On Sat, 5 Jan 2013, Simonas Kecorius wrote:
Dear R users,
Could you share your knowledge on following problem:
Suppose we have dataframe:
ID TIME Data1 Data2 Data3
........... Data700
1. 2013-01-01 00:00:00 34 53 66
............ 55
2. 2013-01-01 00:00:01 333 4 5
............ 50
3. 2013-01-01 00:00:02 and so on
4. 2013-01-01 00:00:03 and so on
5. 2013-01-01 03:00:45 44 33 4
............. 66
6. 2013-01-01 03:00:46 46 35 7
............. 6
Notice that between ID 4 and ID 5 there is a gap, that instrument was
turned off. It started automatically in 2013-01-01 03:00:45 and continues
till the next turn off.
What I need R to do, is to find these gaps, and insert missing time values
with empty Data lines to have no gaps in time and empty (or NA) values in
data place:
ID TIME Data1 Data2 Data3
........... Data700
1. 2013-01-01 00:00:00 34 53 66
............ 55
2. 2013-01-01 00:00:01 333 4 5
............ 50
3. 2013-01-01 00:00:02 and so on
4. 2013-01-01 00:00:03 and so on
5. 2013-01-01
00:00:04
<- time with empty (or NA) data values inserted
6. 2013-01-01
00:00:05
<- time with empty (or NA) data values inserted
7. 2013-01-01
00:00:06
<- time with empty (or NA) data values inserted
................
and so on, until the time when instrument works again:
2013-01-01 03:00:45 44 33 4
............. 66
2013-01-01 03:00:46 46 35 7
............. 6
You can use zoo time series with POSIXct time stamps (or chron or
timeDate) and then extend to a regular grid. For example:
## regular time grid (by second)
t <- seq(as.POSIXct("2000-01-01 00:00"), by = "1 sec", length = 5)
## zoo series with only part of the time stamps (3rd stamp missing)
z <- zoo(1:4, t[-3])
## extend to full time grid by merging with an empty zoo series
z2 <- merge(zoo( , t), z)
This yields:
2000-01-01 00:00:00 2000-01-01 00:00:01 2000-01-01 00:00:02
1 2 NA
2000-01-01 00:00:03 2000-01-01 00:00:04
3 4
You can also use different strategies for filling these NAs.
See help("merge.zoo", package = "zoo") for another example and the
vignettes in vignette(package = "zoo") for more details.
All your suggestions will be appreciated!
Simonas Kecorius
**
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and provide commented, minimal, self-contained, reproducible code.
