Displaying 20 results from an estimated 2000 matches similar to: "R Books listing on R-Project"
2008 Nov 24
14
how to test for the empty set
Dear R-help,
I first thought that the empty set (for a vector) would be NULL.
x <- c()
x
However, the documentation seems to make clear that there _many_ empty
sets depending on the vector's mode, namely, numeric(0), character(0),
logical(0), etc. This is borne out by
y <- letters[1:3]
z <- letters[4:6]
intersect(y,z)
which, of course, is non-NULL:
is.null(character(0)) #
2009 May 30
3
setdiff bizarre (was: odd behavior out of setdiff)
Dear R-devel,
Please see the recent thread on R-help, "Odd Behavior Out of
setdiff(...) - addition of duplicate entries is not identified" posted
by Jason Rupert. I gave an answer, then read David Winsemius' answer,
and then did some follow-up investigation.
I would like to change my answer.
My current version of setdiff() is acting in a way that I do not
understand, and a way
2009 May 30
3
setdiff bizarre (was: odd behavior out of setdiff)
Dear R-devel,
Please see the recent thread on R-help, "Odd Behavior Out of
setdiff(...) - addition of duplicate entries is not identified" posted
by Jason Rupert. I gave an answer, then read David Winsemius' answer,
and then did some follow-up investigation.
I would like to change my answer.
My current version of setdiff() is acting in a way that I do not
understand, and a way
2008 Nov 29
2
Using grep() to subset lines of text
I have two vectors, a and b. b is a text file. I want to find in b those
elements of a which occur at the beginning of the line in b. I have the
following code, but it only returns a value for the first value in a, but I
want both. Any ideas please.
a = c(2,3)
b = NULL
b[1] = "aaa 2 aaa"
b[2] = "2 aaa"
b[3] = "3 aaa"
b[4] = "aaa 3 aaa"
2009 May 29
2
Odd Behavior Out of setdiff(...) - addition of duplicate entries is not identified
I think I am using the improved version of setdiff(...) that handles data.frames, so I think some odd behavior was expected but this one is escaping me.
It appears that the the addition of duplicate entries is not caught by the setdiff(...). Is this expected behavior?
If so, is there another method or approach that should be used to identify duplicate row entries between two different data
2007 Dec 10
1
setdiff for data frames
Hello,
I have been interested in setdiff() for data frames that operates
row-wise. I looked in the documentation, mailing lists, etc., and
didn't find exactly the right thing. Given data frames A, B with the
same columns, the goal is to extract the rows that are in A, but not
in B. Of course, one can usually do setdiff(rownames(A), rownames(B))
but that is cheating. :-)
I played around a
2009 May 14
2
can you tell what .Random.seed *was*?
Dear R-help,
Suppose I write a script that looks something like this:
#### script.R
set.seed(something)
x <- rnorm(100)
y <- runif(500)
# bunch of other stuff
save.image()
### end of script.R
Now, I give you a copy of my script.R (with the set.seed statement
removed, of course) together with the .RData file that was generated
by the save.image() command.
Question:
1) can you tell
2009 Feb 17
2
cumsum vs. sum
I recently traced a bug of mine to the fact that cumsum(s)[length(s)]
is not always exactly equal to sum(s).
For example,
x<-1/(12:14)
sum(x) - cumsum(x)[3] => 2.8e-17
Floating-point addition is of course not exact, and in particular is
not associative, so there are various possible reasons for this.
Perhaps sum uses clever summing tricks to get more accurate results?
In some
2009 Jul 29
3
Object equality for S4 objects
To test two environments for object equality (Lisp EQ), I can use 'identity':
> e1 <- environment(local(function()x))
> e2 <- environment(local(function()x))
> identical(e1,e2) # compares object identity
[1] FALSE
> identical(as.list(e1),as.list(e2)) # compares values as name->value mapping
[1] TRUE # (is there a
2009 Mar 09
3
E`<`<rrors in recursive default argument references
Tested in: R version 2.8.1 (2008-12-22) / Windows
Recursive default argument references normally give nice clear errors.
In the first set of examples, you get the error:
Error in ... :
promise already under evaluation: recursive default argument
reference or earlier problems?
(function(a = a) a ) ()
(function(a = a) c(a) ) ()
(function(a = a) a[1] ) ()
(function(a = a)
2009 May 20
2
Class for time of day?
What is the recommended class for time of day (independent of calendar
date)?
And what is the recommended way to get the time of day from a POSIXct
object? (Not a string representation, but a computable representation.)
I have looked in the man page for DateTimeClasses, in the Time Series
Analysis Task View and in Spector's Data Manipulation book but haven't found
these. Clearly I can
2009 Jan 04
1
Bivarite Weibull Distribution
HI
Every one
Could some one provide me definitions of following bivariate distributions
gamma, exponencial, Weibull, half-normal , Rayleigh, Erlang,chi-square
thanks
A.S. Qureshi
2008 Jun 04
1
permsn incorrect when x==m (library: prob) (PR#11571)
Full_Name: Obnoxious
Version: 2.7.0
OS: Windows
Submission from: (NULL) (121.223.77.238)
Objective:
Generate all permutations of the elements of x taken m at a time.
Library:
prob
Function:
permsn
Issue:
Does not appear to be working correctly when x==m.
Example:
libary(prob)
permsn(2,1) i.e., x > m
#Gives the correct result of
[,1] [,2]
[1,] 1 2
#Yet
permsn(2,2) i.e., x==m
2007 Sep 16
2
power calculation for repeated measures ANOVA?
Is there a way to calculate power for repeated
measures ANOVA (2 groups x 7 observations)? I have
searched all over, but all I can find is
power.anova.test, but that would not give accurate
results, right?
Thanks,
Matt Bridgman
2007 Dec 21
2
number of count of each unique row
Hi,
I have a matrix of duplicate rows. How to output a list the unique rows with their count? I have used "unique" to have the unique rows, but can't produce the occurences of each unique row.
Thanks
Louis
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2009 Jul 30
1
Logistic regression and R
Hello everybody :-)
I have some data that I want to model with a logistic regression, most
of the independent variables are numeric and the only dependent is
categorical, I was thinking that I could apply a logistic regression
using glm but I wanted to deepen my knowledge of this so I tried to do
some reading and found the "iris" dataset, now I would like to ask two
things, first
2009 Dec 15
1
Starting with R and distributions graphics
HI, i'm really new of R and i need some help.
I have to describe some distributions for some dices throw:
- launching 3 dices i need the distribution of the sum of the two higher
values
- launching 4 dices i need the distribution of the occurrences of the same
value
possibly i need a way to compare the two distribution adding the fourth dice
to the first without summing it (only for
2010 Mar 19
1
Gamma parametrization
Dear R users,
?rgamma gives me :
rgamma(n, shape, rate = 1, scale = 1/rate)
rate: an alternative way to specify the scale.
The Gamma distribution with parameters ‘shape’ = a and
‘scale’ = s has density
f(x)= 1/(s^a Gamma(a)) x^(a-1) e^-(x/s)
Should I understand that scale=1/rate ? Is it written somewhere ?
Then
2010 Sep 08
2
choose.dir() gone?
Hi,
I fail to find "choose.dir()" in my current R install (see below)? Didn't
that exist at some point? How to achieve "file.choose()" equivalent
functionality for directories?
Thanks for any hints, Joh
> sessionInfo()
R version 2.11.1 (2010-05-31)
x86_64-pc-linux-gnu
locale:
[1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C
[3]
2013 Sep 11
2
create_local_nt_token_from_info3 not pulling supplementary UNIX groups
I'm trying to solve this issue I'm having where using 'valid users =
+unixgroup' just plain doesn't work. I can't find any /documented/
reason why this is so, but nevertheless, it seems to be the case. This
is with samba 3.6.18, but seems to exist in all of 3.6.x and most or all
of 3.5.x and perhaps earlier as well (see bug #6681).
From what I can tell, the underlying