Displaying 20 results from an estimated 10000 matches similar to: "finding the year of a date"
2010 Aug 13
3
transforming dates into years
Hello!
If I have in my data frame MyFrame a variable saved as a Date and want
to translate it into years, I currently do it like this using "zoo":
library(zoo)
as.year <- function(x) as.numeric(floor(as.yearmon(x)))
myFrame$year<-as.year(myFrame$date)
Is there a function that would do it directly - like "as.yearmon" -
but for years?
Thank you!
-- 
Dimitri
2011 May 19
1
Creating a "shifted" month (one that starts not on the first of each month but on another date)
Hello!
I have a data frame with dates. I need to create a new "month" that
starts on the 20th of each month - because I'll need to aggregate my
data later by that "shifted" month.
I wrote the code below and it works. However, I was wondering if there
is some ready-made function in some package - that makes it
easier/more elegant?
Thanks a lot!
# Example data:
2011 May 06
1
Extracting months and years from Dates while keeping order
Hello!
I'd like to take Dates and extract from them months and years - but so
that it sorts correctly. For example:
x1<-seq(as.Date("2009-01-01"), length = 14, by = "month")
(x1)
order(x1)  # produces correct order based on full dates
# Of course, I could do "format" - but this way I am losing the "Date"
quality of the data:
2011 Feb 25
6
preventing repeat in "paste"
Hello!
s<-"start"; e<-"end"
middle<-as.character(c(1,2,3))
I would like to get the following result:
"start 123 end" or "start 1 2 3 end" or "start 1,2,3 end"
How can I avoide this (undesired) result:
paste(s,middle,e,sep=" ")
Thank you!
-- 
Dimitri Liakhovitski
Ninah Consulting
www.ninah.com
2011 Apr 04
2
merging 2 frames while keeping all the entries from the "reference" frame
Hello!
I have my data frame "mydata" (below) and data frame "reference" -
that contains all the dates I would like to be present in the final
data frame.
I am trying to merge them so that the the result data frame contains
all 8 dates in both subgroups (i.e., Group1 should have 8 rows and
Group2 too). But when I merge it it's not coming out this way. Any
hint would be
2017 Oct 06
2
Time series: xts/zoo object at annual (yearly) frequency
Hi,
   I'd like to make a time series at an annual frequency.
> a<-xts(x=c(2,4,5), order.by=c("1991","1992","1993"))
Error in xts(x = c(2, 4, 5), order.by = c("1991", "1992", "1993")) :
  order.by requires an appropriate time-based object
> a<-xts(x=c(2,4,5), order.by=1991:1993)
Error in xts(x = c(2, 4, 5), order.by =
2010 Oct 01
3
Suppressing printing in the function
Hello!
I wrote a function that returns a data frame. Nowhere in the function
do I say print(my.data.frame), but when I run the function - the data
frame is printed on the console.
Is there any way to suppress it?
Thank you!
-- 
Dimitri Liakhovitski
Ninah Consulting
www.ninah.com
2011 May 23
1
weird problem - R is not finding the data for the factor level present in the data
Sorry for no code - but it's a more of a general question.
I have read in a data frame ("|"-delimited, .txt).
daily<-read.table(file="filename.txt",sep="|",header=T)
One of the variables is a factor with 110 levels:
>str(daily$dma_id)
 Factor w/ 110 levels "500","501","503",...
108 levels of this factor happen to be numbers
2011 Mar 30
3
optim and optimize are not finding the right parameter
Dear all,
I have a function that predicts DV based on one predictor pred:
pred<-c(0,3000000,7800000,15600000,23400000,131200000)
DV<-c(0,500,1000,1400,1700,1900)
## I define Function 1 that computes the predicted value based on pred
values and parameters a and b:
calc_DV_pred <- function(a,b) {
 DV_pred <- rep(0,(length(pred)))
 for(i in 1:length(DV_pred)){
   DV_pred[i] <- a *
2009 Oct 13
4
replacing period with a space
Dear R-ers!
I have x as a variable in a data frame x.
x<-data.frame(x=c("aa.bb","cc.dd.ee"))
x$x<-as.character(x$x)
x
I am sorry for such a simple question - but how can I replace all
periods in x$x with spaces?
sub('.', ' ', x$x) - removes all letters to the left of each period...
Thanks a lot for your advice!
-- 
Dimitri Liakhovitski
Ninah.com
2010 Mar 04
4
Analogue to SPSS regression commands ENTER and REMOVE in R?
I am not sure if this question has been asked before - but is there a
procedure in R (in lm or glm?) that is equivalent to ENTER and REMOVE
regression commands in SPSS?
Thanks a lot!
-- 
Dimitri Liakhovitski
Ninah.com
Dimitri.Liakhovitski at ninah.com
2009 Sep 23
2
Function to check if a vector contains a given value?
Dear R'rs,
is there a function that checks if a given vector contains a certain value.
E.g., x<-c(1,2,3,4).
How can I get a TRUE or FALSE for whether x contains a 2?
-- 
Dimitri Liakhovitski
Ninah.com
Dimitri.Liakhovitski at ninah.com
2010 Mar 18
1
R takes long time to open
Hello.
Until today I've been using R2.9 and since today R2.10 (on a PC).
In both of them it takes about 20 sec for the prompt to appear IN R
console after I start R. And every time it says: "Previous saved work
space restored" - even if I have not saved any workspace or, in case
of R2.10 - even though I have not used it once.
In the older versions - R would start within 2-3 sec.
Is
2011 Feb 24
4
Running code sequentially from separate scripts (but not functions)
Hello!
I am wondering if it's possible to run - in sequence - code that is
stored in several R scripts.
For example:
Script in the file "code1.r" contains the code:
a = 3; b = 5; c = a + b
Script in the file "code2.r" contains the code:
d = 10; e = d - c
Script in the file "code3.r" contains the code:
result=e/a
I understand that I could write those 3 scripts
2010 Mar 09
2
looping through predictors
Dear R-ers,
I have a data frame data with predictors x1 through x5 and the
response variable y.
I am running a simple regression:
reg<-lm(y~x1, data=data)
I would like to loop through all predictors. Something like:
predictors<-c("x1","x2",... "x10)
for(i in predictors){
  reg<-lm(y~i)
 etc.
}
But it's not working. I am getting an error:
Error in
2010 Aug 04
6
applying strsplit to a whole column
I am sorry, I'd like to split my column ("names") such that all the
beginning of a string ("X..") is gone and only the rest of the text is
left.
x<-data.frame(names=c("X..aba","X..abb","X..abc","X..abd"))
x$names<-as.character(x$names)
(x)
str(x)
Can't figure out how to apply strsplit in this situation - without
using a
2010 Mar 30
4
Code is too slow: mean-centering variables in a data frame by subgroup
Dear R-ers,
I have  a large data frame (several thousands of rows and about 2.5
thousand columns). One variable ("group") is a grouping variable with
over 30 levels. And I have a lot of NAs.
For each variable, I need to divide each value by variable mean - by
subgroup. I have the code but it's way too slow - takes me about 1.5
hours.
Below is a data example and my code that is too
2011 Feb 03
1
rgenoud for multiple chips: does a more recent special version of "snow" exist?
Dear everyone,
I am trying to run rgenoud on several chips simultaneusly. I used the
instructions provided on Jasjeet Sekhon's Homepage
(http://sekhon.berkeley.edu/rgenoud/multiple_cpus.html).
However, I have the newer version of R (R 2.12) installed - for a
64-bit machine. So, when I tried to install the special version of
"snow" from a zip file provided by Jasjeet on his page, R
2010 Oct 29
1
help pages do not open
I have just installed R 12.
I have Windows 7, 64-bit verison.
I currently have IE as my default browser. The internet connection is very good.
Whenever I try to run a help command (?lm, for example), I get this error:
Error in shell.exec(url) : access to
'http://127.0.0.1:20271/library/stats/html/lm.html' denied
I first got this message when Google Chrome was my default browser.
For some
2010 Nov 03
2
biding rows while merging at the same time
Hello!
I have 2 data frames like this (well, actually, I have 200 of them):
df1<-data.frame(location=c("loc 1","loc 2","loc
3"),date=c("1/1/2010","1/1/2010","1/1/2010"), a=1:3,b=11:13,c=111:113)
df2<-data.frame(location=c("loc 1","loc 2","loc