Displaying 20 results from an estimated 1000 matches similar to: "Count matches of a sequence in a vector?"
2013 Jun 27
3
using "rollapply" to calculate a moving sum or running sum?
#using "rollapply" to calculate a moving sum or running sum?
#I am tryign to use rollapply to calcualte a moving sum? #I tried
rollapply and get the error message
#"Error in seq.default(start.at, NROW(data), by = by) :
# wrong sign in 'by' argument"
#example:
mymatrix <- ( matrix(data=1:100, nrow=5, ncol=20) )
mymatrix_cumsum <- ( matrix(data=NA, nrow=5,
2009 Mar 23
1
performance: zoo's rollapply() vs inline
zoo's rollapply() function appears to be extremely useful for plugging in a
function on-the-fly to run over a window. With inline, there is a lot more
coding and room for error, and the code is less portable because the user
has to have R compiling set up or it won't work.
However, rollapply() seems to be really slow. Several orders of magnitude
slower than inline, in fact. I don't
2010 Apr 09
3
"fill in" values between rollapply
Hi,
Sorry ahead of time for not including data with this question.
Using rollapply to calculate mean values for 5 day blocks, I'd use this:
Roll5mean <- rollapply(data, 5, mean, by=5, align = c("left"))
My question is, can someone tell me how to fill in the days between each of
these means with the previously calculated mean? If this doesn't make
sense, I will clarify and
2012 Jul 08
3
How to replace a column in a data frame with another one with a different size
Hello everyone,
I have a dataframe with 1 column and I'd like to replace that column
with a moving average.
Example:
> library('zoo')
> mydat <- seq_len(10)
> mydat
[1] 1 2 3 4 5 6 7 8 9 10
> df <- data.frame("V1" = mydat)
> df
V1
1 1
2 2
3 3
4 4
5 5
6 6
7 7
8 8
9 9
10 10
> df[df$V1 <- rollapply(df$V1, 3, mean)]
2010 Jan 13
1
Rollapply
Hi
I would like to understand how to extend the function (FUN) I am using in
rollapply below.
######################################
With the following simplified data, test1 yields parameters for a rolling
regression
data = data.frame(Xvar=c(70.67,70.54,69.87,69.51,70.69,72.66,72.65,73.36),
Yvar =c(78.01,77.07,77.35,76.72,77.49,78.70,77.78,79.58))
data.z = zoo(d)
test1 =
2011 Dec 02
2
Moving column averaging
# need zoo to use rollapply()
# your data (I called df)
df <- structure(list(a = 1:2, b = 2:3, c = c(5L, 9L), d = c(9L, 6L),
e = c(1L, 5L), f = c(4, 7)), .Names = c("a", "b", "c", "d",
"e", "f"), class = "data.frame", row.names = c(NA, -2L))
# transpose and make a zoo object
df2 <- zoo(t(df))
#rollapply to get
2010 Jul 13
2
Zoo - bug ???
Hi folks,
I am confused whether the following is a bug or it is fine
Here is the explanation
a <- zoo(c(NA,1:9),1:10)
Now If I do
rollapply(a,FUN=mean,width=3,align="right")
I get
> rollapply(a,FUN=mean,width=3,align="right")
3 4 5 6 7 8 9 10
NA NA NA NA NA NA NA NA
But I shouldn't be getting NA right ? i.e for index 10 I should get
(1/3)*(9+8+7)
2008 Jul 31
1
rollapply() to portions of a matrix
Hi everyone,
I have a rollapply statement that applies a function, in steps, over a data
matrix as follows:
#Code start
testm<-rollapply(mat, 100, by=100, min, na.rm=F)
#Code end
This moves down matrix 'mat' and calculates the minimum value over a 100 row
range, every 100 rows (i.e. no overlaps). NAs are not removed.
I want to modify this statement somehow so that the rollapply()
2009 Jul 07
1
Error in Rolling window of function - rollapply
Dear Colleagues,
I have faced with the problem that function rollaply with rolling window for
calculation of volatility doesn't give the all results of calculations.
I have run the rolling window for calculation in Excel and obtained that the
number of outputs for Excel is 36 and for R is 18. The total number of
observations is 37. In the attachment you can find pdf of the Excel and
Excel
2011 Apr 09
5
Yearly aggregates and matrices
Hi,
I need to perform calculations on subsets of a data frame:
DF = data.frame(read.table(textConnection(" A B C D E F
1 a 1995 0 4 1
2 a 1997 1 1 3
3 b 1995 3 7 0
4 b 1996 1 2 3
5 b 1997 1 2 3
6 b 1998 6 0 0
7 b 1999 3 7 0
8 c 1997 1 2 3
9 c 1998 1 2 3
10 c 1999 6 0 0
11 d 1999 3 7 0
12 e 1995 1 2 3
13 e 1998 1 2 3
14 e 1999 6
2006 Oct 03
2
maybe use voronoi.findrejectsites?
hi all members,
please, i need you help... now a i´m working with veronoi polygons in a
area with projections, but i need cut the polygons left. On other words, i
need cut the polygons in the worked area.
R help say that use the command voronoi.findrejectsites, but in this
command i need put the numbers, any way...this command not cut!! do you
can help me?
Thank you for help me!
José Bustos
2011 Apr 03
1
zoo:rollapply by multiple grouping factors
# Hi there,
# I am trying to apply a function over a moving-window for a large
number of multivariate time-series that are grouped in a nested set of
factors. I have spent a few days searching for solutions with no luck,
so any suggestions are much appreciated.
# The data I have are for the abundance dynamics of multiple species
observed in multiple fixed plots at multiple sites. (I total I
2010 Apr 02
1
All sub-summands of a vector
Hello,
I'd like to take all possible sub-summands of a vector in the quickest and
most efficient way possible. By "sub-summands" I mean for each sub-vector,
take its sum. Which is to say: if I had the vector
x<-1:4
I'd want the "sum" of x[1], x[2], etc. And then the sum of x[1:2], x[2:3],
etc. And then...so on.
The result would be:
1 2 3 4
2 5 7
6 9
10
I can
2009 Jun 19
1
function rollapply
Hi,
I faced with problem when start using function - rollapply(returns, 3 ,
mean)
Error in UseMethod("rollapply") :
No suitable Method for "rollaply"
How can I fix the problem? Thank you for help.
--
Best regards,
Andy Fetsun
[[alternative HTML version deleted]]
2011 Aug 12
2
rollapply.zoo() with na.rm=TRUE
Hi.
I'm comparing output from rollapply.zoo, as produced by two versions
of R and package zoo. I'm illustrating with an example from a R-help
posting 'Zoo - bug ???' dated 2010-07-13.
My question is not about the first version, or the questions raised in
that posting, because the behaviour is as documented. I'm puzzled as
to why na.rm no longer is passed to mean, i.e. why
2011 Mar 04
2
apply.rolling() to a multi column timeSeries
Hello there,
I am trying to compute the 3 months return momentum with the timeSeries x.ts,
which is just a subset of simple returns from a much bigger series,
> class(x.ts)
[1] "timeSeries"
attr(,"package")
[1] "timeSeries"
> dim(x.ts)
[1] 20 3
> x.ts[1:8,]
GMT
MS.US AAPL.US CA.FP
1996-01-31 0.15159065 -0.133391894
2012 Oct 26
1
rollapply() by time, not entries (width)
Hi all-
Thank you for reading my post. Please bear in mind that I'm very much a
newbie with R! My question is this:
I'm trying to use rollapply() on an irregular time series so I can't simply
use the width parameter (I don't think). Rather than last 5 entries, I'd
like to rollapply on last 6 months (for example). What would be the proper
course of action for this?
Thanks!
2011 Mar 10
1
Moving window per group
Hi,
I have a data.frame of the following type:
F = data.frame(read.table(textConnection(" A B
1 1 4
2 1 3
3 1 1
4 1 4
5 1 2
6 1 2
7 1 2
8 2 1
9 2 1
10 2 1
11 2 1
12 3 2
13 3 4
14 3 1
15 3 1
16 3 1"),head=TRUE,stringsAsFactors=FALSE))
F
A B
1 1 4
2 1 3
3 1 1
4 1 4
5 1 2
6 1 2
7 1 2
8 2 1
9 2 1
10 2 1
11 2 1
12 3 2
13 3 4
14 3 1
15 3 1
16 3 1
2009 Nov 27
2
How to compute Rolling analysis of Standard Deviation using ZOO package?
Hello:
I want to get a rolling estimation of the stdev of my data.
Searching the document, I found the function "rollapply" in the zoo package.
For example, my series is "c", and i want get a period of 10 days,
so i write the command below:
roll.sd = rollapply( c, 10, sd, na.pad = TRUE, align = 'right' )
but there is an error in it ,and the computing cannot be
2010 Oct 28
4
Returning highs and lows in R
I'm having trouble returning a rolling n period highest value for a data
set. For each day I want to calculate the highest value over the last 3
days. I am using the following packages: zoo, xts, quantmod and TTR.
Thanks, Jason
GLD.Close
2010-10-01 128.91
2010-10-04 128.46
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2010-10-06 131.81
2010-10-07 130.37
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2010-10-11