[R] Function rank() for data frames (or multiple vectors)?

[David Winsemius]

On Aug 24, 2011, at 1:11 PM, Sebastian Bauer wrote:

> Hi!
>
>>> I'd like to rank rows of a data frame similar to what rank() does
>>> for vectors. However, ties should be broken by columns that I
>>> specify. If it is not possible to break a ties (because the row data
>>> is essentially the same), I'd like to have the same flexibility that
>>> rank() offers. Is there an elegant solution to this simple problem
>>> in R? Basically, what I need is a mixture of order() and rank().
>>> While the former allows to specify multiple vectors, it doesn't
>>> provide the flexibility of rank() such that I can specify what
>>> happens if ties can not be broken.
>> An example of this "simple problem" would clarify this greatly. I
>> cannot tell what "flexibility" in 'rank' is missing in 'order'.
>
> Thanks for your answer. For instance, if I have two vectors such as
>
> 1 1
> 1 2
> 1 2
> 1 3
> 2 1
>
> that I want combinedly ranked. I'd like to get an output
>
> 1
> 2
> 2
> 4
> 5
>
> or (ties.method=average)
>
> 1
> 2.5
> 2.5
> 4
> 5
>
> Basically, I need a function similar to the rank() function that  
> accepts
> more than one vector (as order() does).

Can't you just paste the columns and run rank on the results? 'rank'  
accepts character vectors.

>
> Best,
> Sebastian
>

David Winsemius, MD
West Hartford, CT