Displaying 20 results from an estimated 1200 matches similar to: "How to convert number (matlab) to date"
2011 Mar 13
4
readMat - how to retrieve the variables
Hello
I have a matlab MAT file that contains one single variable: a. The
structure of a is as follows:
a.river1.flow (flow values)
a.river1.date_flow (date)
a.river1.precip (precipitation values)
a.river1.date_precip
a.river2.flow
a.river2.date_flow
a.river2.precip
a.river2.date_precip
I have used readMat to load the variable a in R, however I have no idea how
readMat translates a. I managed
2005 Apr 22
2
help with POSIX
For the r script below
>datestr <- "01/01/2004"
>as.POSIXct(as.Date(datestr, "%d/%m/%Y"))
I get the following output
"2003-12-31 18:00:00 Central Standard Time"
Why is the date a day before. I guess its something to do with the time, but is there a way to get it to return 2004-01-01 instead?
Thanks in advance...
-Sandeep
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2007 Oct 16
1
try / tryCatch for download.file( ) within a for loop when URL does not exist
I am trying to download a bunch of files from a server, for which I am
using download.file( ) within a for loop. The script is working fine
except until download.file hits a URL which has no file, at which
point it exits. I want to change this behavior to simple log the
failure and maintain state within the for loop and iterate to next. I
read about try / tryCatch but am having trouble
2011 Aug 15
2
Regression - how to deal with past values?
Dear R-users
I need to fit a nonlinear model to a piece of data. The model to be fitted
uses past values of the input and the ouput - something like
y(k) ~ f(y(k-1),y(k-2),u(k),u(k-1) ....) (k is time index). As far as I
know I could use earth(MARS), nnet and etc but I am not sure how to deal
with the past values since most, if not all, examples I saw formula does not
take in account past
2011 Jul 13
3
Rcompression on MAC - where is it?
Hello
I need to run an r-file that works on Windows on MAC. The first lines of the file are:
library(R.matlab)
library(Rcompression)
Somehow I cannot find where Rcompression is. Am I missing something?
Many thanks
Ed
2007 Oct 15
1
String concatenation, File Path Handling to pass to download.file( ) [backslash in DOS paths]
Gabor,
Thanks much. Your solution is elegant. My overall scheme is to take
present date, and check whether it is a weekend, if not, then create a
string based on the date, to concatenate into a url link for
download.file( ). The files I need to download have a part which is in
the format: mmddyy. I am working to make myself a system to connect to
exchanges, and download end of day files from
2011 Sep 02
2
How to keep the same class?
Hello
Please see the example below
> class(testX)
[1] "matrix"
> class(testX[1,])
[1] "numeric"
Why not matrix? What am I missing here? Is there a way to keep the same
class?
The reason for the question is that I want to implement a k-step ahead
prediction for my own routines and R wrecks does not seem to like [1,] as
shown below.
>
2011 Aug 18
2
Concatenate two strings in one in a string matrix
Dear R-Users
I have the following matrix
> out$desc [,1] [,2]
[1,] "" ""
[2,] "y_{01}(k-001)" ""
[3,] "y_{01}(k-002)" ""
[4,] "y_{01}(k-003)" ""
[5,] "u_{01}(k-001)" ""
[6,] "u_{01}(k-002)" ""
[7,] "u_{01}(k-003)" ""
2008 Aug 29
2
Newbie: Examples on functions callling a library etc.
Hello
R is pretty new to me. I need to write a function that returns three
matrices of different dimensions. In addition, I need to call a function
from a contributed package with the function. I have browsed several
manuals and docs but the examples on them are either very simple or
extremely hard to follow.
Many thanks
Ed
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2011 Jul 26
2
How to use as.Date (or something else) with "31-Jul-2010 23:59:00"
Hello
I have a huge file (not an R-file) in which the first column is a string
with date, hour, minutes and seconds (For instance, "31-Jul-2010 23:59:00").
I tried as.Date but the error msg was "Error in charToDate(x) :
character string is not in a standard unambiguous format".
I have checked the help for the function as well as date but to no avail.
How can that sort
2014 Jul 25
1
R-3.1.1 - R CMD INSTALL problem
Hello
I have recently upgraded R to the newest version. Unfortunately my old (fortran and C) R-package cannot be installed anymore (was built before R 3.0.0: please re-install it).
I have tried R CMD INSTALL package_name but I noticed that R-3.1.1-binary-mac requests gcc-4.8.2 and specific locations for the libraries (gcc and gfortran). Can someone point me to the documentation on how to
2011 Jul 30
1
Plot.xts - how to change the x-axis labels to show weekly labels.
Dear R-users
I am new to R and struggling not to bother the list with silly questions.
I read the documentation on xts and searched for some examples over the
internet on how to use plot.xts.
The xts object is as follows
dataxts : An 'xts' object from 2010-06-27 to 2010-08-05 containing:
Data: num [1:56161, 1:14] 74 74.2 74.2 74.1 73.9 ...
Indexed by objects of
2010 May 08
1
matrix cross product in R different from cross product in Matlab
Hi all,
I have been searching all sorts of documentation, reference cards, cheat
sheets but can't find why R's
crossprod(A, B) which is identical to A%*%B
does not produce the same as Matlabs
cross(A, B)
Supposedly both calculate the cross product, and say so, or where do I
go wrong?
R is only doing sums in the crossprod however, as indicated by
(z <- crossprod(1:4)) # = sum(1 +
2008 Jun 08
20
how to parse a "dd/mm/yyyy" formatted date string???
Hi,
I''m stuck. How do you parse a "dd/mm/yyyy" formatted date string???
I get a date format error.
Thanks in advance
Greg
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2011 Nov 08
1
Building package problem
Dear R-users
I am trying to recompile a CRAN package on Windows 32. Rtools for 2.14 (that is the version I am running) and miktex were sucessfully installed on my machine.
Problems:
a) hydroGOF is a CRAN package, but R CMD check does not work on it.
C:\Users\eduardo\Documents\R_tests2>R CMD check hydroGOF
* using log directory 'C:/Users/eduardo/Documents/R_tests2/hydroGOF.Rcheck'
2007 Jul 16
1
R equivalent to Matlab's Bayes net toolbox
Hi,
I'm attending summer School at UCLA (IPAM) on "probabilistics models of
cognition". I have been an R-user since v. 1.4.1, but was trained in the
frequentist tradition (as most psychologists!). I found that all faculty
here use matlab and Murphy's bayes net toolbox. I have not had the need to
use matlab before, and would love to stick to R for graphics models and
2007 Jun 26
4
Looking for parallel functionality between Matlab and R
I'm slowly moving my statistical analysis from Matlab to R, and find myself
missing two features:
a) How do I mimic Matlab's 'hold on'? (I want to show several plots
together, when I type two plots one after the other the second overwrites
the first)
b) How do I mimic Matlab's 'axis'? (after drawing my plots I want to zoom on
specific parts- for example, x=0:5,
2009 Jan 30
3
Matlab inv() and R solve() differences
I submit the following matrix to both MATLAB and R
x= 0.133 0.254 -0.214 0.116
0.254 0.623 -0.674 0.139
-0.214 -0.674 0.910 0.011
0.116 0.139 0.011 0.180
MATLAB's inv(x) provides the following
137.21 -50.68 -4.70 -46.42
-120.71 27.28 -8.94 62.19
-58.15 6.93 -7.89 36.94
8.35 11.17 10.42 -14.82
R's solve(x) provides:
261.94 116.22 150.92 -267.78
116.22 344.30 286.68
2005 Oct 18
6
p-value calculation
hello everybody
i'm very new at using R so probably this is a very stupid question.
I have a problem calculating a p-value. When i do this with excel i
can use the method CHIDIST for 1.2654 with 1 freedom degree i get the
answer 0.261
i just want to do the same thing in R but i can't find a method.
can somebody help me
friendly regards
richard
2008 Oct 01
3
How to get the day of the year
Hello,
I am new to R and I would like to get the day of the year from numerous data in the following form: %a %d/%b/%Y %H:%M:%S (for example from Tu 10/Jul/2007 21:59:13 I would like to get 191)
Whatever I try, I get NAs.
Well... I need your help, please!
Thanks in advance
Yours sincerely,
Solène Goy
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