On Jun 14, 2012, at 3:20 AM, Rui Barradas wrote:
Hello,
Now the output of str() says 'dat' is a list not a data.frame.
That's why R is complaining about dimensions (lack of, in this case).
Try
dat2 <- data.frame(do.call(cbind, dat), stringsAsFactors=FALSE)
The construction data.frame(cbind(.)) should be severely deprecated.
It coerces all the columns to be of the same class and removes all
the attributes except names. This is what happens to a POSIXlt "vector":
data.frame(do.call(cbind, list(a=1:10, b=as.POSIXlt(ISOdate(2001,
1:10, 1))) ),stringsAsFactors=FALSE )
a b
1 1 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
2 2 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
3 3 12, 12, 12, 12, 12, 12, 12, 12, 12, 12
4 4 1, 1, 1, 1, 1, 1, 1, 1, 1, 1
5 5 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
6 6 101, 101, 101, 101, 101, 101, 101, 101, 101, 101
7 7 1, 4, 4, 0, 2, 5, 0, 3, 6, 1
8 8 0, 31, 59, 90, 120, 151, 181, 212, 243, 273
9 9 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
10 10 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
Use instead:
dat2 <- data.frame( dat, stringsAsFactors=FALSE)
The data.frame function will do the cbinding actions but will preserve
column attributes such as POSIXlt. The process may convert to POSIXct
from POSIXlt.
> structure(data.frame(list(a=1:10, b=as.POSIXlt(ISOdate(2001, 1:10,
1)))) )
a b
1 1 2001-01-01 12:00:00
2 2 2001-02-01 12:00:00
3 3 2001-03-01 12:00:00
4 4 2001-04-01 12:00:00
5 5 2001-05-01 12:00:00
6 6 2001-06-01 12:00:00
7 7 2001-07-01 12:00:00
8 8 2001-08-01 12:00:00
9 9 2001-09-01 12:00:00
10 10 2001-10-01 12:00:00
> str(data.frame(list(a=1:10, b=as.POSIXlt(ISOdate(2001, 1:10, 1)))) )
'data.frame': 10 obs. of 2 variables:
$ a: int 1 2 3 4 5 6 7 8 9 10
$ b: POSIXct, format: "2001-01-01 12:00:00" "2001-02-01 12:00:00"
"2001-03-01 12:00:00" ...
--
David.
Then run the lapply()
Also, if dput(head(dat, 20)) is very big, ommit the argument 20.
See ?head for its meaning.
But if the above works there's no need for it.
Rui Barradas
Em 14-06-2012 01:06, capital_P escreveu:
Rui Barradas wrote
Sorry, but the output of dput() starts with 'structure', not like
what
you've posted.
And there are much more than 20 dates in the beginning.
The posting guide is easy to find
apologies for my earlier ignorance.
It seems the output of dput(head(data, 20) is too big to print in
full. When
I press stop immediately after pressing enter, I get:
dput(head(long, 30))
structure(list(tripID = c(3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L,
3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L,
3L, 3L, 3L, 3L, 3L), device_info_serial = c(121L, 121L, 121L,
121L, 121L, 121L, 121L, 121L, 121L, 121L, 121L, 121L, 121L, 121L,
121L, 121L, 121L, 121L, 121L, 121L, 121L, 121L, 121L, 121L, 121L,
121L, 121L, 121L, 121L, 121L), mdate = structure(c(33L, 33L,
33L, 33L, 33L, 33L, 33L, 33L, 33L, 33L, 33L, 33L, 33L, 33L, 33L,
If I let it run just a little bit longer, it gives the enormous
output like
before.
I made a new vector containing only the columns I need for this
problem:
str(dat)
List of 4
$ device_info_serial: int [1:34773] 121 121 121 121 121 121 121
121 121 121
...
$ hour : int [1:34773] 10 11 11 11 11 11 11 11 11
11 ...
$ time : POSIXlt[1:34773], format: "2009-05-21
10:59:24" ...
$ tripID : int [1:34773] 3 3 3 3 3 3 3 3 3 3 ...
You were right about the factors. I think I solved it using:
dat$time<- strptime(long$date_time.x, format = "%Y-%m-%d %H:%M:%S")
this seems to help, as R doesn't start computing for hours. It does
give an
error though:
departures<- lapply(split(dat, list(dat$device_info_serial, dat
$tripID)),
function(x) x[x$time == min(x$time),])
Error in x[x$time == min(x$time), ] : incorrect number of dimensions
In addition: Warning messages:
1: In split.default(dat, list(dat$device_info_serial, dat$tripID)) :
data length is not a multiple of split variable
2: In min(x$time) : no non-missing arguments to min; returning Inf
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______________________________________________
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
David Winsemius, MD
West Hartford, CT
______________________________________________
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
