Displaying 20 results from an estimated 4000 matches similar to: "Elementary sapply question"
2004 Jun 22
1
RE: summaries (was: SUMMARY: "elementary sapply question")
Ajay,
thank you very much for picking up that age-old habit of
posting summaries.
It existed years ago on s-help and I find it is still a great
thing: I would not have bothered to read your original question
nor the answers you got, but I did read the summary -- and I
learned something quite interesting!
Maybe some others who receive multiple non-elementary answers to their
questions could
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
2004 Feb 19
6
R for economists (was: Almost Ideal Demand System)
Hi,
I did not find any web page about using R in economics and econometrics so
far. However, this does not mean that there is none (searching with google
for "R" and "economics" gives many pages about economics and a name like
Firstname R. Lastname on it ;-)).
Does anybody in the list does know such a web page?
If not, I will be happy if you, Ajay, could build and
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
2004 Jun 17
2
Question on lists and vectors of lists
I have an elementary programming question. Could someone please point
me in the right direction?
I have a function which will run for thousands of companies. At each
invocation, it returns 2 numbers. I plan to do something like:
think_one_firm <- function(filename) {
# Do stuff
return(list(x=x,y=y))
}
So for each of the firms in my dataset, I will call
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
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
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
2004 Feb 23
6
Need help on parsing dates
I know this:
> library(date)
> x="1979-04-04"
> try=as.date(x, "ymd")
> print(try)
[1] 4Apr79
and that `x' here has to be a string, e.g.:
> x=1979-04-04
> print(x)
[1] 1971
I'm stuck in reading from a file. I say:
> A <- read.table(file="try")
> print(A)
V1 V2
1 1979-04-04
2004 Apr 21
2
Question on CAR appendix on NLS
The PDF file on the web, which is an appendix on nonlinear regression
associated with the CAR book, is very nice.
When I ran through the code presented there, I found something
odd. The code does a certain model in 3 ways: Vanilla NLS (using
numerical differentation), Analytical derivatives (where the user
supplies the derivatives) and analytical derivatives (using automatic
differentiation). The
2005 Aug 19
1
Problem with get.hist.quote() in tseries
When using get.hist.quote(), I find the dates are broken. This is with
R 2.1.1 on Mac OS X `panther'.
> library(tseries)
Loading required package: quadprog
'tseries' version: 0.9-27
'tseries' is a package for time series analysis and computational
finance.
See 'library(help="tseries")' for details.
> x <-
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
2004 Mar 02
2
Stuck in trying to convert repetitive code into a function
Folks,
I have the following repetitive code which works correctly:
A = read.table(file="junior.csv", sep=",", col.names=c("date", "l"));
A$date = chron(as.character(A$date), format="m/d/y");
r.junior = levels2weeklyret(lastfriday, A$date, A$l);
plot(A$date, A$l, type="l", col="red", main="Junior levels")
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
2004 Mar 11
1
Difficulties in interaction between R and latex (prosper)
Hello, folks! I'm trying to use R as a graphics program, to make some
pretty graphs that will go into prosper slideshows.
I wrote this fragment, from the R manual, into a file demo.R:
x=seq(-3,3,0.1)
postscript("cm_test.eps", width = 4.0, height = 3.0,
horizontal = FALSE, onefile = FALSE, paper = "special",
family =
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
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
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
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
2006 Jan 22
6
Making a markov transition matrix
Folks,
I am holding a dataset where firms are observed for a fixed (and
small) set of years. The data is in "long" format - one record for one
firm for one point in time. A state variable is observed (a factor).
I wish to make a markov transition matrix about the time-series
evolution of that state variable. The code below does this. But it's
hardcoded to the specific years that I