[R] Adding Time when Blanks

[Rui Barradas]

Hello,

Try the following.


dat <- read.table(text="
      ID        group Start_date Time_of_experiment Time_of_end
1    20209         4    02/02/2009           12:38:00
26   30209         3   03/02/2009           12:40:00      13:32:00
27   31609         4   03/16/2009           11:28:00      12:26:00
28   40609         4   04/06/2009           11:17:00
53   42709         4   04/27/2009           11:15:00       9:30:00
76   51109         3   05/11/2009           11:51:00
101  51809         1  05/18/2009           12:28:00
126  62209         3  06/22/2009           11:31:00
150  71309         4  07/13/2009           12:12:00      13:37:00
173  81009         4  08/10/2009           11:32:00      20:52:00
", header=TRUE, fill=TRUE)
str(dat)

dat$start_time <- with(dat, paste(Start_date, Time_of_experiment))
dat$Start_of_Experiment <-
     as.POSIXct(strptime(dat$start_time, "%m/%d/%Y %H:%M:%S"))

#--- Create End_of_Experiment
idx <- dat$Time_of_end != ''
dat$End_of_Experiment <- dat$Start_of_Experiment + 48*60*60
dat$End_of_Experiment[idx] <-
     as.POSIXct(strptime(paste(dat$Start_date, dat$Time_of_end)[idx], 
"%m/%d/%Y %H:%M:%S"))
dat


Hope this helps,

Rui Barradas
Em 12-10-2012 18:59, Charles Determan Jr escreveu:
> Greetings,
>
> My data set has dates and times that I am working with.  Some of the times
> in Time_of_end are blank.  This is supposed to dictate that the particular
> experiment lasted 48 hours.  I would like to add 48 hours to the start
> Start_of_Experiment for another column as End_of_Experiment including both
> the ones with 48 added and those with early times.  I was thinking
> something with a conditional statement but I can't seem to figure out what
> code to use.  Any insight would be appreciated.  Let me know if there is
> anything else you need.  Thanks for your time.
>
> I have Start_of_Experiment in POSIX format for time calculations from the
> following:
>
> data$Start_of_Experiment=as.POSIXct(strptime(data$start_time, "%m/%d/%Y
> %H:%M:%S"))
>
> Here is a subset of my data.
>
>          ID        group Start_date Time_of_experiment Time_of_end
> 1    20209         4    02/02/2009           12:38:00
> 26   30209         3   03/02/2009           12:40:00      13:32:00
> 27   31609         4   03/16/2009           11:28:00      12:26:00
> 28   40609         4   04/06/2009           11:17:00
> 53   42709         4   04/27/2009           11:15:00       9:30:00
> 76   51109         3   05/11/2009           11:51:00
> 101  51809         1  05/18/2009           12:28:00
> 126  62209         3  06/22/2009           11:31:00
> 150  71309         4  07/13/2009           12:12:00      13:37:00
> 173  81009         4  08/10/2009           11:32:00      20:52:00
>      Start_of_Experiment
> 1   2009-02-02 12:38:00
> 26  2009-03-02 12:40:00
> 27  2009-03-16 11:28:00
> 28  2009-04-06 11:17:00
> 53  2009-04-27 11:15:00
> 76  2009-05-11 11:51:00
> 101 2009-05-18 12:28:00
> 126 2009-06-22 11:31:00
> 150 2009-07-13 12:12:00
> 173 2009-08-10 11:32:00
>
> 	[[alternative HTML version deleted]]
>
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