[R] How to format data for time-series analysis
B. Bogart
bbogart at sfu.ca
Mon Oct 29 00:11:57 CET 2007
Hey all again,
So I'm going through tutorials and getting a better sense of R structures.
So I made some mockup data to see if I can figure out how to load it
properly. (attached) if anyone has any suggestions on a better way to
structure that data please let me know.
So the file has three columns, the date/time of the event, the event
name, the event state (if there is one) and the event value (if there is
one). I'm using the built-in date/time class of openoffice as a starting
point for the date/time.
I'm expecting to load this file as a data.frame where each column is a
different class. Like so:
> data <-
read.table(file="testdata.csv",sep=",",header=TRUE,colClasses=c("zoo","factor","factor","numeric"))
Unfortunately It seems there is no function for converting from
"character" to "zoo":
Error in methods::as(data[[i]], colClasses[i]) :
no method or default for coercing "character" to "zoo"
So I tried using POSIXct as suggested.
Which does load the file, but it seems the times are truncated, leaving
only the dates:
> data
Time Event State Value
1 24-10-20 BMU 20
2 25-10-20 Image 2
...3 26-10-20 BMU 10
4 27-10-20 BMU 11
5 28-10-20 Image 3
6 29-10-20 DPMS Begin NA
7 30-10-20 Dream Begin NA
8 31-10-20 BMU 3
9 1-11-20 Image 4
10 2-11-20 BMU 50
11 3-11-20 BMU 20
12 4-11-20 DPMS End NA
13 5-11-20 Dream End NA
Same results as using "Date" as the colClass.
Any advice?
Thanks,
B. Bogart
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