[R] create zoo object within a for loop

[Wiebke Ullmann]

Dear everyone.

I have a data frame with relocation data of several animals

>head(data)



 
  
                            timestamp
  
  
  individual
  
  
  easting
  
  
  northing
  
 
 
  
  25.03.2014
  07:00
  
  
  animal1
  
  
  410712.5
  
  
  5913542
  
 
 
  
  25.03.2014
  08:00
  
  
  animal1
  
  
  410716.8
  
  
  5913536
  
 
 
  
  25.03.2014
  12:00
  
  
  animal1
  
  
  410717.9
  
  
  5913538
  
 
 
  
  25.03.2014
  17:00
  
  
  animal1
  
  
  410814.2
  
  
  5913827
  
 
 
  
  25.03.2014
  18:00
  
  
  animal1
  
  
  410577.2
  
  
  5912917
  
 
 
  
  25.03.2014
  19:00
  
  
  animal1
  
  
  410188.2
  
  
  5913556
  
 
 
  
  25.03.2014
  20:00
  
  
  animal1
  
  
  410413.8
  
  
  5913581
  
 
 
  
  25.03.2014
  21:00
  
  
  animal1
  
  
  409929.5
  
  
  5913376
  
 
 
  
  25.03.2014
  22:00
  
  
  animal1
  
  
  410007.5
  
  
  5913425
  
 
 
  
  25.03.2014
  07:00
  
  
  animal2
  
  
  410712.5
  
  
  5913542
  
 
 
  
  25.03.2014
  08:00
  
  
  animal2
  
  
  410716.8
  
  
  5913536
  
 
 
  
  25.03.2014
  12:00
  
  
  animal2
  
  
  410717.9
  
  
  5913538
  
 
 
  
  25.03.2014
  17:00
  
  
  animal2
  
  
  410814.2
  
  
  5913827
  
 
 
  
  25.03.2014
  18:00
  
  
  animal2
  
  
  410577.2
  
  
  5912917
  
 
 
  
  25.03.2014
  19:00
  
  
  animal2
  
  
  410188.2
  
  
  5913556
  
 
 
  
  25.03.2014
  20:00
  
  
  animal2
  
  
  410413.8
  
  
  5913581
  
 
 
  
  25.03.2014
  21:00
  
  
  animal2
  
  
  409929.5
  
  
  5913376
  
 
 
  
  25.03.2014
  22:00
  
  
  animal2
  
  
  410007.5
  
  
  5913425
  
 
 
  
  26.03.2014
  08:00
  
  
  animal3
  
  
  410546.3
  
  
  5913590
  
 
 
  
  26.03.2014
  09:00
  
  
  animal3
  
  
  410668.3
  
  
  5913467
  
 
 
  
  26.03.2014
  10:00
  
  
  animal3
  
  
  410665.3
  
  
  5913556
  
 
 
  
  26.03.2014
  11:00
  
  
  animal3
  
  
  410652.9
  
  
  5913450
  
 
 
  
  26.03.2014
  12:00
  
  
  animal3
  
  
  410649.4
  
  
  5913464
  
 



Some  hours in the timestamp are missing. I would like to fill the timestamp with the missing hours and the other variables with the last occuring information. It should look like this:




 
  
  timestamp
  
  
  individual
  
  
  easting
  
  
  northing
  
 
 
  
  25.03.2014
  07:00
  
  
  animal1
  
  
  410712.5
  
  
  5913542
  
 
 
  
  25.03.2014
  08:00
  
  
  animal1
  
  
  410716.8
  
  
  5913536
  
 
 
  
  25.03.2014
  09:00
  
  
  animal1
  
  
  410716.8
  
  
  5913536
  
 
 
  
  25.03.2014
  10:00
  
  
  animal1
  
  
  410716.8
  
  
  5913536
  
 
 
  
  25.03.2014
  11:00
  
  
  animal1
  
  
  410716.8
  
  
  5913536
  
 
 
  
  25.03.2014
  12:00
  
  
  animal1
  
  
  410717.9
  
  
  5913538
  
 


 ...


I know how to do this with a data frame that only includes the information of one animal. I used an index in zoo:

>animal1$time <- strptime(animal1$timestamp, format="%Y-%m-%d %H:%M:%S")
>animal1$time <- as.POSIXct(format(round(animal1$time, units="hours"), 
                                         format="%Y-%m-%d %H:%M"))
>animal1.zoo  <- zoo(animal1[,-5],animal1[,5]) #set Index
>animal1m     <- merge(animal1.zoo,
                       zoo(,seq(animal1[1,5],animal1[length(animal1$timestamp),5],by="hour")), 
                           all=TRUE)

And filled the other variables with na.locf.

But I do not know how to do this in one go for all the animals. I would like to use a for loop or lappy for lists.
I would be very glad if you could help me out. Thank you very much in advance.

Cheers,
Vivi
 		 	   		  
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