[R] Help in getting info from a DataFrame

[Petr PIKAL]

Hi

r-help-bounces at r-project.org napsal dne 31.01.2011 15:51:16:

> 
> 

<snip>


> > 
> > 
> 
> Hi
> 
> thanks. I am not sure if I have understood 100% but at least I know now 
that
> there's a diference.
> 
> About this: 
> 
> lapsales
>      Store      Prod qtd
>  5  Aveiro Lapiseira   3
>  8 Coimbra Lapiseira   1
>  9 Setubal Lapiseira   1
>  > lapsales[max(lapsales$qtd),"Store"]
>  [1] Setubal
>  Levels: Aveiro Coimbra Evora lx Setubal
> 
>  why Setubal and not Aveiro?
> 
> 
> Can you explain me the result?

Probably qtd is not what you think it is. I get

> dados<- data.frame(Store = c 
("Setubal","lx","Aveiro","Coimbra","Aveiro","Evora","Aveiro","Coimbra","Setubal"),Prod=c("BlocoDesenho","BlocoDesenho","Tinteiro","Régua","Lapiseira","Regua","Tinteiro","Lapiseira","Lapiseira"),qtd=c(2,1,2,1,3,1,1,1,1))
> lapsales <- dados[dados$Prod=="Lapiseira",  ]
> lapsales[which.max(lapsales[ , "qtd" ]), "Store"]
[1] Aveiro
Levels: Aveiro Coimbra Evora lx Setubal
> 

and

> str(lapsales)
'data.frame':   3 obs. of  3 variables:
 $ Store: Factor w/ 5 levels "Aveiro","Coimbra",..: 1 2 5
 $ Prod : Factor w/ 5 levels "BlocoDesenho",..: 2 2 2
 $ qtd  : num  3 1 1

Maybe you get something different.

Regards
Petr





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