Displaying 20 results from an estimated 2000 matches similar to: "`its' questions"
2004 Aug 25
1
Difficulties in starting up with its package
Folks,
I'm trying to learn `its' and am stuck on many basics. Could you
please help? I am on R 1.9.1 (2004-06-21) on Linux 2.4.17 #2. My its
version says
Packaged: Tue Apr 27 13:38:25 2004; HeywoodG
Built: R 1.9.0; ; 2004-04-28 15:03:13; unix
This part flows fine --
library(its)
x1 <- newIts(start="2000-01-01", end="2000-01-10", 1:30, ncol=3)
print(x1)
2004 Mar 03
5
get.hist.quote - is great, but am I missing something?
I find it's just great to be able to say:
library(tseries)
x <- get.hist.quote(instrument="ongc.ns")
and it gets a full time-series of the stock price of the symbol
ongc.ns from Yahoo quote.
However, once my hopes have been raised by such beauty :-) I get
disappointed when I do
> plot(x)
and the annotation is horrible! The x axis is not labelled as
dates. The default
2004 Mar 01
6
Find out the day of week for a chron object?
I know that this is correct:
library(chron)
x = dates("01-03-04", format="d-m-y", out.format="day mon year")
print(x)
It gives me the string "01 Mar 2004" which is correct.
I also know that I can say:
print(day.of.week(3,1,2004))
in which case he says 1, for today is monday.
My question is: How do I combine these two!? :-) I have a
2008 Mar 17
4
How does one do simple string concatenation?
How does one convert objects c("a","b","c") and "d" into "abcd"?
> paste(c("a","b","c"), "d")
of course yields
[1] "a d" "b d" "c d"
--
Ajay Shah http://www.mayin.org/ajayshah
ajayshah at mayin.org
2008 Oct 15
2
"Heuristic optimisation"?
I wondered was people on this list felt about this article:
http://www.voxeu.org/index.php?q=node/2363
which talks about the problems of obtaining sound answers in numerical
optimisation in settings such as MLE or NLS.
--
Ajay Shah http://www.mayin.org/ajayshah
ajayshah at mayin.org http://ajayshahblog.blogspot.com
<*(:-? -
2008 Mar 18
3
Puzzled at generating combinations
I have two data frames. Suppose the first has rows
r1
r2
r3
and the second has rows
R1
R2
R3
I'd like to generate the data frame:
r1 R1
r1 R2
r1 R3
r2 R1
r2 R2
r2 R3
r3 R1
r3 R2
r3 R3
How would I go about doing this? I'm sure there's a clean way to do it
but I find myself thinking in loops.
--
Ajay Shah
2006 Mar 06
3
Interleaving elements of two vectors?
Suppose one has
x <- c(1, 2, 7, 9, 14)
y <- c(71, 72, 77)
How would one write an R function which alternates between elements of
one vector and the next? In other words, one wants
z <- c(x[1], y[1], x[2], y[2], x[3], y[3], x[4], y[4], x[5], y[5])
I couldn't think of a clever and general way to write this. I am aware
of gdata::interleave() but it deals
2004 May 27
3
Date parsing question
How do I parse a date "yyyymmdd"? I tried asking chron(s, "ymd") but
that didn't work. Would the date parsing routines of the Date class of
1.9 grok this?
--
Ajay Shah Consultant
ajayshah at mayin.org Department of Economic Affairs
http://www.mayin.org/ajayshah Ministry of Finance, New Delhi
2006 Jan 26
2
Prediction when using orthogonal polynomials in regression
Folks,
I'm doing fine with using orthogonal polynomials in a regression context:
# We will deal with noisy data from the d.g.p. y = sin(x) + e
x <- seq(0, 3.141592654, length.out=20)
y <- sin(x) + 0.1*rnorm(10)
d <- lm(y ~ poly(x, 4))
plot(x, y, type="l"); lines(x, d$fitted.values, col="blue") # Fits great!
all.equal(as.numeric(d$coefficients[1] + m
2008 Mar 07
4
Reading microsoft .xls format and openoffice OpenDocument files
1. I have used gdata::read.xls() with much happiness. But every now
and then it breaks. I have not, as yet, been able to construct a
mental model about the class of .xls files for which it works. Does
someone have a simple rule for predicting the circumstances under
which it will work?
2. Just like there is a read.xls(), it'd be great if we have a
read.ods() which directly
2009 Oct 17
2
How do I access with the name of a (passed) function
How would I do something like this:
f <- function(x, g) {
s <- as.character(g) # THIS DOES NOT WORK
sprintf("The %s of x is %.0f\n", s, g(x))
}
f(c(2,3,4), "median")
f(c(2,3,4), "mean")
and get the results
"The median of x is 3"
"The mean of x is 3"
--
Ajay Shah
2004 Jun 21
2
Elementary sapply question
I am discovering sapply! :-) Could you please help me with a very
elementary question?
Here is what I know. The following two programs generate the same answer.
--------------------------------+----------------------------------------
Loops version | sapply version
--------------------------------+----------------------------------------
2004 Jul 05
2
More difficulties in getting data into R
In order to get around the problems of my posting a few minutes ago, I
thought:
$ awk -F\| '(NR > 2) {print $2}' cmie_firm_data.text > col2
$ awk -F\| '(NR > 2) {print $4}' cmie_firm_data.text > col4
$ paste col2 col4 | head -2
-510.45 -510.27
60700 101900
$ paste col2 col4 | tail -2
28648.12 31617.02
491014.77 494308.52
$ wc -l col2 col4
89323 col2
2005 May 27
1
R commandline editor question
I am using R 2.1 on Apple OS X.
When I get the ">" prompt, I find it works well with emacs commandline
editing. Keys like M-f C-k etc. work fine.
The one thing that I really yearn for, which is missing, is bracket
matching When I am doing something which ends in )))) it is really
useful to have emacs or vi-style bracket matching, so as to be able
to visually keep track of whether I
2007 Dec 19
1
Code for articles in R news?
I went to the article on np in R news 7/2 (October 2007). What's the
general technique to get the source code associated with the article
as a .R file that I can play with?
--
Ajay Shah http://www.mayin.org/ajayshah
ajayshah at mayin.org http://ajayshahblog.blogspot.com
<*(:-? - wizard who doesn't know the answer.
2008 Mar 05
1
New data source - now how do we build an R interface?
Folks,
A nice new data resource has come up -- http://data.un.org/
I thought it would be wonderful to setup an R function like
tseries::get.hist.quote() which would be able to pull in some or all
of this data.
I walked around a bit of it and I'm not able to map the resources to
predictable URLs which can then be wget. There's some javascript going
on that I'm not understanding.
2008 Dec 26
1
Question about regression without an intercept
Consider this code fragment:
---------------------------------------------------------------------------
set.seed(42)
x <- runif(20)
y <- 2 + 3*x + rnorm(20)
m1 <- lm(y ~ x)
m2 <- lm(y ~ -1 + x)
summary(m1)
summary(m2)
cor(y, fitted.values(m1))^2
cor(y, fitted.values(m2))^2
---------------------------------------------------------------------------
m1 is the
2005 May 08
2
Need a factor level even though there are no observations
I'm in this situation:
factorlabels <- c("School", "College", "Beyond")
with data for 8 families:
education.man <- c(1,2,1,2,1,2,1,2) # Note : no "3" values
education.wife <- c(1,2,3,1,2,3,1,2) # 1,2,3 are all present.
My goal is to create this table:
School College Beyond
2007 Oct 09
3
How do I obtain the design matrix of an lm()?
I am using the clever formula notation of R to first do an OLS. E.g. I
say
m <- lm(y ~ x + f)
where f is a factor, and R automatically constructs the dummy
variables. Very nice.
I need to then go on to do some other ML estimation using the same
design matrix that's used for the OLS. I could, of course, do this
manually. But it seems that lm() has done all this hard work. I wonder
if
2004 Oct 03
3
Making a 'joint distribution'?
Suppose I make two discrete variables --
> D <- data.frame(f1=sample(1:5,100,replace=T), f2=sample(1:5,100,replace=T))
I know I can do:
> table(D$f1, D$f2)
0 1 2 3 4
0 5 5 5 5 4
1 4 2 6 7 3
2 5 3 5 3 6
3 3 1 3 1 2
4 6 4 3 3 6
> table(D$f1)
0 1 2 3 4
24 22 22 10 22
> table(D$f2)
0 1 2 3 4
23 15 22 19 21
which is all great. But how do I produce the