Displaying 20 results from an estimated 10000 matches similar to: "how to extract data by specific months from a monthly ts object"
2010 Jan 31
0
Package ismev, gpd.fit, and interpretation for statistics of extreme values
Dear All,
I have a question about package "ismev", its function "gpd.fit", and
interpretation of the results.
I used the package ismev to do an extreme value analysis on a fire
dataset. Two variables are used in the analysis. The focal variable is
acreage burned per fire, ranging from 1 to 5000 acres per fire. In
total, there are 69,980 observations. The date covers
2010 Sep 05
3
simple ts() object question
Dear Community,
say, I have an annual ts() object sampled from 1960 to 1969 like:
ta<-ts(1:10, start=1960, frequency=1)
How can I extract the value from the year 1965?
I mean, not by:
ta[6]
but by something like:
ta[1965]
where I'm directly referring to the year of the observation?
Thank you in advance!
--
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2012 Jul 23
1
mgcv: Extract random effects from gam model
Hi everyone,
I can't figure out how to extract by-factor random effect adjustments from a
gam model (mgcv package).
Example (from ?gam.vcomp):
library(mgcv)
set.seed(3)
dat <- gamSim(1,n=400,dist="normal",scale=2)
a <- factor(sample(1:10,400,replace=TRUE))
b <- factor(sample(1:7,400,replace=TRUE))
Xa <- model.matrix(~a-1) ## random main effects
Xb <-
2012 Dec 17
3
mean of each month in data
Dear R users,
[in case the format of email is changed or you dont finf it easy to understand, i have attached a text file of my question]
i have the data in the following format and i want to convert it in the
format given at the end.
Ta ans Sa are the names of certain cities. there are 69 cities in my
data.
column 1 is representing station name (i am writing the data of only
two cities for
2008 Jan 06
1
aggregate.ts help
Hi,
I have a ts object with a frequency of 4, i.e., quarterly data, and I would
like to calculate the mean for each quarter. So for example:
> ts.data=ts(1:20,start=c(1984,2),frequency=4)
> ts.data
Qtr1 Qtr2 Qtr3 Qtr4
1984 1 2 3
1985 4 5 6 7
1986 8 9 10 11
1987 12 13 14 15
1988 16 17 18 19
1989 20
If I do this manually, the mean
2012 Feb 09
1
Constraint on one of parameters.
Dear all,
I have a function to optimize for a set of parameters and want to set a
constraint on only one parameter. Here is my function. What I want to do is
estimate the parameters of a bivariate normal distribution where the
correlation has to be between -1 and 1. Would you please advise how to
revise it?
ex=function(s,prob,theta1,theta,xa,xb,xc,xd,t,delta) {
expo1=
2007 Oct 13
2
the use of the .C function
Dear All,
could someone please shed some light on the use of the .C or .Fortran function:
I am trying load and running on R the following function
// psi.cpp -- psi function for real arguments.
// Algorithms and coefficient values from "Computation of Special
// Functions", Zhang and Jin, John Wiley and Sons, 1996.
//
// (C) 2003, C. Bond. All rights reserved.
//
//
2006 Aug 02
1
RE
Hi any,
Can some please detail me the createX command in bayesm package?
To make things easy for you to help me, let me put forward my problem
Suppose I have 3 covariates (say X matrix) and my Y has 3 categories say
(1,2,3). Now from the CreateX I understand that the data matrix say 'Xa' must
be of dimension n* (naxp), where 'na' is the number of variables and 'p' is
2011 Aug 15
2
plotting segments only and in color
Hello,
I've a question concerning the display of interval data.
A sample dataset where X is an interval between Xa and Xb
which should be displayed:
Y=c(15,14,23,18,19,9,19,13)
Xa=c(17,22,21,18,19,25,8,19)
Xb=c(22,22,29,34,19,26,17,22)
X = (Xa+Xb)/2
It's easily possible to plot the mean of the interval like:
plot(X,Y)
afterwards I can create lines for the interval with:
2011 Mar 06
4
sorting & subsetting a data.frame
Dear all
This may be obvious, but I cannot get it working. I'm trying to subset
& sort a data frame in one go.
x <- iris
x$Species1 <- as.character(x$Species)
##subsetting alone works fine
with(x, x[Sepal.Length==6.7,])
##sorting alone works fine
with(x, x[order(Sepal.Length, rev(sort(Species1))),])
##gets subsetted, but not sorted as expected
with(x, x[(Sepal.Length==6.7) &
2004 Apr 25
1
ts's in lm()
Is this a bug?
seasonal.dummies <-
function(x, contr=NULL) {
# takes a time series and returns a matrix of seasonal dummies for
# x. This is almost cycle(x), we only have to make it into a factor
# and add suitable level names.
# return a matrix which includes a constant!
# level names here assumes frequency is 12!
cyc <- factor( cycle(x), labels=c("ene","feb",
2017 May 30
2
Pseudo-instruction that overwrites its input register
On Tue, 30 May 2017, Nemanja Ivanovic wrote:
> This is typically accomplished with something like PPC's `RegConstraint` and
> `NoEncode`. You can see examples of it that are very similar to what you're after in
> PPC's load/store with update forms (i.e. load a value and update the base register
> with the effective address - these are used for pre-increment loads/stores).
2013 Apr 16
1
avoid losing data.frame attributes on cbind()
Dear all,
How should I add several variables to a data frame without losing the
attributes of the df? Consider the following:
> require(Hmisc)
> Xa <- iris
> label(Xa, self=T) <- "Some df label"
> str(Xa)
'data.frame': 150 obs. of 5 variables:
$ Sepal.Length: num 5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ...
$ Sepal.Width : num 3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9
2011 Nov 22
5
x, y for point of intersection
Hi everyone,
?
I am trying to get a point of intersection between a
polyline and a straight line ?.. and get the x and y coordinates of this point.
For exemplification consider this:
?
?
set.seed(123)
?
k1 <-rnorm(100, mean=1.77, sd=3.33)
?k1 <- sort(k1)
q1 <- rnorm(100, mean=2.37, sd=0.74)
q1 <- sort(q1, decreasing = TRUE)
plot(k1, q1, xlim <- c((min(k1)-5),
2009 Nov 25
1
group generics
I have classes A and B, where B contains A. In the implementation of
the group generic for B I would like to use the corresponding group
generic for A. Is there a way to do that?
I would also appreciate any comments if what I'm trying to do seems like
the wrong approach.
Here's a stripped down example:
setClass("A",
2010 May 12
2
How to extract sum of particular months in a monthly data series
Dear Users,
I have a monthly data for a number of years(1960-2007) for a number of
stations and i wish to extract sesonal time-series for the months of
March-May and October-November for very station. I have read this data with
read.table in R with stations as columns and time (months) as rows. My
attempt to aggregate with the zoo package using the function as.yearqtr
failed since this sums
2011 Oct 10
4
correlation matrix
Hello Gurus
I have two correlation matrices 'xa' and 'xb'
set.seed(100)
d=cbind(x=rnorm(20)+1,
x1=rnorm(20)+1,
x2=rnorm(20)+1)
d1=cbind(x=rnorm(20)+2,
x1=rnorm(20)+2,
x2=rnorm(20)+2)
xa=cor(d,use='complete')
xb=cor(d1,use='complete')
I want to combine these two to get a third matrix which should have half
values from 'xa' and half
2012 Jul 10
3
fill 0-row data.frame with 1 line of NAs
Dear all
Is there a simpler method to achieve the following: When I obtain an
empty data.frame after subsetting, I need for it to contain one line
of NAs. Here's a dummy example:
> (.xb <- iris[ iris$Species=='zz', ])
[1] Sepal.Length Sepal.Width Petal.Length Petal.Width Species
<0 rows> (or 0-length row.names)
> dim(.xb)
[1] 0 5
> (.xa <-
2009 Mar 20
1
Mean-replacing NAs in a 3d array
Hi all
I have a 3d array containing missing values.
> Xa
, , 1
[,1] [,2]
[1,] 1 3
[2,] NA 4
, , 2
[,1] [,2]
[1,] 5 7
[2,] NA NA
, , 3
[,1] [,2]
[1,] 9 11
[2,] 10 12
I want to replace the missing values with the mean, but the mean of each
'page' in the array (wrong terminology I'm sure). So - for the array
above - [2,1,2] and
2004 Mar 10
3
converting lists got by tapply to dataframes
I have two lists:
xa <- list( X=c(1,2,3), Y=c(4,5,6), Z=c(7,8,9) )
xb <- with( barley, tapply( X=seq(1:nrow(barley)), INDEX=site
, FUN=function(z)yield[z]))
I can convert xa to a dataframe easily with:
as.data.frame(xa)
But if i try the same with xb I get:
as.data.frame(xb)
Error in as.data.frame.default(xb) :
can't coerce array into a data.frame
What