[R] Looping Through DataFrames with Differing Lenghts
Ng Bo Lin
ngbolin91 at gmail.com
Tue Mar 28 16:19:15 CEST 2017
Hi Paul,
The date format that you have supplied to R isn’t exactly right.
Instead of supplying the format “%Y-%m-%d”, it appears that the format of your data adheres to the “%e-%B-%y” format. In this case, %e refers to Day, and takes an integer between (0 - 31), %B refers to the 3 letter abbreviated version of the Month, and %y refers to the Year provided in a “2-integer” format.
Hope this helps!
Thank you.
Regards,
Bo Lin
> On 28 Mar 2017, at 10:12 PM, Paul Bernal <paulbernal07 at gmail.com> wrote:
>
> Dear friends Ng Bo Lin, Mark and Ulrik, thank you all for your kind and valuable replies,
>
> I am trying to reformat a date as follows:
>
> Data<-read.csv("Container.csv")
>
> DataFrame<-data.frame(Data)
>
> DataFrame$TransitDate<-as.Date(DataFrame$TransitDate, "%Y-%m-%d")
>
> #trying to put it in YYYY-MM-DD format
>
> However, when I do this, I get a bunch of NAs for the dates.
>
> I am providing a sample dataset as a reference.
>
> Any help will be greatly appreciated,
>
> Best regards,
>
> Paul
>
> 2017-03-28 8:15 GMT-05:00 Ng Bo Lin <ngbolin91 at gmail.com <mailto:ngbolin91 at gmail.com>>:
> Hi Paul,
>
> Using the example provided by Ulrik, where
>
> > exdf1 <- data.frame(Date = c("1985-10-01", "1985-11-01", "1985-12-01”, "1986-01-01"), Transits = c(NA, NA, NA, NA))
> > exdf2 <- data.frame(Date = c("1985-10-01", "1986-01-01"), Transits = c(15,20)),
>
> You could also try the following function:
>
> for (i in 1:dim(exdf1)[1]){
> if (!exdf1[i, 1] %in% exdf2[, 1]){
> exdf2 <- rbind(exdf2, exdf1[i,])
> }
> }
>
> Basically, what the function does is that it runs through the number of rows in exdf1, and checks if the Date of the exdf1 row already exists in Date column of exdf2. If so, it skips it. Otherwise, it binds the row to df2.
>
> Hope this helps!
>
>
> Side note.: Computational efficiency wise, think Ulrik’s answer is probably better. Presentation wise, his is also much better.
>
> Regards,
> Bo Lin
>
> > On 28 Mar 2017, at 5:22 PM, Ulrik Stervbo <ulrik.stervbo at gmail.com <mailto:ulrik.stervbo at gmail.com>> wrote:
> >
> > Hi Paul,
> >
> > does this do what you want?
> >
> > exdf1 <- data.frame(Date = c("1985-10-01", "1985-11-01", "1985-12-01",
> > "1986-01-01"), Transits = c(NA, NA, NA, NA))
> > exdf2 <- data.frame(Date = c("1985-10-01", "1986-01-01"), Transits = c(15,
> > 20))
> >
> > tmpdf <- subset(exdf1, !Date %in% exdf2$Date)
> >
> > rbind(exdf2, tmpdf)
> >
> > HTH,
> > Ulrik
> >
> > On Tue, 28 Mar 2017 at 10:50 Paul Bernal <paulbernal07 at gmail.com <mailto:paulbernal07 at gmail.com>> wrote:
> >
> > Dear friend Mark,
> >
> > Great suggestion! Thank you for replying.
> >
> > I have two dataframes, dataframe1 and dataframe2.
> >
> > dataframe1 has two columns, one with the dates in YYYY-MM-DD format and the
> > other colum with number of transits (all of which were set to NA values).
> > dataframe1 starts in 1985-10-01 (october 1st 1985) and ends in 2017-03-01
> > (march 1 2017).
> >
> > dataframe2 has the same two columns, one with the dates in YYYY-MM-DD
> > format, and the other column with number of transits. dataframe2 starts
> > have the same start and end dates, however, dataframe2 has missing dates
> > between the start and end dates, so it has fewer observations.
> >
> > dataframe1 has a total of 378 observations and dataframe2 has a total of
> > 362 observations.
> >
> > I would like to come up with a code that could do the following:
> >
> > Get the dates of dataframe1 that are missing in dataframe2 and add them as
> > records to dataframe 2 but with NA values.
> >
> > <dataframe1 <dataframe2
> >
> > Date Transits Date
> > Transits
> > 1985-10-01 NA 1985-10-01 15
> > 1985-11-01 NA 1986-01-01 20
> > 1985-12-01 NA 1986-02-01 5
> > 1986-01-01 NA
> > 1986-02-01 NA
> > 2017-03-01 NA
> >
> > I would like to fill in the missing dates in dataframe2, with NA as value
> > for the missing transits, so that I could end up with a dataframe3 looking
> > as follows:
> >
> > <dataframe3
> > Date Transits
> > 1985-10-01 15
> > 1985-11-01 NA
> > 1985-12-01 NA
> > 1986-01-01 20
> > 1986-02-01 5
> > 2017-03-01 NA
> >
> > This is what I want to accomplish.
> >
> > Thanks, beforehand for your help,
> >
> > Best regards,
> >
> > Paul
> >
> >
> > 2017-03-27 15:15 GMT-05:00 Mark Sharp <msharp at txbiomed.org <mailto:msharp at txbiomed.org>>:
> >
> >> Make some small dataframes of just a few rows that illustrate the problem
> >> structure. Make a third that has the result you want. You will get an
> >> answer very quickly. Without a self-contained reproducible problem,
> > results
> >> vary.
> >>
> >> Mark
> >> R. Mark Sharp, Ph.D.
> >> msharp at TxBiomed.org
> >>
> >>
> >>
> >>
> >>
> >>> On Mar 27, 2017, at 3:09 PM, Paul Bernal <paulbernal07 at gmail.com <mailto:paulbernal07 at gmail.com>> wrote:
> >>>
> >>> Dear friends,
> >>>
> >>> I have one dataframe which contains 378 observations, and another one,
> >>> containing 362 observations.
> >>>
> >>> Both dataframes have two columns, one date column and another one with
> >> the
> >>> number of transits.
> >>>
> >>> I wanted to come up with a code so that I could fill in the dates that
> >> are
> >>> missing in one of the dataframes and replace the column of transits with
> >>> the value NA.
> >>>
> >>> I have tried several things but R obviously complains that the length of
> >>> the dataframes are different.
> >>>
> >>> How can I solve this?
> >>>
> >>> Any guidance will be greatly appreciated,
> >>>
> >>> Best regards,
> >>>
> >>> Paul
> >>>
> >>> [[alternative HTML version deleted]]
> >>>
> >>> ______________________________________________
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> >> posting-guide.html
> >>> and provide commented, minimal, self-contained, reproducible code.
> >>
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> > [[alternative HTML version deleted]]
> >
> > ______________________________________________
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> >
> > [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help at r-project.org <mailto:R-help at r-project.org> mailing list -- To UNSUBSCRIBE and more, see
> > https://stat.ethz.ch/mailman/listinfo/r-help <https://stat.ethz.ch/mailman/listinfo/r-help>
> > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html <http://www.r-project.org/posting-guide.html>
> > and provide commented, minimal, self-contained, reproducible code.
>
>
> <Container.csv>
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