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Object in R Factor can be used for sequ …

Object in R
Factor can be used for sequence data.

From sequence characters
seq <- c("A", "C", "C", "T", "G") seq.factor <- factor(seq, levels=c("A", "G", "T", "C") From numbers to sequences > seq.num <- c(1,2,3,1,1,3,2,1,4,1,3,2,1) > seq.num.factor <- factor(seq.num, levels=c(1,2,3,4), labels=c("A","G","T","C") )

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There seems to be a bug in a R package n …

There seems to be a bug in a R package named pgam:periodogram().
The function intensity happened to have two cos. One of them should be sin.
Here is the correct version.

function (w, x)
{
n <- length(x) t <- seq(1:n) sp <- ((sum(x * cos(w * t)))^2 + (sum(x * sin(w * t)))^2)/n return(sp) }

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R vector does not have dimension. It onl …

R vector does not have dimension. It only has length.
On the other hand, matrix has dimension.

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R commands to explore time series data …

R commands to explore time series data

ts(data) # create time series objects
time(ts.data) # returns the time

diff(ts.data, lag=1) # difference at the specified lag
lag.plot(ts.data, 9, do.lines=FALSE) # plot with specified lags

plot(stl(ts.data, “per”)) # decomposition of time series data

spec.pgram(ts.data, spans=c(3,3), log=”no”) # non-parametric spectral analysis
spec.ar(ts.data, spans=c(3,3), log=”no”) # parametric estimation

http://www.stat.pitt.edu/stoffer/tsa2/R_time_series_quick_fix.htm

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R commands examining data and its struct …

R commands examining data and its structures
ls() or objects() # list variables
structure()
str() # summary of data
levels()
dim() # dimension of data
class() # show the class of the variable
head() or tail() # showing parts of data

http://www.statmethods.net/input/contents.html

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R normality tests shapiro.test() his …

R normality tests

shapiro.test()

hist(data, prob=TRUE)
lines(density(data))

qqnorm(data)
qqline(data)

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Multi plots in a page gridExtra package …

Multi plots in a page
gridExtra package makes it easier to put multiple plots generated by ggplot2 in a page equivalent to par(mfrow= ).
Example:
http://code.google.com/p/gridextra/wiki/arrange
came across through a conversation in StackOverflow
http://stackoverflow.com/questions/1249548/side-by-side-plots-with-ggplot2-in-r

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Visualizing Data with R http://had.blip….

Visualizing Data with R
http://had.blip.tv/file/3362248/

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R on Linux; Command line auto completion…

R on Linux; Command line auto completion.
Try this. Ctl-R and type a couple letter of the previous command you want to redo.