[R] Help in getting info from a DataFrame

[Petr PIKAL]

Hi

r-help-bounces at r-project.org napsal dne 02.02.2011 11:14:18:

> 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?

Sorry I did not look to your code and used the code I sent you as a 
solution

What do you expect max(lapsales$qtg) give you as a result?
If you changed the number qtd to 4 instead of 3 you will get

> lapsales[max(lapsales$qtd),"Store"]
[1] <NA>
Levels: Aveiro Coimbra Evora lx Setubal

So R give you what you ask for. You asked for third line and you got it.

If you asked for which position is the maximum number

lapsales[which.max(lapsales$qtd),"Store"]
[1] Aveiro
Levels: Aveiro Coimbra Evora lx Setubal

You will get desired result.

Regards
Petr



> 
> 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
> 
> 
> 
> 
> 
> > 
> > thanks
> > AD
> > -- 
> > View this message in context: 
> http://r.789695.n4.nabble.com/Help-in-getting-
> > info-from-a-DataFrame-tp3247740p3248883.html
> > Sent from the R help mailing list archive at Nabble.com.
> > 
> > ______________________________________________
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