[R] Convert to date and time of the year

[Ben Tupper]

Hi Janesh,

On Mar 18, 2013, at 10:49 PM, Janesh Devkota wrote:

> Dear R Users, 
> 
> I have data for more than 3 years. For each year I want to find the day
> corresponding to Jaunary 1 of that year. For example:
> 
>> x <- c('5/5/2007','12/31/2007','1/2/2008')
> 
>> #Convert to day of year (julian date) -
> 
>> strptime(x,"%m/%d/%Y")$yday+1
> 
> [1] 125 365   2
> 
> I want to know how to do the same thing but with time added. But I still get
> the day not time. Can anyone suggest what is the better way to find the
> julian date with date and time ?
> 
>> x1 <- c('5/5/2007 02:00','12/31/2007 05:58','1/2/2008 16:25')
> 
>> #Convert to day of year (julian date) -
> 
>> strptime(x1,"%m/%d/%Y %H:%M")$yday+1
> 
> [1] 125 365   2
> 

Would this do it for you?

x1 <- c('5/5/2007 02:00','12/31/2007 05:58','1/2/2008 16:25')
x1 <- as.POSIXct(x1, format = "%m/%d/%Y %H:%M")

day <- as.numeric(format(x1, "%j")) 
hour <- as.numeric(format(x1, "%H"))/24 
minute <- as.numeric(format(x1, "%M"))/(60*24) 
second <- as.numeric(format(x1, "%S"))/(60*60*24)

day + hour + minute + second

[1] 125.083333 365.248611   2.684028

Cheers,
Ben




> Thank you so much.
> 
> Janesh
> 
> 
> 	[[alternative HTML version deleted]]
> 
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Ben Tupper
Bigelow Laboratory for Ocean Sciences
60 Bigelow Drive, P.O. Box 380
East Boothbay, Maine 04544
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