10 R One Liners to Impress Your Friends

June 5, 2011

(This article was first published on DataDebrief, and kindly contributed to R-bloggers)

Following the trend of one liners for various languages (Haskell, Scala, Python), here’s some examples in R

Multiply Each Item in a List by 2

# otherwise

Sum a List of Numbers


# otherwise
sum(unlist(list(1:4))) # or simply

Verify if Exists in a String

wordlist = c("lambda", "data", "plot", "statistics", "R")
tweet = c("R is an integrated suite of software facilities for data manipulation, calculation and graphical display")
wordlist[wordlist %in% (c(unlist(strsplit(tweet,' ', fixed=T))))]

Read in a File

readLines("data.file", n=-1)

Happy Birthday to You!

lapply((1:4),function(x){ paste(c("Happy Birthday to ", ifelse(x!=3, "you", "dear Name")), sep="", collapse="")})

Filter list of numbers

n = c(49, 58, 76, 82, 88, 90); c(list(n[which(n<=60)]),list(n[which(n>60)]))

Fetch and Parse an XML web service

library('XML'); xmlParseDoc('http://search.twitter.com/search.atom?&q=R-Project', asText=F)

Find minimum (or maximum) in a List

# for lists
lapply(list(c(14, 35, -7, 46, 98)), min, classes="numeric", how="replace")

# otherwise
min(unlist(list(14, 35, -7, 46, 98)))
# or simply
min(c(14, 35, -7, 46, 98))
max(c(14, 35, -7, 46, 98))

Parallel Processing

# http://cran.r-project.org/web/packages/doSMP/vignettes/gettingstartedSMP.pdf
# copy from Section 4 An example doSMP session
library(doSMP); w <- startWorkers(workerCount = 4); registerDoSMP(w); foreach(i = 1:3) %dopar% sqrt(i)

Sieve of Eratosthenes

##ok, this one is a little cheating
library('spuRs'); primesieve(c(),2:50)

To leave a comment for the author, please follow the link and comment on their blog: DataDebrief.

R-bloggers.com offers daily e-mail updates about R news and tutorials on topics such as: visualization (ggplot2, Boxplots, maps, animation), programming (RStudio, Sweave, LaTeX, SQL, Eclipse, git, hadoop, Web Scraping) statistics (regression, PCA, time series, trading) and more...

If you got this far, why not subscribe for updates from the site? Choose your flavor: e-mail, twitter, RSS, or facebook...

Comments are closed.