Blog Archives

50000 Revisions Committed to R

October 10, 2009
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50000 Revisions Committed to R

oday Romain Francois posted an interesting topic in the R-help list, and you can read his blog post for more details: celebrating R commit #50000. 50000 is certainly not a small number; we do owe R core members a big “thank you” for their great efforts in this fantastic statistical language in the 13 years.

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How to Import MS Excel Data into R

September 26, 2009
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How to Import MS Excel Data into R

s Sir Francis Bacon said, “Histories make men wise; poets witty; the mathematics subtile; natural philosophy deep; moral grave; logic and rhetoric able to contend.” And Windows stupid. He should have added the last sentence if he were a Windows user in this age. 1. Avoid Using M$ Excel A lot of R users often ask this question:

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Formatting Decimals in Texts with R

August 30, 2009
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Formatting Decimals in Texts with R

anping Chen raised a question in the Chinese COS forum on the output of Eviews: how to (re)format the decimal coefficients in equations as text output? For example, we want to round the numbers in CC = 16.5547557654 + 0.0173022117998*PP + 0.216234040485 * PP(-1) + 0.810182697599 * (WP + WG) to the 3rd decimal places.

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Counterintuitive Results in Flipping Coins

August 28, 2009
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Counterintuitive Results in Flipping Coins

oin-flipping is a rather old topic in probability theory, so most of us think we know very well about it, however, the other day I saw a question about this old topic (in David Smith’s REvolution?) which was beyond me expectation: how many times do we need to flip the coin until we get a

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Simulation of Burning Fire in R

June 11, 2009
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Simulation of Burning Fire in R

inlin Yan posted a cool (hot?) simulation of burning fire with R in the COS forum yesterday, which was indeed a warm welcome. I’m not sure whether our forum members will be scared by the “fire” under the title “Welcome to COS Forum”. The fire was mainly created by the function image() with

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Creating Tag Cloud Using R and Flash / JavaScript (SWFObject)

June 10, 2009
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Creating Tag Cloud Using R and Flash / JavaScript (SWFObject)

ag cloud is a bunch of words drawn in a graph with their sizes proportional to their frequency; it’s widely used in blogs to visualize tags. We can observe important words quickly from a tag cloud, as they often appear in large fontsize. Tony N. Brown asked how to “graphically represent frequency of words in

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Enhanced tidy.source() (Preserve Some Comments)

March 31, 2009
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After a few hours’ work, I modified the function tidy.source() in the animation package so that it can preserve complete comment lines. See the tidy.source() wiki page for example. tidy.source <- function(source = "clipboard", keep.comment = TRUE, keep.blank.line = FALSE, begin.comment, end.comment, ...) { # parse and deparse the code tidy.block = function(block.text)

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Identify Data Points in Off-Screen R Graphics Devices

March 16, 2009
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Today Ruya Gokhan Kocer asked me how to use the R function identify() in off-screen graphics devices. Actually it’s pretty easy as long as we obtain the list returned by identify(pos = TRUE). For example, # open a windows device x11() x = rnorm(20) y = rnorm(20) plot(x, y) # identify 5 points id = identify(x, y, n = 5, pos =

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