[R] Looping Through DataFrames with Differing Lenghts

Paul Bernal
Mon, 27 Mar 2017 20:49:16 -0000

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>:

> 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> 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]]
> >
> > ______________________________________________
> > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> > 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.
>
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