I’d like to unload a package without having to restart R (mostly because restarting R as I try out different, conflicting packages is getting frustrating, but conceivably this could be used in a program to use one function and then another–although namespace referencing is probably a better idea for that use). ?library doesn’t show any … Read more
What is the difference between require() and library()? 8 s 8 In addition to the good advice already given, I would add this: It is probably best to avoid using require() unless you actually will be using the value it returns e.g in some error checking loop such as given by thierry. In most other … Read more
I want to look at the source code for a function to see how it works. I know I can print a function by typing its name at the prompt: > t function (x) UseMethod(“t”) <bytecode: 0x2332948> <environment: namespace:base> In this case, what does UseMethod(“t”) mean? How do I find the source code that’s actually … Read more
I tried to install a package, using install.packages(“foobarbaz”) but received the warning Warning message: package ‘foobarbaz’ is not available (for R version x.y.z) Why doesn’t R think that the package is available? See also these questions referring to specific instances of this problem: My package doesn’t work for R 2.15.2 package ‘Rbbg’ is not available … Read more
I would like to plot y1 and y2 in the same plot. x <- seq(-2, 2, 0.05) y1 <- pnorm(x) y2 <- pnorm(x, 1, 1) plot(x, y1, type = “l”, col = “red”) plot(x, y2, type = “l”, col = “green”) But when I do it like this, they are not plotted in the same … Read more
When I convert a factor to a numeric or integer, I get the underlying level codes, not the values as numbers. f <- factor(sample(runif(5), 20, replace = TRUE)) ## [1] 0.0248644019011408 0.0248644019011408 0.179684827337041 ## [4] 0.0284090070053935 0.363644931698218 0.363644931698218 ## [7] 0.179684827337041 0.249704354675487 0.249704354675487 ## [10] 0.0248644019011408 0.249704354675487 0.0284090070053935 ## [13] 0.179684827337041 0.0248644019011408 0.179684827337041 ## [16] … Read more
What are the differences between the assignment operators = and <- in R? I know that operators are slightly different, as this example shows x <- y <- 5 x = y = 5 x = y <- 5 x <- y = 5 # Error in (x <- y) = 5 : could not … Read more
I have a number of columns that I would like to remove from a data frame. I know that we can delete them individually using something like: df$x <- NULL But I was hoping to do this with fewer commands. Also, I know that I could drop columns using integer indexing like this: df <- … Read more
I’d like to remove the lines in this data frame that: a) contain NAs across all columns. Below is my example data frame. gene hsap mmul mmus rnor cfam 1 ENSG00000208234 0 NA NA NA NA 2 ENSG00000199674 0 2 2 2 2 3 ENSG00000221622 0 NA NA NA NA 4 ENSG00000207604 0 NA NA … Read more
Whenever I want to do something “map”py in R, I usually try to use a function in the apply family. However, I’ve never quite understood the differences between them — how {sapply, lapply, etc.} apply the function to the input/grouped input, what the output will look like, or even what the input can be — … Read more
