Displaying 20 results from an estimated 2000 matches similar to: "when to use `which'?"
2006 May 11
3
cannot turn some columns in a data frame into factors
Hi,
I have a data frame df and a list of names of columns that I want to
turn into factors:
df.names <- attr(df,"names")
sapply(factors, function (name) {
pos <- match(name,df.names)
if (is.na(pos)) stop(paste(name,": no such column\n"))
df[[pos]] <- factor(df[[pos]])
cat(name,"(",pos,"):",is.factor(df[[pos]]),"\n")
2011 Jul 11
1
plot means ?
Hi,
I need this plot:
given: x,y - numerical vectors of length N
plot xi vs mean(yj such that |xj - xi|<epsilon)
(running mean?)
alternatively, discretize X as if for histogram plotting and plot mean y
over the center of the histogram group.
is there a simple way?
thanks!
--
Sam Steingold (http://sds.podval.org/) on CentOS release 5.6 (Final) X 11.0.60900031
http://thereligionofpeace.com
2012 Mar 14
2
sum(hist$density) == 2 ?!
> x <- rnorm(1000)
> h <- hist(x,plot=FALSE)
> sum(h$density)
[1] 2 ----------------------------- shouldn't it be 1?!
> h <- hist(x,plot=FALSE, breaks=(-4:4))
> sum(h$density)
[1] 1 ----------------------------- now it's 1. why?!
--
Sam Steingold (http://sds.podval.org/) on Ubuntu 11.10 (oneiric) X 11.0.11004000
http://www.childpsy.net/ http://www.memritv.org
2017 Nov 09
2
[R-pkgs] Release of ess 0.0.1
> * Jorge Cimentada <pvzragnqnw at tznvy.pbz> [2017-11-09 00:02:53 +0100]:
>
> I'm happy to announce the release of ess 0.0.1 a package designed to
> download data from the European Social Survey
Given the existence of ESS (Emacs Speaks Statistics -
https://ess.r-project.org/) the package name "ess" seems unfortunate.
--
Sam Steingold (http://sds.podval.org/) on
2011 Jul 12
1
how to find out whether a string is a factor?
I have two data frames:
> str(ysmd)
'data.frame': 8325 obs. of 6 variables:
$ X.stock : Factor w/ 8325 levels "A","AA","AA-",..: 2702 6547 4118 7664 7587 6350 3341 5640 5107 7589 ...
$ market.cap : num -1.00 2.97e+10 3.54e+08 3.46e+08 -1.00 ...
$ X52.week.low : num 40.2 22.5 27.5 12.2 20.7 ...
$
2006 Mar 17
6
removing NA from a data frame
Hi,
It appears that deal does not support missing values (NA), so I need to
remove them (NAs) from my data frame.
how do I do this?
(I am very new to R, so a detailed step-by-step
explanation with code samples would be nice).
Some columns (variables) have quite a few NAs, so I would rather drop
the whole column than sacrifice all the rows (observations) which have
NA in that column.
How do I
2012 Oct 18
3
how to concatenate factor vectors?
How do I concatenate two vectors of factors?
--8<---------------cut here---------------start------------->8---
> a <- factor(5:1,levels=1:9)
> b <- factor(9:1,levels=1:9)
> str(c(a,b))
int [1:14] 5 4 3 2 1 9 8 7 6 5 ...
> str(unlist(list(a,b),use.names=FALSE))
Factor w/ 9 levels "1","2","3","4",..: 5 4 3 2 1 9 8 7 6 5 ...
2011 Aug 16
2
merge(join) problem
I have two datasets:
A with columns Open and Name (and many others, irrelevant to the merge)
B with columns Time and Name (and many others, irrelevant to the merge)
I want the dataset AB with all these columns
Open from A - a difftime (time of day)
Time from B - a difftime (time of day)
Name (same in A & B) - a factor, does NOT index rows, i.e., there are
_many_ rows in both A & B with
2012 Aug 30
3
apply --> data.frame
Is there a way for an apply-type function to return a data frame?
the closest thing I think of is
foo <- as.data.frame(sapply(...))
names(foo) <- c(....)
is there a more "elegant" way?
Thanks!
--
Sam Steingold (http://sds.podval.org/) on Ubuntu 12.04 (precise) X 11.0.11103000
http://www.childpsy.net/ http://palestinefacts.org http://dhimmi.com
http://honestreporting.com
2012 Aug 15
3
per-vertex statistics of edge weights
I have a graph with edge and vertex weights, stored in two data frames:
--8<---------------cut here---------------start------------->8---
vertices <- data.frame(vertex=c("a","b","c","d"),weight=c(1,2,1,3))
edges <-
2012 Feb 08
4
"unsparse" a vector
Suppose I have a vector of strings:
c("A1B2","A3C4","B5","C6A7B8")
[1] "A1B2" "A3C4" "B5" "C6A7B8"
where each string is a sequence of <column><value> pairs
(fixed width, in this example both value and name are 1 character, in
reality the column name is 6 chars and value is 2 digits).
I need to
2013 Jan 18
5
select rows with identical columns from a data frame
I have a data frame with several columns.
I want to select the rows with no NAs (as with complete.cases)
and all columns identical.
E.g., for
--8<---------------cut here---------------start------------->8---
> f <- data.frame(a=c(1,NA,NA,4),b=c(1,NA,3,40),c=c(1,NA,5,40))
> f
a b c
1 1 1 1
2 NA NA NA
3 NA 3 5
4 4 40 40
--8<---------------cut
2012 Dec 04
3
list to matrix?
How do I convert a list to a matrix?
--8<---------------cut here---------------start------------->8---
list(c(50000, 101), c(1e+05, 46), c(150000, 31), c(2e+05, 17),
c(250000, 19), c(3e+05, 11), c(350000, 12), c(4e+05, 25),
c(450000, 19), c(5e+05, 16))
as.matrix(a)
[,1]
[1,] Numeric,2
[2,] Numeric,2
[3,] Numeric,2
[4,] Numeric,2
[5,] Numeric,2
[6,] Numeric,2
[7,]
2012 Nov 19
2
generated list element names
How can I create lists with element names created on the fly?
--8<---------------cut here---------------start------------->8---
> list (foo = 10)
$foo
[1] 10
> list ("foo" = 10)
$foo
[1] 10
> list (paste("f","oo",sep="") = 10)
Error: unexpected '=' in "list (paste("f","oo",sep="") ="
2012 Aug 28
5
variable scope
At the end of a for loop its variables are still present:
for (i in 1:10) {
x <- vector(length=100000000)
}
ls()
will print "i" and "x".
this means that at the end of the for loop body I have to write
rm(x)
gc()
is there a more elegant way to handle this?
Thanks.
--
Sam Steingold (http://sds.podval.org/) on Ubuntu 12.04 (precise) X 11.0.11103000
2012 Oct 16
5
uniq -c
I need an analogue of "uniq -c" for a data frame.
xtabs(), although dog slow, would have footed the bill nicely:
--8<---------------cut here---------------start------------->8---
> x <- data.frame(a=1:32,b=1:32,c=1:32,d=1:32,e=1:32)
> system.time(subset(as.data.frame(xtabs( ~. , x )), Freq != 0 ))
user system elapsed
12.788 4.288 17.224
--8<---------------cut
2013 Sep 18
2
strsplit with a vector split argument
Hi,
I find this behavior unexpected:
--8<---------------cut here---------------start------------->8---
> strsplit(c("a,b;c","d;e,f"),c(",",";"))
[[1]]
[1] "a" "b;c"
[[2]]
[1] "d" "e,f"
--8<---------------cut here---------------end--------------->8---
I thought that it should be identical to this:
2011 Feb 15
4
string parsing
I am trying to get stock metadata from Yahoo finance (or maybe there is
a better source?)
here is what I did so far:
yahoo.url <- "http://finance.yahoo.com/d/quotes.csv?f=j1jka2&s=";
stocks <- c("IBM","NOIZ","MSFT","LNN","C","BODY","F"); # just some samples
socket <-
2012 Aug 27
1
write.matrix.csr data conversion
> write.matrix.csr(mx, y = y, file = file)
> table(y)
0 1
5194394 23487
$ cut -d' ' -f1 f | sort | uniq -c
23487 2
5194394 1
i.e., 0 is written as 1 and 1 is written as 2.
why?
is there a way to disable this?
--
Sam Steingold (http://sds.podval.org/) on Ubuntu 12.04 (precise) X 11.0.11103000
http://www.childpsy.net/ http://palestinefacts.org
2011 Feb 15
1
all.equal: subscript out of bounds
When I do
> all(all$X.Time == all$Y.Time);
[1] TRUE
as expected, but
> all.equal(all$X.Time,all$Y.Time);
Error in target[[i]] : subscript out of bounds
why?
thanks!
--
Sam Steingold (http://sds.podval.org/) on CentOS release 5.3 (Final)
http://mideasttruth.com http://honestreporting.com http://dhimmi.com
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The dark past once was the