Try something similar to this: ## unchanged full <- read.table("March_15.dat", sep=",",row.names=NULL, as.is=TRUE,skip=1,header=TRUE)
## then convert TIMESTAMP to a date-time class full$TIMESTAMP <- as.POSIXct(full$TIMESTAMP) ## now you can use subset() atimeframe <- subset(full, TIMESTAMP >= as.POSIXct('2011-03-15 00:00:00') & TIMESTAMP <= as.POSIXct('2011-03-15 00:01:30') ) Hope this helps. And a couple of comments on your example. In an expression like you used, timestamp==as.character("2011-03-15 00:01:30") just do timestamp=="2011-03-15 00:01:30" "2011-03-15 00:01:30" is already a character string, so you don't have to use as.character() on it. You used for(), but for() is used to make loops, as in for (i in 1:10) { } which has basically nothing to do with extracting a subset of rows from a dataframe. -Don -- Don MacQueen Lawrence Livermore National Laboratory 7000 East Ave., L-627 Livermore, CA 94550 925-423-1062 -----Original Message----- From: Pablo Rosado <pablojros...@lbl.gov> Date: Wed, 11 May 2011 14:21:00 -0700 To: "r-help@r-project.org" <r-help@r-project.org> Subject: [R] selecting data from table with timestamp >Hi, >I am using read.table to get this data that has a timestamp. The data is >for many days, but I only want to run the code I wrote only for specific >day/days/times. I canĀ“t figure out how to select a timeframe from the >list. >I have tried using subset() and didn't work > >I then used: >* timestamp[for(timestamp==as.character("2011-03-15 00:00:00" ) | >timestamp==as.character("2011-03-15 00:01:30"))]* >but it gives me the list of the timestamp for that interval, but I want >the >complete data.table for that interval, not just the values of the >TIMESTAMP >column. > >Here is the script I use to read the table and select the timestamp >interval: > >*full <- read.table("March_15.dat", sep=",",row.names=NULL, >as.is=TRUE,skip=1, >header=TRUE) >minusrows <- full[-1:-2,] >names(minusrows) >timestamp <- minusrows[,1] >timestamp3 <- timestamp[for(timestamp==as.character("2011-03-15 00:00:00" >) >| timestamp==as.character("2011-03-15 00:01:30"))] >timestamp3* > >An example of what minusrows look like: >* >> minusrows[1:5,1:4] > TIMESTAMP RECORD Batt_Volt_Avg attic.air_temp_cool_north >3 2011-03-15 00:00:00 0 13.35 17.99 >4 2011-03-15 00:00:30 1 13.35 18.00 >5 2011-03-15 00:01:00 2 13.35 17.98 >6 2011-03-15 00:01:30 3 13.35 17.99 >7 2011-03-15 00:02:00 4 13.35 17.97* > >Thank You so much for your help and time, > > >-- >*Pablo J. Rosado*, *Ph.D. Student* >*Graduate Student Researcher Assistant* >*University of California - Berkeley* > > [[alternative HTML version deleted]] > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.