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Check existence of directory and create if doesn't exist
...le.path(mainDir, subDir))
dir.create() does not crash if the directory already exists, it just prints out a warning. So if you can live with seeing warnings, there is no problem with just doing this:
dir.create(file.path(mainDir, subDir))
setwd(file.path(mainDir, subDir))
...
Plot two graphs in same plot in R
...() will detect this and in turn use plot.function() to plot your function (read up on multiple dispatch to learn more about this). However, lines.function() is not defined, so lines() doesn't know what to do with a parameter of class function. lines can only deal with your data and time series objec...
data.table vs dplyr: can one do something well the other can't or does poorly?
I'm relatively familiar with data.table , not so much with dplyr . I've read through some dplyr vignettes and examples that have popped up on SO, and so far my conclusions are that:
...
How to create and write to a txt file using VBA
....WriteLine("Enter Text")
Console.WriteLine("")
SaveVar = Console.ReadLine
My.Computer.FileSystem.WriteAllText("N:\A-Level Computing\2017!\PPE\SaveFile\SaveData.txt", "Text: " & SaveVar & ", ", True)
Console.WriteLine("")
Console.WriteLine("File Saved")
Console.W...
Rails: Using greater than/less than with a where statement
...the number extracted into a well named constant this may be the easiest to read and understand at a glance.
Inverted logic
We can use the fact that x > y == !(x <= y) and use the where not chain.
User.where.not(id: -Float::INFINITY..200)
which generates the SQL
SELECT `users`.* FROM `use...
CSS Selector that applies to elements with two classes
...till have to deal with ancient browsers like IE6, be aware that it doesn't read chained class selectors correctly: it'll only read the last class selector (.bar in this case) instead, regardless of what other classes you list.
To illustrate how other browsers and IE6 interpret this, consider this C...
Command line progress bar in Java
...T
Simple console progress bar. Progress bar writing now runs on another thread.
Menlo, Fira Mono, Source Code Pro or SF Mono are recommended for optimal visual effects.
For Consolas or Andale Mono fonts, use ProgressBarStyle.ASCII (see below) because the box-drawing glyphs are not aligned prope...
Adding a Method to an Existing Object Instance
I've read that it is possible to add a method to an existing object (i.e., not in the class definition) in Python.
16 Answ...
Implications of foldr vs. foldl (or foldl')
Firstly, Real World Haskell , which I am reading, says to never use foldl and instead use foldl' . So I trust it.
7 A...
Visual Studio 2013 doesn't discover unit tests
...our solution is in a protected drive that you need administrator access to read/write, sometimes only a portion of the tests come up. Definitely run VS as administrator in that case.
If your solution is 64 bit, make sure that Test > Test Settings > Default Processor Architecture is set to x64....