[R] Data handling

[jim holtman]

FYI.

The fractional part is printed as '3204' instead of '3205' since with
POSIXct you only have accuracy to the millisecond for times around
now.

Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.


On Tue, Oct 15, 2013 at 12:45 PM, jim holtman <jholtman at gmail.com> wrote:
> Try this; your time is converted back to a character string if you
> want to show the fractional part.
>
>> x <- read.table(text = "    Date     Time Fraction
> +  06/19/13 22:15:39   0.3205
> +  06/19/13 22:15:44   0.3205
> +  06/19/13 22:15:49   0.3205
> +  06/19/13 22:15:54   0.3205
> +  06/19/13 22:15:59   0.3205
> +  06/19/13 22:16:09   0.3205", as.is = TRUE, header = TRUE)
>>  x$newTime <- as.POSIXct(
> +     paste0(x$Date, ' ', x$Time , '.', substring(x$Fraction, 3))
> +     , format = "%m/%d/%y %H:%M:%OS"
> +     )
>>  x$formatted <- format(x$newTime, format = "%m/%d/%y %H:%M:%OS4")
>>
>>
>>
>> x
>       Date     Time Fraction             newTime              formatted
> 1 06/19/13 22:15:39   0.3205 2013-06-19 22:15:39 06/19/13 22:15:39.3204
> 2 06/19/13 22:15:44   0.3205 2013-06-19 22:15:44 06/19/13 22:15:44.3204
> 3 06/19/13 22:15:49   0.3205 2013-06-19 22:15:49 06/19/13 22:15:49.3204
> 4 06/19/13 22:15:54   0.3205 2013-06-19 22:15:54 06/19/13 22:15:54.3204
> 5 06/19/13 22:15:59   0.3205 2013-06-19 22:15:59 06/19/13 22:15:59.3204
> 6 06/19/13 22:16:09   0.3205 2013-06-19 22:16:09 06/19/13 22:16:09.3204
>>
>
> Jim Holtman
> Data Munger Guru
>
> What is the problem that you are trying to solve?
> Tell me what you want to do, not how you want to do it.
>
>
> On Tue, Oct 15, 2013 at 10:27 AM, Raoni Rodrigues
> <caciquesamurai at gmail.com> wrote:
>> Hello all,
>>
>> I'm having a problem with data handling. My input data is (dput in the
>> after the signature):
>>
>>     Date     Time Fraction
>>  06/19/13 22:15:39   0.3205
>>  06/19/13 22:15:44   0.3205
>>  06/19/13 22:15:49   0.3205
>>  06/19/13 22:15:54   0.3205
>>  06/19/13 22:15:59   0.3205
>>  06/19/13 22:16:09   0.3205
>>
>> Date in format month/day/year, Time in HH:MM:SS and fraction represents the
>> fractions of seconds. I need to have a vector in a format year-month-day
>> hh:mm:ss.0000. Or, in format: format = "%F %H:%M:%OS4", as POSIXct class.
>>
>> I made the the conversion step-by-step to have sure that nothing is missed
>> in the way:
>>
>>> options (digits.sec = 4)
>>> getOption ("digits.sec")
>> [1] 4
>>> teste$Date1 = as.Date (teste$Date, format = "%m/%d/%y")
>>> class (teste$Date1)
>> [1] "Date"
>>> teste$Fraction = sub ("0.", "", teste$Fraction)
>>> teste$TimeC = paste (teste$Time, teste$Fraction, sep = ".")
>>> teste$TimeCC = paste (teste$Date1, teste$TimeC)
>>
>>> head (teste)
>>       Date     Time Fraction      Date1        TimeC                  TimeCC
>> 1 06/19/13 22:15:39     .325 2013-06-19 22:15:39.325 2013-06-19
>> 22:15:39.3205
>> 2 06/19/13 22:15:44     .325 2013-06-19 22:15:44.325 2013-06-19
>> 22:15:44.3205
>> 3 06/19/13 22:15:49     .325 2013-06-19 22:15:49.325 2013-06-19
>> 22:15:49.3205
>> 4 06/19/13 22:15:54     .325 2013-06-19 22:15:54.325 2013-06-19
>> 22:15:54.3205
>> 5 06/19/13 22:15:59     .325 2013-06-19 22:15:59.325 2013-06-19
>> 22:15:59.3205
>> 6 06/19/13 22:16:09     .325 2013-06-19 22:16:09.325 2013-06-19
>> 22:16:09.3205
>>
>> So far so well. The problem is when I tried to convert to POSIXct class. If
>> I use just:
>>
>> teste$TimeCC = format (teste$TimeCC, format = "%F %H:%M:%OS4")
>> teste$TimeCC = as.POSIXct (teste$TimeCC)
>>
>> I lost the fraction of seconds. If I use:
>>
>> teste$TimeCC = as.POSIXct(strptime (teste$TimeCC, format = "%F %H:%M:%OS4"))
>>
>> I lost all information and get just <NA>.
>>
>> Thanks in advanced,
>>
>> --
>> Raoni Rosa Rodrigues
>> Research Associate of Fish Transposition Center CTPeixes
>> Universidade Federal de Minas Gerais - UFMG
>> Brasil
>> rodrigues.raoni at gmail.com
>>
>> dput of input data
>>
>> structure(list(Date = c("06/19/13", "06/19/13", "06/19/13", "06/19/13",
>> "06/19/13", "06/19/13"), Time = c("22:15:39", "22:15:44", "22:15:49",
>> "22:15:54", "22:15:59", "22:16:09"), Fraction = c("0.3205", "0.3205",
>> "0.3205", "0.3205", "0.3205", "0.3205")), .Names = c("Date",
>> "Time", "Fraction"), row.names = c(NA, 6L), class = "data.frame")
>>
>>         [[alternative HTML version deleted]]
>>
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