Looping Through DataFrames with Differing Lenghts

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>

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> 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>:

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]]

posting-guide.html

CONFIDENTIALITY NOTICE: This e-mail and any files and/or attachments
transmitted, may contain privileged and confidential information and is
intended solely for the exclusive use of the individual or entity to

whom

it is addressed. If you are not the intended recipient, you are hereby
notified that any review, dissemination, distribution or copying of this
e-mail and/or attachments is strictly prohibited. If you have received

this

e-mail in error, please immediately notify the sender stating that this
transmission was misdirected; return the e-mail to sender; destroy all
paper copies and delete all electronic copies from your system without
disclosing its contents.

       [[alternative HTML version deleted]]

posting-guide.html

posting-guide.html