Displaying 20 results from an estimated 10000 matches similar to: "plot POSIXct format data"
2008 Feb 28
1
problem of subscript value from vector and list
Hi, everyone
I got some problems when trying to subscript the value of vector and
list, by using calculated indices.
Here is the vector I am generated
lon<-rep(0,886);lat<-rep(0,691)
for (i in 1:886){
lon[i]<-112+0.05*(i-1)
}
for (i in 691:1){
lat[i]<--44.5+0.05*(691-i)
}
For a given location of lon(xp) and lat(yp), I would like to calculate
the position of them,
2008 Mar 05
3
ipf function in R
Hi
I have a 3 x 2 contingency table:
10 20
30 40
50 60
I want to update the frequencies to new marginal totals:
100 130
40 80 110
I want to use the ipf (iterative proportional fitting) function which
is apparently in the cat package.
Can somebody please advice me how to input this data and invoke ipf in R
to obtain an updated contingency table?
Thanks.
By the way I am quite new to R.
--
Dr
2003 Mar 03
1
transition matrix problem
I'm having trouble using some fairly simple code to change the entries
in a vector (x - the numbers 0-5) according to a simple transition
matrix that I've called p.dry.
the error message I get is
"no finite arguments to min; returning Inf"
Any suggestions as to where I'm going wrong greatly appreciated. Sorry
the message is lengthy!
cheers
Nick
The code is
2010 May 15
1
conditional calculations per row (loop versus apply)
Hi all,
I'm hoping someone might help with a query about conditionally applying formulas to a dataframe.
In essence I have 3 lookup tables (Table A, B & C) and a dataframe with a variable Type.Code, which identifies the Lookup Table to which each record belongs. The lookup tables reference different sensor types for which I need apply a different formula to values in Column3 in each row
2008 Jan 15
1
Retrieve results from chisq.test programmatically
Hello,
I would like to run a series of chisq.test() and store results (x-square,
df, p-value) in a matrix for further analysis, but don't know how to do
such. Currently I run the command line for each set of data at a time and
it is time consuming.
Thank you for your help.
--My Coyne
[[alternative HTML version deleted]]
2012 May 20
5
removeing only rows/columns with "na" value from square ( symmetrical ) matrix.
I have some square matrices with na values in corresponding rows and
columns.
M<-matrix(1:2,10,10)
M[6,1:2]<-NA
M[10,9]<-NA
M<-as.matrix(as.dist(M))
print (M)
1 2 3 4 5 6 7 8 9 10
1 0 2 1 2 1 NA 1 2 1 2
2 2 0 1 2 1 NA 1 2 1 2
3 1 1 0 2 1 2 1 2 1 2
4 2 2 2 0 1 2 1 2 1 2
5 1 1 1 1 0 2 1 2 1 2
6 NA NA 2 2 2 0 1 2 1 2
7 1 1 1 1 1 1 0 2 1 2
8
2012 Apr 10
7
How to remove $ (Dollar sign) from string
How do I remove a "$" character from a string sub() and gsub() with "$" or
"\$" as pattern do not work.
> sub("$","","ABC$DEF")
[1] "ABC$DEF"
> sub("\$","","ABC$DEF")
Error: '\$' is an unrecognized escape in character string starting "\$"
>
2009 Dec 21
1
proposal for new axis.Date/axis.POSIXct
Hi R-devel.
I've noticed a couple of quirks in the current time/date axis
functions (axis.Date, axis.POSIXct, and the equivalents in lattice).
Looking at the code, it seems like a fairly ad-hoc approach, often
using pretty() on components of the time. This is not always ideal -
for example a one-hour interval gets cut into 10-minute chunks rather
than the more natural 15-minute chunks (since
2003 Feb 13
2
ROC
Hi, can you advise me is there any ROC(Receiver
Operating Characteristic)analysis program in R?
Thanks,
Dechao
=====
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Tel: (44) 01223 719718
Mob: (44) 07729 411134
__________________________________________________
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2009 Sep 11
1
What determines the unit of POSIXct differences?
Dear All,
what determines if a difference between POSIXct objects gets
expressed in days or seconds?
In the following example, it's sometimes seconds, sometimes days.
as.POSIXct('2009-09-01') - as.POSIXct(NA)
Time difference of NA secs
c(as.POSIXct('2009-09-01'), as.POSIXct(NA)) -
c(as.POSIXct('2009-09-01'), as.POSIXct('2009-08-31'))
Time differences in
2003 Jul 07
1
Problems with a dll under windows
I am trying to get a dll compiled for use with dyn.load. I use R.1.7.1
under Windows.
I have tried the following trivial example based on the "Writing R
extensions" manual.
rtest.h
--------
class X {
public:
X ();
~X ();
void Give7(double*);
};
class Y {
public: Y (); ~Y ();
};
rtest.cpp
---------
#include <iostream.h>
#include "rtest.h"
static Y y;
2018 May 16
2
Date method of as.POSIXct does not respect tz
R 3.5.0
Is it intended that the Date method of as.POSIXct does not respect the
tz parameter? I suggest changing as.POSIXct.Date to this:
function (x, tz = "", ...)
.POSIXct(unclass(x) * 86400, tz = tz)
Currently, the best workaround seems to be using the character method if
one doesn't want the default timezone (which is often an annoying DST
timezone).
This came up on
2012 Aug 24
1
POSIXct-coerced NA's not considered NA by is.na()
Hello folks,
I found a strangeness while experimenting with POSIXct vectors and
lists. It seems that coerced NA's aren't "real" NAs, at least as
considered by is.na()?
> date_vec = c(as.POSIXct(now()), as.POSIXct(now()+1),NA,"b")
> date_vec
[1] "2012-08-22 15:00:46 COT" "2012-08-22 15:00:47 COT" NA
[4] NA
Warning message:
In
2006 Oct 04
2
integers to POSIXct
What is the recommended way to convert/coerce and integer to a POSIXct
please?
d <- as.POSIXct(Sys.Date())
i <- as.integer(d)
as.POSIXct(i)
Error in as.POSIXct.default(i) : do not know how to convert 'i' to class
"POSIXlt"
This appears to be the behaviour in 2.3.1 and 2.4.0 on windows XP.
I have tried searching on this and found as.Date.integer in package zoo
which
2003 Jun 05
1
question about POSIXct conversion
Hello!
I am trying to compute minimal time on some data like this:
mt<-tapply(mrsh$time1,list(mrsh$var1,mrsh$var2),min):
a b
145 1054800600 1054789800
340 1054804500 1054794600
349 1054820400 1054792800
55 1054800600 1054789200
57 1054814100 1054791000
78 1054822200 1054790400
843
2003 Jan 22
1
Convert numeric value to POSIXct
Hi,
How do I convert a numeric value indicating the time since 1970, back into
a POSIXct class object? I have tried format.POSIXct and as.POSIXct
without success.
For example
> ccc
[1] "1945-01-01 15:00:00 MDT"
> ddd<- as.numeric(ccc);
> ddd
[1] -788842800
> format.POSIXct(ddd)
Error in format.POSIXct(ddd) : wrong class
> as.POSIXct(ddd)
Error in
2012 Jun 15
2
time zones and the chron to POSIXct conversion
Hey R folks,
i found some strange (to me) behaviour with chron to POSIXct conversion.
The two lines of code result in two different results, on ewith the
correct time zone, one without:
library(chron)
as.POSIXct(chron('12/12/2000'), tz = 'UTC')
as.POSIXlt(chron('12/12/2000'), tz = 'UTC')
Only the code below would give me a POSIXct object with the correct time
2012 Jan 19
2
POSIXct value display incorrect for some values
First, the reproducable example, showing how converting from character to
POSIXct to character changes the milliseconds in the first time stamp
though not in the second:
> as.POSIXct('2010-06-03 9:03:58.324')
[1] "2010-06-03 09:03:58.323 PDT"
> as.POSIXct('2010-06-03 9:03:58.325')
[1] "2010-06-03 09:03:58.325 PDT"
This seems to be due to truncation of
2003 Apr 30
2
ylab in plot.POSIXct
I am using R-1.7.0 and have some data which consist of one vector of
numbers and a second corresponding vector of dates belonging to the
POSIXct class. I would like to plot the numbers against the dates.
What is the best way to do this?
It almost works to just call `plot.' However if I do this while using
the `ylab' parameter I get a warning message:
parameter "ylab"
2003 Sep 02
1
convert character to POSIXct
Dear list-members,
I would like to calculate the difference between two points in time. To convert a 'time (GMT)'-character with the format "1/1/1999 01:01:01" into an object of class "POSIXct"', I first use the strptime() as suggested in the details help(as.POSIXct).
e.g.
starttime<-strptime("1/1/1999 01:01:01",format="%d/%m/%Y %H:%M:%S")