Displaying 20 results from an estimated 20000 matches similar to: "substitute, expression and factors"
2009 Sep 02
2
combining grid.text, expression and variables
Dear R-users,
I am trying to use the grid.text and expression functions to display
several character strings and plotmath text on a viewport. Some strings
can include a variable portion (PI.limits in the following example),
which I thought could be implemented by combining the bquote and the
expression functions. Unfortunately, my expressions do not seem to be
evaluated. I would greatly
2009 Oct 01
1
inverse currying
Dear list,
I have the following function,
sugar = function(fun, id = "id"){
ff <- formals(fun)
if( id %in% names(ff))
stop("id is part of args(fun)")
formals(fun) <- c(unlist(ff), alist(id=))
fun
}
which one may use on a function foo,
foo = function(x){
x
}
sugar(foo) # results in the extended closure,
function (x, id)
{
x
}
Its limitation (other
2009 Nov 03
2
how to display a string containing greek chrs and variables
I'm trying something that I thought would be pretty simple, but it's
proving quite frustrating...
I want to display, for instance, the correlation coefficient "rho" in a graph.
I can do something like:
text(x, y, paste("rho =", cor))
where cor would be my previously calculated correlation coefficient,
and x and y the coordinates.
Obviously that displays
2008 Jun 25
1
expression, strsplit, ...
DeaR list,
I'm a bit lost in the behavior of substitute and co.
I often use fairly long axis labels in my graphs (long to write, that
is). Typically, they would contain some greek letters and units with
exponents, as in:
> xlab=expression(paste("text ", alpha, " / ", V,".", m^{-3}, ".",
> kg^{-2}, ".", l^{4}))
To make this a
2007 Jul 19
1
substitute and expression (Peter Dalgaard)
In this connection, note the following
> a4 <- 4
> plotThis <- bquote(alpha==.(a), list(a=a4))
> do.call(plot, list(1:10, main=do.call(expression, c(plotThis))))
> do.call(plot, list(1:10, main=do.call(expression, plotThis)))
Error in do.call(expression, plotThis) : second argument must be a list
> ## Whereas plotThis has class "call", c(plotThis) has class
2010 Feb 14
3
evaluate variable within expression - how?
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2011 Mar 09
2
switch and factors
Dear list,
Reading the help page for ?switch didn't give me more than a hint at
what's going on here,
x = 5
y = 2
foo <- function(a="x"){
switch(a, "x" = x,
"y" = y)
}
foo(factor('x', levels=c('y', 'x')))
# 2
It seems that switch, when given a factor, uses the numeric codes
rather than the string
2009 Nov 10
3
drop unused levels in subset.data.frame
Dear list,
subset has a 'drop' argument that I had often mistaken for the one in
[.factor which removes unused levels.
Clearly it doesn't work that way, as shown below,
d <- data.frame(x = factor(letters[1:15]), y = factor(LETTERS[1:3]))
s <- subset(d, y=="A", drop=TRUE)
str(s)
'data.frame': 5 obs. of 2 variables:
$ x: Factor w/ 15 levels
2009 Mar 25
2
"[.data.frame" and lapply
Dear all,
Trying to extract a few rows for each element of a list of
data.frames, I'm puzzled by the following behaviour,
> d <- lapply(1:4, function(i) data.frame(x=rnorm(5), y=rnorm(5)))
> str(d)
>
> lapply(d, "[", i= c(1)) # fine, this extracts the first columns
> lapply(d, "[", j= c(1, 3)) # doesn't do nothing ?!
>
> library(plyr)
2009 Mar 25
2
"[.data.frame" and lapply
Dear all,
Trying to extract a few rows for each element of a list of
data.frames, I'm puzzled by the following behaviour,
> d <- lapply(1:4, function(i) data.frame(x=rnorm(5), y=rnorm(5)))
> str(d)
>
> lapply(d, "[", i= c(1)) # fine, this extracts the first columns
> lapply(d, "[", j= c(1, 3)) # doesn't do nothing ?!
>
> library(plyr)
2009 Nov 20
1
How to concatenate expressions
Dear R-users,
I am developing a plotting function, which receives expressions and
character/numerical vectors as part of the many input arguments and
which tries to concatenate them before displaying the result to the
plot. I currently cannot find a way to make this concatenation works. I
have read several posts in the list that solved this problem by pasting
the different elements together
2009 Apr 03
3
plyr and table question
Dear all,
I'm puzzled by the following example inspired by a recent question on
R-help,
cc <- textConnection("user_id website time
20 google 0930
21 yahoo 0935
20 facebook 1000
25 facebook 1015
61 google 0940")
d <- read.table(cc, head=T) ; close(cc)
table(d$user_id) # count the
2011 Apr 26
2
grid stringHeight
Dear all,
I'm puzzled by the behavior of stringHeight in the grid package.
Consider the following test,
library(grid)
test <- function(lab="dog", ...){
g1 <- textGrob(lab)
g2 <- rectGrob(height=grobHeight(g1), width=grobWidth(g1))
gg <- gTree(children=gList(g1,g2), ...)
print(c("height:", convertUnit(stringHeight(lab), "mm",
2010 Aug 27
3
How to plot an expression-label with variable text
Disclaimer: I have read plotmath, but maybe it's too late today:
How do I get the two labels to be the same:
plot.new()
lab =expression(paste("Estimated ", t[50]," from tgv"))
text(0.5,0.5,lab)
# Should look the same as above. I could not get the substitute right:
what = "tgv"
lab =expression(paste("Estimated ", t[50]," from ",what))
2010 Sep 09
1
scalable < > delimiters in plotmath
Dear list,
I read in ?plotmath that I can use bgroup to draw scalable delimiters
such as [ ] and ( ). The same technique fails with < > however, and I
cannot find a workaround,
grid.text(expression(bgroup("<",atop(x,y),">")))
Error in bgroup("<", atop(x, y), ">") : invalid group delimiter
Regards,
baptiste
sessionInfo()
R version
2010 Sep 09
1
scalable < > delimiters in plotmath
Dear list,
I read in ?plotmath that I can use bgroup to draw scalable delimiters
such as [ ] and ( ). The same technique fails with < > however, and I
cannot find a workaround,
grid.text(expression(bgroup("<",atop(x,y),">")))
Error in bgroup("<", atop(x, y), ">") : invalid group delimiter
Regards,
baptiste
sessionInfo()
R version
2009 Sep 28
2
dichromat, regexp, and grid objects
Dear list,
The dichromat package defines a dichromat function which "Collapses
red-green color distinctions to approximate the effect of the two
common forms of red-green colour blindness, protanopia and
deuteranopia."
library(dichromat)
library(grid)
colorStrip <-
function (colors = 1:3, draw = TRUE)
{
x <- seq(0, 1 - 1/length(colors), length = length(colors))
y <-
2009 Oct 26
1
regular expressions
Dear list,
I have the following text to parse (originating from readLines as some
lines have unequal size),
st = c("START text1 1 text2 2.3", "whatever intermediate text", "START
text1 23.4 text2 3.1415")
from which I'd like to extract the lines starting with "START", and
group the subsequent fields in a data.frame in this format:
text1 text2
2010 Aug 27
2
export 4D data as povray density files
Dear list,
I wish to visualise some 4D data as a kind of colour / translucent
cloud in 3D. I haven't seen such plots in R (but perhaps I missed a
feature of rgl). The easiest option I found would be to export the
data in povray's df3 (density file) format and visualise it with
povray.
The format specification baffles me a little,
http://www.povray.org/documentation/view/3.6.1/374/ ;
2010 Mar 10
4
write.fortran
Dear all,
I'm trying to write tabular data to a text file, these data will be
the input of a Fortran program. The format needs to be
"(i7,2x,7(e15.7,2x))". I have not been able to find a clean way of
producing this output with write.table. I searched for a
"write.fortran" function similar to read.fortran() in package utils
but I couldn't find any. Below is a small