used
with DATETIME column definitions. For more information, see Automatic
Initialization and Updating for TIMESTAMP and DATETIME.
http://dev.mysql.com/doc/relnotes/mysql/5.6/en/news-5-6-5.html
...
Renew Provisioning Profile
...
I don't know what fixed it for me, but yes. I think I upgraded xCode or something. Sorry I can't be more precise...
– Tony Adams
Feb 29 '12 at 4:33
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PHP Regex to get youtube video ID?
...ment. In this case we're interested in the query, which is PHP_URL_QUERY.
Now we have the query, which is v=C4kxS1ksqtw&feature=relate, but we only want the part after v=. For this we turn to parse_str which basically works like GET on a string. It takes a string and creates the variables speci...
How to recover stashed uncommitted changes
...oing them in the wrong branch. You just want to take the changes you have now and "move" them to another branch.
This is the easy case, described above. Run git stash save (or plain git stash, same thing). Check out the other branch and use git stash apply. This gets git to merge in your earlie...
Long-lasting FB access-token for server to pull FB page info
...n to see that it is set to Expires: Never!
That should do it. You should now have a Facebook Page Access Token that doesn't expire, unless:
You change your Facebook account password
You lose admin access for the target page
You delete or de-authorize your Facebook App
Any of these will cause t...
What are the best practices for catching and re-throwing exceptions?
...database!";
die;
}
Logging or partial cleanup
Sometimes you do not know how to properly handle an exception inside a specific context; perhaps you lack information about the "big picture", but you do want to log the failure as close to the point where it happened as possible. In this case, yo...