Displaying 20 results from an estimated 4000 matches similar to: "manipulating arrays"
2007 Oct 04
5
combining vectors on unequal length
If I have two vectors
X<-1:10
Y<-1:5
When I combine them using cbind, the shorter one is repeated and both are made of the same length. Is there a methods that does this without duplicating the shorter one. I want to use this to store the data back to a file.
Thanks ../Murli
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2007 Aug 07
5
small sample techniques
If my sample size is small is there a particular switch option that I need to use with t.test so that it calculates the t ratio correctly?
Here is a dummy example?
รก =0.05
Mean pain reduction for A =27; B =31 and SD are SDA=9 SDB=12
drgA.p<-rnorm(5,27,9);
drgB.p<-rnorm(5,31,12)
t.test(drgA.p,drgB.p) # what do I need to give as additional parameter here?
I can do it manually but
2009 Jul 14
4
Trig functions strange results
I am trying to calculate coordinate transformations and in the process of debugging my code using debug I found the following
Browse[1]> direction[i]
[1] -1.570796
Browse[1]> cos(direction[i])
[1] 6.123032e-17
Browse[1]> cos(-1.570796)
[1] 3.267949e-07
Browse[1]> direction[i]
[1] -1.570796
Browse[1]> cos(direction[i])
[1] 6.123032e-17
Browse[1]> cos(-1.570796)
[1] 3.267949e-07
2009 Jul 24
2
computing the radius of an arc
Hi!!
I am interesting in computing the radius of an arc that best approximates a curve. Is there an R function that I can use to draw an arc?
Nothing useful came up when I searched help.search. Does anyone have any suggestion to do this?
Thanks ../Murli
2009 May 29
2
strsplit
I am trying split a string and use one part of it to label graphs. I am using strsplit for that. While I am able to split it, how do I access the separated parts.
> filName<-"chrI_2223"
>part<- strsplit(filName,"\\_")
> part
[[1]]
[1] "chrI" "2223"
> part[1]
[[1]]
[1] "chrI" "2223"
I looked up the help archive but did
2007 Jun 26
3
inter-rater agreement index kappa
Is there a function that calculates the inter-rater agreement index
(kappa) in R?
Thanks ../Murli
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2006 Sep 06
2
biplot label size
Which is the parameter that is used to decrease the size of ylabs
plotted in biplot? I tried playing with cex and cex.lab I am not getting
it right
pc <- princomp(USArrests)
biplot(pc, xlabs = rep("", nrow(USArrests)),ylabs=(colnames(USArrests)))
Thanks../Murli
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2007 Mar 18
1
multcomp
I used the multcomp package sometime back for doing multiple
comparisons. I see that it has been updated and the methods like simint
are no longer supported. When I run the program it prompts to me to use
glht. How do I get the lower and upper conf int and the pValues using
glht? Does anyone have an example?
Thanks ../Murli
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2006 Sep 01
3
histograms
I am interested in plotting histograms for the following data
Isoform
Tumor_65_198
Tumor_50_192
Tumor_80_167
Tumor_80_204
Tumor_95_197
Tumor_70_189
Tumor_90_202
Tumor_40_177
Tumor_60_21
Tumor_70_174
Tumor_70_147
Tumor_50_5
ABCC4-2007
1
1
1
6
1
9
10
1
2
0
10
1
ABCC4-2008
5
8
7
5
3
10
5
5
7
3
10
3
ABCC4-2009
0
0
0
0
0
0
0
0
0
0
0
0
ABCC4-2010
2008 Jun 25
1
stringdot
Hi!!
I am trying to figure out how to use the string kernel "stringdot" in kernlab.
k <- function(x,y) {
(sum(x*y) +1)*exp(-0.001*sum((x-y)^2))
}
class(k) <- "kernel"
data(promotergene)
## train svm using custom kernel
gene.k <- ksvm(Class~.,data=promotergene,kernel=k,C=10,cross=5) # works fine in this case
gene.rbf <-
2006 Jul 22
3
Multcomp
Here it is again, hope this is more clear
I am using the following data (only a small subset is given):
Habitat Fungus.yield
Birch 20.83829053
Birch 22.9718181
Birch 22.28216829
Birch 24.23136797
Birch 22.32147961
Birch 20.30783598
Oak 27.24047258
Oak 29.7730014
Oak 30.12608508
Oak 25.76088669
Oak 30.14750974
Hornbeam 17.05307949
Hornbeam 15.32805111
Hornbeam 18.26920177
Hornbeam 21.30987049
2006 Sep 07
1
labeling graphs
I am trying to add text at specific location on my graph. I know this
can be done in R but I can't recollect.
I was trying using locator() to identify the position and use identify()
but I can get it to work. Can someone jog my memory?
Thanks ../Murli
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2007 Mar 13
1
Rcmd and memory
I am running a recursive feature selection wrapper on svm for a large
data set. The routine gets progressively slower. I am deleting the
objects not required. Is there anything else you advise me look for?
I tried running it from the command line but it does not print anything
on the screen. I did not specify any output file and was expecting the
screen to be the default. Can any one help me
2008 Feb 06
1
filling data into objects
I am trying to generate artificial data for feature selection. Basically trying to generate a total of 1000 features with 100 that are informative and rest are uninformative.
Informative.data.class1<-rnorm(100,0.25,1)
Uninformative.data.class1<-rnorm(900,0,1)
Informative.data.class2<-rnorm(100, -0.25,1)
Uninformative.data.class2<-rnorm(900,0,1)
The above will give me one set of data
2008 Jun 04
1
dotchart
I am trying to plot the following data using dotchart
intersect.data<-structure(list(X = structure(c(1L, 3L, 8L, 9L, 10L, 11L, 12L,
13L, 14L, 15L, 2L, 4L, 5L, 6L, 7L), .Label = c("1-100", "1001-1100",
"101-200", "1101-1200", "1201-1300", "1301-1400", "1401-1500",
"201-300", "301-400", "401-500",
2009 Sep 23
1
dotchart to barplots
Hi,
I am trying to plot the following data so that it can be visually represented well. I tried the dotchart but I felt it was too spread out. Then I tried the barplot which is good enough for me. Is there a way to give the labels for the y-axis as in the dot chart? Also, I feel the grey level is confusing, so is there options for designs within the bars? I cannot use color as the journal wants
2009 Jul 15
1
Matrix multiplication precision
Hi!!
I am trying to multiply 5 matrices and then using the inverse of that matrix for further computation. I read about precision problems from the archives and the suggestion was to use as.numeric while computing the products. I am still having problems with the results. Here is how I am using it
#Mn.mat<-(T.mat %*% Rz.mat %*% Q.mat %*% Rz.mat %*% T.mat) # I was doing this in one step
2007 Sep 14
3
x-axis order
Hi all,
I have a time series which contain data collected weekly from week 26
to week 25 the following year. How do I plot this data, so that the
x-axis is displaying the week numbers, ordered as in the data?
Thanks in advance,
Gustaf
---
x<-c(26:52,1:25)
y<-rnorm(52)+1:52
plot(x,y) ## How do I get the x axis to be ordered by the current
ordering of x?
--
Gustaf Rydevik, M.Sci.
tel:
2004 Aug 13
3
Tutorials on R
Hi !!
Is there a good tutorial for the R language ? I really find it hard to
find methods in R.
Thanks and Cheers ../Murli
2007 Aug 01
5
t-distribution
If I have a calculated t can I get the probability associated with it
using an R function by giving it the df and t? I know I can do the whole
calculation using t.test() or get the t-distribution using qt(). If
t=1.11 and df =9 can I get the probability?
Thanks../Murli
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