Questions tagged [r]

R is a free, open-source programming language & software environment for statistical computing, bioinformatics, visualization & general computing. Please use minimal reproducible example(s) others can run using copy & paste. Show desired output. Use dput() for data & specify all non-base packages with library(). Don't embed pictures for data or code, use indented code blocks instead. For statistics questions, use https://stats.stackexchange.com.

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2468votes
23answers
388kviews

How to make a great R reproducible example

When discussing performance with colleagues, teaching, sending a bug report or searching for guidance on mailing lists and here on Stack Overflow, a reproducible example is often asked and always ...
1442votes
13answers
1.6mviews

How to join (merge) data frames (inner, outer, left, right)

Given two data frames: df1 = data.frame(CustomerId = c(1:6), Product = c(rep("Toaster", 3), rep("Radio", 3))) df2 = data.frame(CustomerId = c(2, 4, 6), State = c(rep("Alabama", 2), rep("Ohio", 1))) ...
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1435votes
19answers
1.3mviews

Sort (order) data frame rows by multiple columns

I want to sort a data frame by multiple columns. For example, with the data frame below I would like to sort by column 'z' (descending) then by column 'b' (ascending): dd <- data.frame(b = factor(c(...
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1115votes
10answers
425kviews

Grouping functions (tapply, by, aggregate) and the *apply family

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.} ...
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  • 28.9k
994votes
18answers
2.1mviews

Remove rows with all or some NAs (missing values) in data.frame

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 ...
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  • 11.1k
984votes
24answers
1.8mviews

Drop data frame columns by name

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 ...
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  • 36.3k
879votes
26answers
1.8mviews

How do I replace NA values with zeros in an R dataframe?

I have a data frame and some columns have NA values. How do I replace these NA values with zeroes?
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870votes
8answers
306kviews

What are the differences between "=" and "<-" assignment operators in R?

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 = ...
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  • 56.6k
848votes
4answers
149kviews

data.table vs dplyr: can one do something well the other can't or does poorly?

Overview 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: data....
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  • 49.7k
806votes
8answers
1.1mviews

Rotating and spacing axis labels in ggplot2

I have a plot where the x-axis is a factor whose labels are long. While probably not an ideal visualization, for now I'd like to simply rotate these labels to be vertical. I've figured this part out ...
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736votes
7answers
87kviews

How can we make xkcd style graphs?

Apparently, folk have figured out how to make xkcd style graphs in Mathematica and in LaTeX. Can we do it in R? Ggplot2-ers? A geom_xkcd and/or theme_xkcd? I guess in base graphics, par(xkcd=TRUE)? ...
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  • 8,744
668votes
11answers
1.1mviews

How to convert a factor to integer\numeric without loss of information?

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....
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  • 9,381
655votes
16answers
1.7mviews

Plot two graphs in same plot in R

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 ...
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648votes
18answers
839kviews

How should I deal with "package 'xxx' is not available (for R version x.y.z)" warning?

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 ...
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639votes
11answers
367kviews

How can I view the source code for a function?

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> &...
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