Hi
I just started using RGui.exe under widnows.
I have a text file containing date arranged in columns and rows, each column
has the same format, each row with different formats. 3 of the columns are
something like this 1/12/2006 3:59:45 PM
I need to calculate the different in seconds between 2 selected periods using
their rows index
My solution:
Read the file in a data frame and collect the columns in concern in a
variable.
data1 <- read.table("C:\\path\\data.txt", header=TRUE)
ts <- paste(data1[[1]], data1[[3]], data1[[7]])
#ts now looks like this
#... "1/12/2006 3:59:45 PM" "1/12/2006 3:59:57 PM" ...
#now convert between character representations and object of classes "POSIXct"
x <- strptime(ts, "%m/%d/%y %I:%M:%S %p")
this last code line is putting out NA, what did I do wrong?
After this then I do
z <- as.POSIXct(x)
Is my whole approach efficient?
Then I can use difftime, because using it without the above preparations
gives this
> difftime(c("1/12/2006 3:59:45 PM", "1/12/2006 3:59:57 PM"), format
="%m/%d/%y %I:%M:%S %p")
Error in difftime(c("1/12/2006 3:59:45 PM", "1/12/2006 3:59:57 PM"), format =
"%m/%d/%y %I:%M:%S %p") :
unused argument(s) (format ...)
Thanks
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