Re: [R] How to extract information from the following dataset?

From: John Kane <jrkrideau_at_yahoo.ca>
Date: Thu, 12 May 2011 04:36:30 -0700 (PDT)


? subset day = x time > y | time < z

> From: hwright <heather.wright_at_maine.edu>
> Subject: Re: [R] How to extract information from the following dataset?
> To: r-help_at_r-project.org
> Received: Thursday, May 12, 2011, 6:18 AM
>
> I have the following data set, in a csv file, looks like
> the following:
>
> Jan 27, 2010  16:01:24,000 125 - - -
> Jan 27, 2010  16:06:24,000 125 - - -
> ......
> The first few columns are month, day, year, time with OS3
> accuracy. And the
> last number is the measurement I need to extract.
> I wonder if there is a easy way to just take out the
> measurements only from
> a specific day and hour
> --
> Xin Zhang
> Ph.D Candidate
> Department of Statistics
> University of California, Riverside
> -------------------------------------------------------------------
>
> I use strptime to configure the date format in my times
> series dataset.
> First check to see how the dates are read.
> For example:
> # check the structure
> str(your_file)
> 'data.frame' ...etc
> This tells me that my original date is a factor but not in
> POSIXlt format.
>
> #check your column dates
> head(your_file)
> [1] "1984-01-26" "1984-02-09" "1984-03-01" "1984-03-15"
> "1984-03-29"
> "1984-04-12"
> These are discrete column dates.
>
> #convert your date format
> your_file$date<- strptime(your_file$date,"%m/%d/%Y")
> call ?strptime for options
>
> Example:
> For a specific day or hour, strptime would utilize:
> strptime(your_file$date,"%d/%I") for day and hour.
>
> Once you extract the type of date format you want, run
> str(your_file) again
> to confirm the format change.
> Does this answer your question?
> Best,
>
>
>
> -----
> -------------------------------
> Heather A. Wright, PhD candidate
> Ecology and Evolution of Plankton
> Stazione Zoologica Anton Dohrn
> Villa Comunale
> 80121 - Napoli, Italy
> --
> View this message in context: http://r.789695.n4.nabble.com/How-to-extract-information-from-the-following-dataset-tp3516752p3516952.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help_at_r-project.org
> mailing list
>
https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained,
> reproducible code.
>



R-help_at_r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Thu 12 May 2011 - 11:41:33 GMT

This quarter's messages: by month, or sorted: [ by date ] [ by thread ] [ by subject ] [ by author ]

All messages

Archive maintained by Robert King, hosted by the discipline of statistics at the University of Newcastle, Australia.
Archive generated by hypermail 2.2.0, at Thu 12 May 2011 - 11:50:06 GMT.

Mailing list information is available at https://stat.ethz.ch/mailman/listinfo/r-help. Please read the posting guide before posting to the list.

list of date sections of archive