Thanks David, I never thought of using merge for this.

I usually used the "cast" command from the "reshape" package for this type
of task.


Cheers,
Tal



----------------Contact
Details:-------------------------------------------------------
Contact me: Tal.Galili@gmail.com |  972-52-7275845
Read me: www.talgalili.com (Hebrew) | www.biostatistics.co.il (Hebrew) |
www.r-statistics.com (English)
----------------------------------------------------------------------------------------------




On Fri, Apr 2, 2010 at 11:31 PM, David Winsemius <dwinsemius@comcast.net>wrote:

>
> On Apr 2, 2010, at 3:39 PM, Geoffrey Smith wrote:
>
>  Hello, I have an unbalanced panel data set that looks like:
>>
>> ID,YEAR,HEIGHT
>> Tom,2007,65
>> Tom,2008,66
>> Mary,2007,45
>> Mary,2008,50
>> Harry,2007,62
>> Harry,2008,62
>> James,2007,68
>> Jack,2007,70
>> Jordan,2008,72
>>
>> That is, James, Jack, and Jordan are missing a YEAR.
>>
>> Is there any command that will "fill in" the missing YEAR such that the
>> end
>> result will be balanced and look like:
>>
>> ID,YEAR,HEIGHT
>> Tom,2007,65
>> Tom,2008,66
>> Mary,2007,45
>> Mary,2008,50
>> Harry,2007,62
>> Harry,2008,62
>> James,2007,68
>> James,2008,NA
>> Jack,2007,70
>> Jack,2008,NA
>> Jordan,2007,NA
>> Jordan,2008,72
>>
>
> It's not "one command" but it's an approach ...  assumes you have data in a
> dataframe named ftbl:
>
> > fexp <- expand.grid(ID=unique(ftbl$ID), YEAR=unique(ftbl$YEAR))
> > merge(fexp, ftbl, all=TRUE)
>
>       ID YEAR HEIGHT
> 1   Harry 2007     62
> 2   Harry 2008     62
> 3    Jack 2007     70
> 4    Jack 2008     NA
> 5   James 2007     68
> 6   James 2008     NA
> 7  Jordan 2007     NA
> 8  Jordan 2008     72
> 9    Mary 2007     45
> 10   Mary 2008     50
> 11    Tom 2007     65
> 12    Tom 2008     66
>
>
>
>  --
>
> David Winsemius, MD
> West Hartford, CT
>
>
> ______________________________________________
> R-help@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.
>

	[[alternative HTML version deleted]]

