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How do you delete a column by name in data.table?
...hod 3 (could then assign to df3,
df3[, !"foo"]
though if you were actually wanting to remove column "foo" from df3 (as opposed to just printing a view of df3 minus column "foo") you'd really want to use Method 1 instead.
(Do note that if you use a method relying on grep() or grepl(), you need ...
How to use 'find' to search for files created on a specific date? [closed]
...nted out by Max, you can't, but checking files modified or accessed is not all that hard. I wrote a tutorial about this, as late as today. The essence of which is to use -newerXY and ! -newerXY:
Example: To find all files modified on the 7th of June, 2007:
$ find . -type f -newermt 2007-06-07 ! -...
Script entire database SQL-Server
Is there a way I can get a scripting of all tables, procs, and other objects from a database? I know there's an option to script the database but it only gave me some sort of top level script, certainly not a script to create all tables, procs, udfs, .etc.
...
How to close TCP and UDP ports via windows command line
...t the remote machine, the network card, the network cable, and your OS can all cause the socket to close.
Consider also that Fiddler and Desktop VPN software can insert themselves into the network stack and show you all your traffic or reroute all your traffic.
So all you really need is either fo...
How do I add files and folders into GitHub repos?
...en git add *
Then use git commit -m "<Message>" to commit files
Finally git push -u origin master to push files.
When you make modifications run git status which gives you the list of files modified, add them using git add * for everything or you can specify each file individually, then git...
What's the Hi/Lo algorithm?
...ke up a primary key- a "high" number and a "low" number. A client can basically increment the "high" sequence, knowing that it can then safely generate keys from the entire range of the previous "high" value with the variety of "low" values.
For instance, supposing you have a "high" sequence with a...
Why does one hot encoding improve machine learning performance?
...e. The three possible values of w×x are 0, w and 2×w. Either these three all lead to the same decision (they're all < b or ≥b) or "UK" and "French" lead to the same decision, or "French" and "US" give the same decision. There's no possibility for the model to learn that "UK" and "US" should b...
“unadd” a file to svn before commit
...Ok, I guess you and I understand this phrase differently: without deleting all the documents. Unfortunately, svn revert does also delete the newly added changes in the working copy, by restoring the lastest HEAD version. I removed my downvote, but I still feel the warning is important.
...
ActiveRecord.find(array_of_ids), preserving order
...
The answer is for mysql only
There is a function in mysql called FIELD()
Here is how you could use it in .find():
>> ids = [100, 1, 6]
=> [100, 1, 6]
>> WordDocument.find(ids).collect(&:id)
=> [1, 6, 100]
>> WordDocument.find(ids, :order => "field(id,...
Clearing a string buffer/builder after loop
...only benefit of creating the SB outside is not losing the internal (potentially long) char[] of it. If in the first iterator it grew up enough, the second loop will not need to resize any char[]. But for getting the advantage the "clear method" will have to preserve the size of the internal array. s...