[R] date time problem

[Alemu Tadesse]

Dear R users

I am puzzled by the following result from R script. I am trying to convert
local time to UTC time. Time zone is -5, therefore I used the following
approach.

Below is the script.
> Corrected_SA_data$date_time[k-1]
[1] "2007-03-11 01:00:00"
> Corrected_SA_data$TZ[k-1]
[1] -5
> Corrected_SA_data$date_time[k-1]-Corrected_SA_data$TZ[k-1]*3600
[1] "2007-03-11 07:00:00 MDT"

I was expecting this last value to be something like "2007-03-11 06:00:00
UTC"

Please correct me if I ma wrong.

On the other hand I have
> Corrected_SA_data$date_time[k]
[1] "2007-03-11 02:00:00"
> Corrected_SA_data$TZ[k]
[1] -5
> Corrected_SA_data$date_time[k]-Corrected_SA_data$TZ[k]*3600
[1] NA

I am not sure why I am getting NA.

Thank you for your help.

Alemu

	[[alternative HTML version deleted]]