Displaying 20 results from an estimated 3000 matches similar to: "scoping rules"
2003 Mar 17
2
scoping rules; summary
Hi everyone
thanks for the replies.
The issue was NOT a font problem; I deliberately chose ll1 and l11 as
examples of easily confused variable names (evidently these were too
easily confused ;-). The code snippet was written as intended, and
increment() contained a deliberate, highlighted, bug. I was asking
for guidance on avoiding/finding this sort of coding error.
That was why I wrote
2003 May 02
3
letters to numbers conversion
Hello List
How do I turn
R> simple.example.alphabetic
[,1] [,2] [,3]
[1,] "a" "b" "c"
[2,] "d" "e" "f"
[3,] "g" "h" "i"
into
R> simple.example.numeric
[,1] [,2] [,3]
[1,] 1 2 3
[2,] 4 5 6
[3,] 7 8 9
[ie "a" becomes 1, ..., "z"
2003 Apr 22
3
lexical scope
Hi everyone
another documented feature that was a bit unexpected for me:
R> x <- 19
R> f <- function(t){t+x}
R> f(100)
[1] 119
--as expected: x is visible from within f()
..but...
R> g <- function(a){x <- 1e99 ; return(f(a))}
R> g(4)
[1] 23
--the "x" that is visible from within g() is just 19, which is not the
one I expected it to find.
R> rm(x)
2003 May 29
2
R CMD BATCH --vanilla --slave produces unwanted lines
Hello list
(thanks for all the help on my data.frame() question, especially to
Professor R for a working script...I was pleased to see the solution
wasn't obvious!)
Anyway, now I'm trying to run R in batch mode, but I'm getting extra
output, which I don't want (RedHat 8.3, R-1.7.0):
r:~% cat test.R
options(echo=FALSE)
write(rnorm(4),"")
r:~% R CMD BATCH --vanilla
2003 Jun 23
3
right assignment ("->") and functions
Hi everyone
check this out [R-1.7.0]:
R> f1 <- function(x){x^2}
R> f1 -> f2
R> f2(4)
[1] 16
R>
R> function(x){x^2} -> f3
function(x){x^2} -> f3
R> f3(4)
Error: couldn't find function "f3"
Why does right assignment "->" work in the first but not the second
case? Can anyone else reproduce this?
--
Robin Hankin, Lecturer,
School of
2003 Mar 06
3
multiple plots and postscript()
Kia Ora everybody.
There must be an obvious answer to this, but I can't see it....
I want four square plots in one postscript file. The canonical answer
would be:
postscript(file="~/f.ps",width=5,height=5)
par(pty="s",mfrow=c(2,2))
plot(1:19,xlab="")
plot(1:19,xlab="")
plot(1:19,xlab="")
plot(1:19,xlab="")
dev.off()
But this
2002 Dec 12
2
width and length arguments to postscript()
Hi everyone
This must be a FAQ but I can't find it anywhere...
I want a postscript image of a contour() plot, with axes of equal
length. Try
R> postscript(file="~/f.ps")
R> contour(matrix(rnorm(100),10,10))
R> dev.off()
This isn't what I want: the plotting region is, as documented, quarter
of an inch shy of the paper edge and the axes appear to be different
lengths.
2001 Oct 18
1
tapply problem
Hello everybody.
I have a question that has stumped me and the usual "apply" tricks
don't seem to work. I run a course where each student's performance
is marked by one or more assessors.
I have a data frame containing students' names, assessors' names and
their marks, arranged as follows:
ID student assessor Q1A Q1B Q1C Q2A Q2B Q3
1 2152833
2003 Jun 25
0
frequency table
Robin,
the initial output from apply() is always in the form you have below, but if
it can be 'simplified' into a structure like the matrix, it does so. The
same thing happens with sapply().
If you want to produce a nice matrix as the out put you have to ensure that
the simplification is possible. Here is one way.
> apply(x2, 2, function(x, v) table(factor(x, levels=v)),
2002 Sep 22
3
binom.test()
Hello everybody.
Does anyone else find the last test in the following sequence odd?
Can anyone else reproduce it or is it just me?
> binom.test(100,200,0.13)$p.value
[1] 2.357325e-36
> binom.test(100,200,0.013)$p.value
[1] 6.146546e-131
> binom.test(100,200,0.0013)$p.value
[1] 1.973702e-230
> binom.test(100,200,0.00013)$p.value
[1] 0.9743334
(R 1.5.1, Linux RedHat 7.1)
--
2003 Mar 13
1
apply() and unary operators
Hi everyone.
What's going on here?
> a <- matrix(1:4,2,2)
> a
[,1] [,2]
[1,] 1 3
[2,] 2 4
> apply(a,2,sum)
[1] 3 7
> apply(a,2,"+")
[,1] [,2]
[1,] 1 3
[2,] 2 4
> apply(a,1,"+")
[,1] [,2]
[1,] 1 2
[2,] 3 4
>
help(apply) says that "+" should be quoted but is otherwise silent on
unary
2002 Sep 02
1
reshape()
Dear Helplist
I have a dataframe that holds the Southern Oscillation Index over the
last few years:
R> soi[1:3,]
Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
1 1993 -9 -10 -12 -24 -9 -18 -11 -18 -9 -15 -1 0
2 1994 -2 -1 -14 -26 -13 -12 -18 -20 -19 -16 -9 -15
3 1995 -4 -5 2 -19 -9 -3 4 -1 3 -2 0 -8
QUESTION: how do I coerce reshape() into giving me this:
2002 Nov 26
5
unexpected behaviour of rnorm()
Hello everyone.
If I do
f <- function(n){max(rnorm(n))}
plot(sapply(rep(5000,4000),f)) #[this takes my PC about 30 seconds]
then I get something quite unexpected: gaps in the distribution. For
me, the most noticable one is at about 3.6.
Do others get this? Is it an optical illusion? It can't be right,
can it? Or maybe I just don't understand the good ol' Gaussian very
2003 Feb 13
6
generic handling of NA and NaN and NULL
Hello everybody
I have a generic problem which the following toy function illustrates:
f <- function(n) {
if(abs(n) < pi) {
return(TRUE)
} else {
return(FALSE)
}
}
I want it to return TRUE if abs(n)<pi and FALSE otherwise. f() is
fine as far as it goes, but does not deal well with NA or NaN or NULL
(I want these to signal some problem with the
2002 Sep 25
1
rbind(NULL,NULL) and simplex()
Hello everybody.
I found out the other day something quite astonishing (which I guess
is not astonishing at all to those in the know): in d-dimensional
space, determining whether a given point is inside the convex hull of
a set of n points is elegantly and quickly solvable using linear
programming.
If the columns of matrix "ff" are the coordinates of the set of
points, then in d=2
2003 May 26
1
vectorizing data.frame()
Hello everybody.
I have a dozen or so vectors (of different lengths) which I want to
coalesce into a dataframe, as in the following toy example.
R> foo <- c(1,2,3)
R> bar <- c(7,8)
R> data.frame(name =c(rep("foo",length(foo)),rep("bar",length(bar))),
value=c(foo,bar))
name value
1 foo 1
2 foo 2
3 foo 3
4 bar 7
5 bar
2002 Oct 23
1
vectorizing a function
Dear R-xperts
I have just written a little hypergeometric function, included below
[the hypergeometric function crops up when solving a common type of
ODE].
It works fine on single values of the primary argument z, but
vectorizing it is getting confusing.
The best I have come up with so far just tests for z being longer than
1 and if so, uses sapply() recursively. This is fine, except that it
2002 Jan 14
1
new R documentation on CRAN
Dear R community
A few weeks ago, I uploaded a small text file called R-and-octave.txt
to the contributed docs section of CRAN. This file details
octave/matlab commands and their (near) equivalents in R (Matlab is a
widely-used high-level graphics/mathematics tool and octave a free
clone).
Someone has just pointed out to me that I never announced its
existence to anyone, hence this email (I
2002 Oct 02
2
R vs Fortran
Dear R experts
I work in computational fluid dynamics in 2D: I have a 200-by-200
array of fluid properties such as density and velocity and these
evolve in time (the precise equations depend on the problem).
Up to now, I've been using Fortran and the code is very very messy.
It works, but a professional programmer friend of mine saw the source
code once, and had to be strapped down for his
2002 Mar 26
1
ellipsis question
Hello R experten
I have just written a little function to calculate all pairwise
combinations of two vector arguments:
> pair(c(1,2,3),c(7,8))
[,1] [,2]
[1,] 1 7
[2,] 1 8
[3,] 2 7
[4,] 2 8
[5,] 3 7
[6,] 3 8
>
I want to generalize this to any number of arguments, for example,
<fantasy>
> ntuple(c(1,2,3),c(7,8),c(14,15))
[,1] [,2]