[R] Odp: working with tables -- was Re: Mode (statistics) in R?

[Petr PIKAL]

Hi

r-help-bounces at r-project.org napsal dne 27.01.2009 01:50:39:

> Ok, so I'm slowly figuring out what a factor is, and was able to follow
> the related thread about finding a mode by using constructs like
> 
> my_mode = as.numeric(names(table(x))[which.max(table(x))])
> 
> 
> Now, suppose I want to keep looking for other modes?  For example,

Do you mean the situation when there are more then one max values?

set.seed(19)
sample(seq(1,10),50,replace=TRUE)->bag
table(bag)[max(table(bag))==table(bag)]

Regards
Petr


> 
> Rgames> sample(seq(1,10),50,replace=TRUE)->bag
> Rgames> bag
>   [1]  2  8  8 10  7  3  2  9  8  3  8  9  6  6 10 10  7  1
> [19]  9  5  4  3  3  5 10  3  6  3  2  8  4  2  1 10  6  2
> [37]  6  6  9  8  6  8  8  4  3  6  3  9  5  1
> Rgames> names(which.max(table(bag)))
> [1] "3"
> 
> I can then do
> 
> Rgames> bag2<-bag[bag!=3]
> 
> and repeat the which.max stuff.
> I came up with the following command to find the actual magnitude of the 

> mode:
> 
> Rgames> table(bag)->tbag
> Rgames> tbag
> bag
>   1  2  3  4  5  6  7  8  9 10
>   3  5  8  3  3  8  2  8  5  5
> 
> Rgames> tbag[dimnames(tbag)$bag=="3"]->bagmode
> Rgames> bagmode
> 3
> 8
> 
> 
> Related to this, since bag2 is now bereft of threes,
> Rgames> table(bag2)
> bag2
>   1  2  4  5  6  7  8  9 10
>   3  5  3  3  8  2  8  5  5
> 
> I was able to make the same table with
> 
> Rgames> newtable<-tbag[c(dimnames(tbag)$bag)!="3"]
> Rgames> newtable
> bag
>   1  2  4  5  6  7  8  9 10
>   3  5  3  3  8  2  8  5  5
> 
> 
> Is there a cleaner syntax to do these things?
> 
> Thanks for your help--and feel free to point me to the Inferno or other 
> paper on the philosophy and use of factors and tables.
> 
> Carl
> 
> ______________________________________________
> R-help at 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.