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How to drop columns by name in a data frame
...her indexing or the subset function. For example :
R> df <- data.frame(x=1:5, y=2:6, z=3:7, u=4:8)
R> df
x y z u
1 1 2 3 4
2 2 3 4 5
3 3 4 5 6
4 4 5 6 7
5 5 6 7 8
Then you can use the which function and the - operator in column indexation :
R> df[ , -which(names(df) %in% c("z","u")...
Why does CSS work with fake elements?
...y class, I was playing around and found out that CSS works with made-up elements.
19 Answers
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Core pool size vs maximum pool size in ThreadPoolExecutor
...re pool size is
5, max pool size is 10 and the queue is 100.
As requests come in,
threads will be created up to 5 and then tasks will be added to the
queue until it reaches 100. When the queue is full new threads will be
created up to maxPoolSize. Once all the threads are in use and the
queue is ful...
RESTful Login Failure: Return 401 or Custom Response
...hat you looked on is behaving. But a good way of solving this is to have something like an Account object, that you try to GET. If you credentials are correct, you will get the Account object, if you don't want to waste bandwidth just to to a "check" you can do a HEAD on the same resource.
An Accou...
Linq to SQL how to do “where [column] in (list of values)”
...aving to be case-insensitive. As for whether or not it would be, I can't remember whether LINQ to SQL enforces case-sensitivity by default or lets the db settings govern it.
– Jon Skeet
May 31 '17 at 20:36
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How to create SBT project with IntelliJ Idea?
...te sbt project. Basic features work out of the box using both solutions, some complex builds can have problems, so try other tools to see if it works there.
IntelliJ
IntelliJ IDEA has become so much better these days. The current version (14.0.2) supports sbt projects out of the box with the Scala...
How should I edit an Entity Framework connection string?
...o edit my app.config file to change the connection string for an Entity Framework data model ( .edmx file). But I'd like to know: Is there a way to edit the EF connection string using the designer?
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How do I rename all files to lowercase?
I have for example TREE.wav, ONE.WAV. I want to rename it to tree.wav, one.wav. How do I rename all files to lowercase?
4 ...
Clean ways to write multiple 'for' loops
For an array with multiple dimensions, we usually need to write a for loop for each of its dimensions. For example:
16 An...
Discard all and get clean copy of latest revision?
I'm moving a build process to use mercurial and want to get the working directory back to the state of the tip revision. Earlier runs of the build process will have modified some files and added some files that I don't want to commit, so I have local changes and files that aren't added to the reposi...