Displaying 20 results from an estimated 20000 matches similar to: "lazy evaluation question"
2010 May 10
3
scope of a function + lazy evaluation
Hey guys,
I have a doubt here , It is something simple I guess, what am I missing out
here ??
f <- function(y) function() y
tmp <- vector("list", 5)
for (i in 1:5) tmp[[i]] <- f(i)
tmp[[1]]() # returns 5;
z <- f(6)
tmp[[1]]() # still returns 5; it should return 6 "ideally" right ???
Even if I dont evaluate the function tmp[[1]] before i.e I do
rm(list=ls())
f
2009 Aug 05
4
A question regarding R scoping
I have a question related to scoping. Suppose we have 2 functions:
f1 = function(i){i = 1}
f2 = function(n){
i = length(n)
f1(i)
}
In other words, I would like i=1 regardless of n. Is this possible without having f1 in the body of f2? Thanks in advance!
2009 Jan 28
1
evaluation revisited
I'm still going over old emails and trying to get my head around
evaluation so I'm persistent if nothing else.
A while back , an expert sent me below as an exercise in understanding
and I only got around to it tonight. I understand some of the output but
not all of it and I put "Why not Zero ?" next to the ones that I don't
understand based on my reading of the various
2009 Mar 31
1
error when going through Alan Lenarcic's package Tutorial
Hi Everyone: I've been going through Alan Lenarcic's package tutorial but
when I did
R CMD SHLIB Xdemo.cc Xdemo_main.cc -o Xdemo.dll
I got the following error:
XDemo_res.rc:15:38: warning: missing terminating " character
XDemo_res.rc:23:34: warning: missing terminating ' character
c:\mark\research\Rtools\MinGW\bin\windres.exe: XDemo_res.rc:16: syntax error
2008 Sep 23
4
perl expression question
If I have the string below. does someone know a regular expression to
just get the "BLC.NYSE". I bought the O'Reilley
book and read it when I can and I study the solutions on the list but
I'm still not self sufficient with these things. Thanks.
stock<-"/opt/limsrv/mark/research/equity/projects/testDL/stock_data/fhdb/US/BLC.NYSE"
2009 Nov 13
4
processing log file
Dear all, I'm trying to process a log file which logs the date, the username and the computer number accessed. The table looks like this:
>table.users
Date UserName Machine
1 2008-11-25 John 641
2 2008-11-25 Clive 611
3 2008-11-25 Jeremy 641
4 2008-11-25 Walt 722
5 2008-11-25 Tony 645
6 2008-11-26 Tony 645
7 2008-11-26
2012 May 14
2
Inf and lazy evaluation
Hi,
I have a question involving Inf, lazy evaluation, and maybe argument
recycling. I have a directory where I am trying to check for the
existence of files of a certain pattern, basically something like
"filename-#", where # is an integer. I can do something like this,
which works.
file.exists(paste(filename, "-", 1:100, sep = ""))
But I don't like the fact
2006 Jun 16
2
scatterplot but a little tricky
i have two vectors of numbers x and y and of course i
can do the standard scatterplot plot(x,y)
and it looks fine. But, I was hoping there was a way to
do the scatterplot so that each point plotted is a number
where the number represents the index in the dataset.
so, if it was x[3] and y[3], then the point would be a 3
or if it was x[4] and y[4], then the point would be a 4 etc.
i doubt this is
2006 Jul 05
2
apologes if you already saw this :efficiency question
hi everyone : i'm not sure if my previous mail about
this got sent. i was typing and
erroneosuyl hit a button and lost what i was typing.
anyway, i have the code below ( it works ) in which i run through the rows of a dataframe, taking out the first two
fields which are characters strings ( with some extra spacing so
i yuse gsub) and appending these character strings to a list so that i can
2006 Jul 06
2
[Fwd: as.data.frame question]
>From: markleeds at verizon.net
>Date: Thu Jul 06 13:16:42 CDT 2006
>To: markleeds at verizon.net
>Subject: as.data.frame question
>hi all : as a result of an lapply command,
>i get the following output.
>
>
>$AAA
> 000106 000107 000108
> 5.5 6.5 3.0
>
>$BBB
> 000106 000107 000108
> 4 5 6
>
>$CCC
2009 Jun 01
1
Fwd: subset dataframe/list
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Subject: Re: [R] subset dataframe/list
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2008 Jul 05
3
trying to superimpose a line plot onto a histogram
Hello,
I'm trying to superimpose a line plot onto a histogram but I'm not having
any luck. I've attached the dataset. What I did was:
> hist(data,freq=F)
Now I'm trying to superimpose the following points with a line connecting
them onto the histogram:
x y
100 0.535665393824959
200 0.212744329736556
300 0.0844933242968584
400 0.0335572838043417
500
2001 Mar 22
1
lazy evaluation and DUP=F
I am having some difficulty understanding the implication of lazy evaluation mixed
with DUP=F in a .Fortran call. In qr.qty from base DUP is not used as an argument so
defaults to T. I am calling qr.qty with a very large array and would like to set
DUP=F in the .Fortran call so that qr.qty would be defined as copied below. Is there
some risk that a variable used as the argument in the original
2009 Apr 01
1
problems with package tutorial
Hi: Here's my revised attempt at explaining my problem. Hopefully it won't
get sent out weirdly like it did earlier. ? The link to what I'm trying to
follow is
http://www.stat.columbia.edu/~gelman/stuff_for_blog/AlanRPackageTutorial.pdf
? I've been going through the tutorial but when I got to page 9 and did
R CMD SHLIB Xdemo.cc Xdemo_main.cc -o Xdemo.dll
I got
2009 Feb 05
4
eval and as.name
I'm sure there is a more general way to ask this question but how do
you use the elements of a character vector as names of objects in an
expression?
For example, say you have:
a = c(1,3,5,7)
b = c(2,4,6,8)
n=c("a","b")
and you want to use the names a and b in a function (e.g. sum)
sum(eval(as.name(n[1])),eval(as.name(n[2])))
works but
what is a simpler way to
2009 Feb 11
2
error in my previous message
i'm sorry. i had an error in my previous code because i left out a
letter in the rownames.
while fixing that, i also found a solution. so i'm sorry for the
confusion.
below is my fix.
temp2 <- matrix(rnorm(10),nc=1,nrow=10)
rownames(temp2) <-
2006 Jun 20
2
strange use of sapply
I've tried and give up. I have a matrix of say 200 columns and 400 rows.
For each odd ( or even i suppose if i wanted to )column,
I want to know the number of rows in which the value is greater than zero.
So, I did sapply(tempMatrix,2,function(x) sum( x > 0 ))
this almost works but i don't know how to tell
it to only do the odd columns. my guess is , like everything else
in R, this
2008 May 01
2
regular expression question
I have strings of the form
TICKER.GGG.XXXXXX.dat
but GGG is not always three characters so I can't use substr to pull it
out of the string.
Could someone tell me how to use sub to pull out the GGG but more
generally the string between the dot after the R in TICKER and the next
dot. I still don't have a very good understanding of regular
expressions but I'm trying to get that
2009 Aug 20
2
Problem using findVar( ) in combination with R's lazy evaluation
Hi All,
I have a few small questions about the usage of the C findVar( ) function
when used in C code called with '.Call'. In my case I create an R function
with an argument. This function calls some C code in which I use findVar( )
to retrieve the values from the argument. Ofcourse normally I would just
give the values as argument to .Call, but in my project I need to use
findVar for
2009 Mar 03
4
regular expression question
can someone show me how to use a regular expression to break the string
at the bottom up into its three components :
(-0.791,-0.263]
(-38,-1.24]
(0.96,2.43]
I tried to use strplit because of my regexpitis ( it's not curable. i've
been to many doctors all over NYC. they tell me there's no cure ) but
it doesn't work because there also dots inside the brackets. Thanks.