Displaying 20 results from an estimated 6000 matches similar to: "Time and db precision"
2012 Mar 06
3
Label rows of table by factor level for groups of factors
Dear useRs,
I am sure this is a fairly simple problem, but I just cannot get my head around it.
I have a dataframe which contains several factor variables. I can use table() to tell me how many different combinations there are of these variables. What I should like to do is to add a column to my original dataframe which labels each row according to the unique combination of factors.
E.g. in
2006 Jan 27
3
substituting an object not found
Is there any function in R like
is.not.found(x, y)
meaning if you can't find object x, then use object
y??
Mikkel Grum
2010 Dec 28
4
batch file output
I run a batch file with the following command in Windows XP:
C:\R\R-2.12.1\bin\Rterm.exe --no-save --no-restore <C:\users\me\file.R> C:\users\me\file.out 2>&1
Is there any way to get only the output of R in file.out, without getting all the code from file.R too?
Any help greatly appreciated,
Mikkel
2007 Dec 30
3
Date formats
Is the following expected behaviour for a date used in
an ifelse function?
> date <- Sys.Date()
> date
[1] "2007-12-30"
> ifelse(TRUE, date-1, date)
[1] 13876
> ifelse(FALSE, date-1, date)
[1] 13877
> ifelse(TRUE, as.character(date-1), date)
[1] "2007-12-29"
> if (TRUE) {date}
[1] "2007-12-30"
It would seem more natural to me if a date produced
2011 May 02
2
INSERT OR UPDATE
I'm trying to insert rows of a data.frame into a database table, or update where the key fields of a record already exist in the table. I've come up with a possible solution below, but would like to hear if anyone has a better solution.
# The problem demonstrated:
# Create a data.frame with test values
library(RODBC)
tbl <- data.frame(
key1 = rep(1:3, each = 2),
key2 =
2004 Dec 31
2
Supressing empty sections with Sweave
Dear useRs,
I'm writing regular survey reports using Sweave. Each
report has several sections along the lines of:
\section*{Disease X}
<<MapX,fig=TRUE,echo=FALSE>>=
image(vectorx,vectory,matrixz)
@
Notes with or without Sexpr{a}.
\vfill
\pagebreak
\section*{Disease Y}
<<MapY,fig=TRUE,echo=FALSE>>=
...etc.
Often one or more of the diseases is not observed (all
2007 Aug 07
2
backslash c
How do I get output with "\color{blue}", i.e. with
only one backslash???
> "\color{blue}"
[1] "color{blue}"
Warning messages:
1: '\c' is an unrecognized escape in a character
string
2: unrecognized escape removed from "\color{blue}"
> "\\color{blue}"
[1] "\\color{blue}"
>
Any help greatly appreciated.
Best regards,
2005 Jun 01
3
x[x$a=="q",,drop=TRUE]
I'm trying to select a subset of a dataframe while
dropping some factors. While the dataset gets smaller
all Factor levels remain and I need to get rid of
them. Strangely enough, I am almost certain that the
same code on the same data worked OK earlier today -
and it is not the first time that I'm not able to
replicate earlier results with this command (I know, I
might just be going
2006 Jan 02
1
"7:9, 12:14" in dataframe to c(7:9, 12:14)
I want to do something like df[df$b %in% df2[i, 2], ]
where df$b is a numeric vector and df2[i, 2] is a
factor with
levels like "7:9, 12:14". For example:
a <- c(paste("A", 1:10, sep = ""), paste("B", 1:10,
sep = ""))
b <- 1:20
df <- as.data.frame(cbind(a, b))
df$b <- as.numeric(levels(df$b))[as.integer(df$b)]
f <-
2004 Sep 01
2
RODBC query on one line
Dear R-helpers,
When I use sqlQuery in the package RODBC, I cannot
break the line, but have to write the entire SQL Query
on the same line. Is this expected behaviour? It is
definitely workable, but makes the queries a slightly
difficult to read and edit.
I'm using R 1.9.1 and RODBC 1.0-4 on Windows Server
2003 and querying a Sybase database.
Best wishes,
Mikkel
2007 Nov 24
2
truncated fields with RODBC
I'm changing some functions from storing data in
SQLite (using RSQLite) to storing it in PostgreSQL
(using RODBC). When trying to store very long
character fields I get the following message:
> sqlSave(pg, Grids, rownames = FALSE, append =
TRUE)
Warning messages:
1: In odbcUpdate(channel, query, mydata, paramdata,
test = test, verbose = verbose, :
character data truncated in column
2004 Dec 21
1
scheduling R tasks under windows
I'm trying to schedule R tasks in Windows Server 2003.
I can run the following from the DOS prompt without
any difficulty:
c:\Reports>c:\r\rw2001\bin\rterm.exe --no-restore
--no-save <test.R> test.out
where test.r has two lines: library(tools);
Sweave("rlr.Rnw").
When I try to run the same from the task scheduler, I
fill in the dialogue box as follows:
Run:
2002 Jan 08
6
Subsets without NA
Is there a way of removing all rows with missing values from a data frame?
I usually use
subset(x, var1!="NA")
and repeat for each variable. It would be nice to be able to do it in one
fell swoop. Also, surprisingly, it doesn't always work. Sometimes I'm left
with an empty set even though not all rows have missing values for the
variable.
Cheers,
mikkel
Mikkel Grum,
2010 May 19
1
Pausing calculations for a fixed amount of time
Is there any way to pause R for a gvien time period, i.e. without the
need for user intervention? I've got a loop that I want to have work
as hard as it can as long as there is data coming in, but when there
is no new data, I would like it to pause before checking again.
Something like in the following construction:
Set up environment: load libraries, establish database connections, etc.
2001 Aug 13
3
subset syntax
Can anyone tell me what's wrong with this command??
xx<-subset(x,LOCAL.NAME==c("Chifumbata","Chikota"),select=c(13,16,19,23,26,2
9,30,33:48))
Warning message:
longer object length
is not a multiple of shorter object length in: LOCAL.NAME ==
c("Chifumbata", "Chikota")
both of the following commands work fine
2001 Aug 21
4
looking for a smarter way
I have two problems where I've come up with some code that will do the
analysis that I want, but it looks pretty clumsy. In the first case, I
calculate the variance on five different columns for each of 14 clusters and
get them into one matrix. I get the job done, but I would have thought that
it could be done in one or two lines, not six, and be generalized so that it
didn't matter how
2003 Jan 07
2
Extracting means for given strata from dissimilarity object
Is there a way of extracting mean distance or dissimilarity for a given
strata from a 'dist' or 'dissimilarity' object, e.g. extract mean distances
for each species in Anderson's iris data?
data(iris)
iris.dist<-dist(iris[,1:4])
then what?
Mikkel Grum, PhD
Genetic Diversity Scientist
International Plant Genetic Resources Institute (IPGRI)
Sub-Saharan Africa Group
***
2002 Jan 08
3
colour coding and different point types in a plot
I'm trying to plot four different sorghum types on a plot using a different
colour/symbol combination for each sorghum type (TYPBOTA in the script
below). What am I doing wrong?:
plot(xx$LATITUDE,xx$SFD1,
points(xx$SFD1,xx$LATITUDE,
col=1:4[codes(xx$TYPBOTA)],pch=c(4,3,1,2)[codes(xx$TYPBOTA)])
grid()
I get the following error message
Error in 1:4[codes(xx$TYPBOTA)] : NA/NaN argument
2004 Aug 22
1
latitude longitude data
Dear R-helpers,
I get GPS readings with bug counts (bugs meaning
insects in this case) made along rows in crop fields
and use these to make maps of bug distribution. The
GPS readings are not quite accurate enough for my
purpose, so since I know what row each reading is made
in, I adjust the latitudinal coordinate using:
grd<-lm(lat~lon+Row,data)
2017 Nov 14
1
Dates to numeric in for loop
Hi
Can anyone explain why a date becomes numeric when you loop over a series
of dates?
> dt <- Sys.Date()
> dt
[1] "2017-11-14"
> class(dt)
[1] "Date"
> dts <- dt - 1:0
> class(dts)
[1] "Date"
>
> for (i in dts) {
+ print(i)
+ print(class(i))
+ print(as.Date(i, "1970-01-01"))
+ print(class(as.Date(i,