Displaying 20 results from an estimated 30000 matches similar to: "converting a row of a data.frame to a vector"
2008 Feb 13
2
apply on large arrays
I have a big contingency table, approximately of size 60*2*500*500,
and I need to count the number of cells containing a count of 1 for each
of the factors values defining the first dimension.
Here is my attempt:
tab1<-with(pisa1,table(CNT,GENDER,ISCOF,ISCOM))
tab2<-apply(tab1,1:4,function(x)ifelse(sum(x)==1,1,0))
tab3<-apply(tab2,1,sum)
Computing tab2 is very slow.
Is there a faster
2005 Dec 21
3
NextMethod causes R 2.2.0 to crash (PR#8416)
I found writing the following default method the for the generic
function "julian" causes R to crash.
julian.default <- function(x, ...) {
x <- as.Date(x)
NextMethod("julian", x, ...)
}
Here is a test example
> m <- as.Date("1972-09-27") + 0:10
> m
[1] "1972-09-27" "1972-09-28" "1972-09-29"
2007 May 29
2
looking for the na.omit equivalent for a matrix of characters
I have a matrix of characters (actually numbers that have been read in as
numbers), and I'd like to remove the NA.
I'm familiar with na.omit, but is there an equivalent of na.omit when the NA
are the actual characters "NA"?
Thanks,
Andrew
[[alternative HTML version deleted]]
2008 Feb 01
6
Accessing the elements of a list
Hi R,
I wanted to know how do we access the elements of a list. In particular,
v=list(c(1,2,3,4,5),c(1,2,33,4,5),c(1,2,333,4,5),c(1,2,3333,4,5))
I want to access all the thirds items of the elements of the list. i.e.,
I want to access the elements, 3,33,333,3333. This can be done through
sapply as:
sapply(v,function(x) x[3])
But I need to access this without using
2008 Mar 04
6
vector manipulations
Un texte encapsul? et encod? dans un jeu de caract?res inconnu a ?t? nettoy?...
Nom : non disponible
Url : https://stat.ethz.ch/pipermail/r-help/attachments/20080304/9de37092/attachment.pl
2007 Jul 03
1
termplot - changes in defaults
While termplot is under discussion, here's another proposal. I'd like to
change the default for partial.resid to TRUE, and for smooth to
panel.smooth. I'd be surprised if those changes were to break existing
code.
John Maindonald email: john.maindonald at anu.edu.au
phone : +61 2 (6125)3473 fax : +61 2(6125)5549
Centre for Mathematics & Its Applications, Room
2006 Dec 22
5
substitute creates an object which prints incorrectly (PR#9427)
The function "substitute" seems to fail to make a genuine
substitution, although the printed verision seems fine. Here is an
example.
> m <- substitute(Y <- function(x) FUN(x+1),
+ list(Y = as.name("y"), FUN = as.name("sin")))
> m
y <- function(x) sin(x + 1)
> eval(m)
> y
function(x) FUN(x+1)
However the story doesn't end there. The
2008 Apr 13
4
R equivalent of erfcinv in matlab
I am converting some matlab code into R that use inverse of the
complementary error function, erfcinv and did not find an equivalent in
R, is there such a function in some contributed modules?
Thanks.
2005 Apr 30
3
as.numeric method for objects of class "difftime"
I have just become painfully aware that objects of class "difftime",
generated by the difference of two POSIXct objects, carry a "units"
attribute, which flashes by when the object is printed, for example.
The pain was occasioned when I tried to turn these objects into numberic
objects for use elsewhere as a covariate.
as.numeric(difftime object)
simply turns off the units
2007 Nov 15
3
generate combination set
I have a set data={A,B,C,D,E,F,G}
I want to choose 2 letter from 8 letters, i.e. generate the combination set
for choose 2 letters from 8 letters.
I want to get the liking:
combination set={AB,AC,AD,....}
Does anyone konw how to do in R.
thanks,
Aimin
2008 Mar 09
2
question about matrix one column values matching a vector of values
Hi,
I have a matrix
a = matrix (1:16, 4, 4)
b = c (2,3)
I want to find out which rows of a, where a[,1] equals any values of b?
I know that if b is only one value, e.g, b=2, then what I want is a[a[,1] == 2,]
But what about if it is not one value but a vector of values?
Thanks much in advance.
--
Waverley @ Palo Alto
2007 Jun 01
2
scan a directory and then make a string vector consisting of file names
Dear R-users,
I am looking for a way to scan a directory and then make a string vector
consisting of the file names in the directory.
For example, under c:\temp\
there are 4 files
a.txt, b.txt, c.txt, and d.txt
I would like to have a string vector
c("a.txt","b.txt","c.txt","d.txt")
How do I do that?
Thanks
Taka,
2006 Jan 14
2
initialize expression in 'quasi' (PR#8486)
This is not so much a bug as an infelicity in the code that can easily
be fixed.
The initialize expression in the quasi family function is, (uniformly
for all links and all variance functions):
initialize <- expression({
n <- rep.int(1, nobs)
mustart <- y + 0.1 * (y == 0)
})
This is inappropriate (and often fails) for variance function
"mu(1-mu)".
2007 Jul 02
2
termplot with uniform y-limits
Does anyone have, or has anyone ever considered making, a version of
'termplot' that allows the user to specify that all plots should have
the same y-limits?
This seems a natural thing to ask for, as the plots share a y-scale. If
you don't have the same y-axes you can easily misread the comparative
contributions of the different components.
Notes: the current version of termplot
2007 Jul 02
2
termplot with uniform y-limits
Does anyone have, or has anyone ever considered making, a version of
'termplot' that allows the user to specify that all plots should have
the same y-limits?
This seems a natural thing to ask for, as the plots share a y-scale. If
you don't have the same y-axes you can easily misread the comparative
contributions of the different components.
Notes: the current version of termplot
2008 Apr 07
2
Matching pairs from two data frame
I am looking for a solution to match 2 dataframes from pairs of values (x and
y) as indicated thereafter :
First dataframe :
DATA1
x y a
1 30 40 0.2
2 21 130 0.3
Second dataframe
DATA2
x y b
1 30 40 1
2 40 30 3
3 20 40 7
4 11 30 2
5 130 250 15
6 21 130 17
expected Results :
DATA3
x y a b
1 30 40 0.2 1
2
2008 Mar 07
5
Puzzling coefficients for linear fitting to polynom
Hi,
I can not comprehend the linear fitting results of polynoms. For
example, given the following data (representing y = x^2):
> x <- 1:3
> y <- c(1, 4, 9)
performing a linear fit
> f <- lm(y ~ poly(x, 2))
gives weird coefficients:
> coefficients(f)
(Intercept) poly(x, 2)1 poly(x, 2)2
4.6666667 5.6568542 0.8164966
However the fitted() result makes sense:
>
2007 Nov 08
2
a newbie question about "data"
hi, I am reading Modern Applied Statistics with S 4th ed$B!#(B
page4 have these two lines:
> library(MASS)
> data(chem) # needed in R only
but I find withou the line " data(chem)"
I can still access chem, isn't it?
is it unnecessary or something i missed here?
thanks for the replay in advance.
2006 Nov 10
2
Command Line Prompt Symbol
Hi
I run R in Windows.
Is there a simple way of changing the prompt symbol ">" to, say, "R>" ?
(Not just for a temporary session, but every time R command window is
opened.) The documentation of doing this is rather "sparse".
Much appreciated for your assistance.
Jacob
Jacob L van Wyk
Department of Statistics
University of Johannesburg, APK
P O Box 524
2008 Feb 26
1
The meaning of 'z value' and 'Pr(>|z|)' in the result of glm
Hi all,
I used the function 'glm' to perform logistic regression, and then use 'summary' to display the fitting result. There are 'z value' and 'Pr(>|z|)'
Do they simpily represent the result of 'z test' ? as I perform the 'z test' for a particular variable following the definition, it yields a different result.
Stephen Lau