Merging two datasets

From: rkevinburton at charter.net <rkevinburton at charter.net>
Subject: Re: [R] Merging two datasets
To: "Henrique Dallazuanna" <wwwhsd at gmail.com>, "Shreyasee Pradhan" <shreyasee.pradhan at gmail.com>
Cc: r-help at r-project.org
Received: Wednesday, August 6, 2008, 12:10 PM
I looked at 'merge'. What if df1 and df2 are
data.frames and I want to merge on on column and sum on
another? Say df1 and df2 are data.frames with columns
'ID1', 'ID2', 'ID3', and
'Qty'. I want to 'merge' the data frames
(and produce a new data.frame) if there is a matching
'ID2' in each data.frame and if there is sum the
'Qty' value from each data fame. First, I don't
see a function that can be applied during the merge. Maybe
that has to be done in a separate step. Next,
'merge' seems to produce a data.frame with the
columns renamed. How can I preserve the column names?

Thank you.


Kevin

---- Henrique Dallazuanna <wwwhsd at gmail.com> wrote: 

Try using:

merge(df1, df2, all = TRUE)

On Wed, Aug 6, 2008 at 11:15 AM, Shreyasee Pradhan
<shreyasee.pradhan at gmail.com> wrote:

I am facing a problem in merging two datasets.
I have given codes to the names which are common

in both the datasets and

also to those which are uncommon.
When I gave gave the following command

merge(df1,df2)

only those rows and columns were merged which

were  having common codes.

When I viewed the results, only common codes are

seen and the remaining

entries are not seen.

Can anyone guide me in this regards?
How should I merge these two datasets completely

without loss of any

information?

Thanks,
Shreyasee

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