One R Function A Day.

[This article was first published on Category: R | Huidong Tian's Blog, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here)
Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.

As a R user with 5 years experience, I still have some basic functions that never used or never thought they could exist. Many times I was suprised with some elegant R functions, such like strwidth, parent.frame, etc. No one can know all R functions (and it’s unnecessary), but it’s very convenient to know some basic functions, especially those in the basic packages: base, utils, stats, etc.

I used to have a learning plan: learn one R function a day. But it was terminated because I always fail to remember it. Today, once again I found a useful function of the basic package base, which impelled me to keep learning R as a daily work. How could one guy who said he has 5 years experience but still doesn’t know some basic functions?!

My plan is simple: everyday I log on my computer, one of the first tasks is reading one topic-help document. To avoid forgetting to do this, I need the help page appears automatically.

So, I need to build a topic list first, and I want to start with the base package. The following is my code:

Topic List
URL <- “”
xml<em>1 <- readLines(URL)
ptn <- ‘<a href=\”.*?.html\”>(.*?.html)</a>’
xml</em>2 <- regmatches(xml<em>1, regexec(ptn, xml</em>1))</p>

<p>html.list <- NULL
for (i in 1:length(xml<em>2)) {
  if (length(xml</em>2[[i]]) == 2) {
    html.list <- rbind(html.list, xml_2[[i]][2])
html.list <- sort(unique(html.list[-which(html.list == “00Index.html”)]))

Then I need to choose an order to load the topic one by one. The function parent.frame(2)$ofile is used to get current script’s absolute path.

One by One
i = 0
browseURL(paste(URL, html.list[i + 1], sep = “”))
x <- paste(“i”, i+1, sep = “ <- “)
cur_code <- readLines(parent.frame(2)$ofile)
cur_code[grep(“^i “, cur_code)] <- x
writeLines(cur_code, parent.frame(2)$ofile)

The last step is creating a .bat file to run the R code in a batch mode, and add that file to your Task Scheduler and set the trigger as “at log on”. The content of the .bat file looks like this:

Batch Mode
 R CMD BATCH C:\Packages\base_help.R

Any kind of criticism or commet are welcome!

To leave a comment for the author, please follow the link and comment on their blog: Category: R | Huidong Tian's Blog. offers daily e-mail updates about R news and tutorials about learning R and many other topics. Click here if you're looking to post or find an R/data-science job.
Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.

Never miss an update!
Subscribe to R-bloggers to receive
e-mails with the latest R posts.
(You will not see this message again.)

Click here to close (This popup will not appear again)