[R] by funtion

[Petr PIKAL]

Hi

r-help-bounces at r-project.org napsal dne 29.04.2010 08:11:41:

> Hi
> 
> you could try
> 
> do.call('rbind',aa)

No, No, No. rbind and cbind binds vectors as rows or columns of 
***matrix***, result is not a data frame

do.call("rbind",aa)
    X069rutil X102anatas
105      26.9        7.9
200      22.8       10.6
400      30.6       13.3
600      50.8       20.6
800      78.7         NA
exp.df<-do.call("rbind",aa)
str(exp.df)
 num [1:5, 1:2] 26.9 22.8 30.6 50.8 78.7 7.9 10.6 13.3 20.6 NA
 - attr(*, "dimnames")=List of 2
  ..$ : chr [1:5] "105" "200" "400" "600" ...
  ..$ : chr [1:2] "X069rutil" "X102anatas"

If some object has rectangular shape and has column names it does not 
automatically mean that it is data frame

Regards
Petr


>

> 
> then turn the matrix into data frame
> 
> regards
> 
> Tengfei
> 
> On Wed, Apr 28, 2010 at 10:56 PM, Yuan Jian <jayuan2008 at yahoo.com> 
wrote:
> 
> > Hello,
> >
> > I have a data.frame:
> > name    col1    col2    col3    col4
> > AA    23    54    0.999    0.78
> > BB    123    5    1    0.99
> > AA    203    98    0.79    0.99
> >
> > I want to get mean value data.frame in terms of name:
> >
> > name    col1    col2    col3    col4
> >
> > AA    113.0000  76.0000   0.8945   0.8850
> >
> > BB    123.00   5.00   1.00   0.99
> >
> > I tried to use by function:
> >
> > >aa<-by(test[,2:5], feature, mean)
> > I found aa is "by" function.
> > > class(aa)
> > [1] "by"
> >
> > how can I transfer aa to a data frame?
> >
> > thanks
> > YU
> >
> >
> >
> >
> >
> >
> >        [[alternative HTML version deleted]]
> >
> >
> > ______________________________________________
> > 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.
> >
> >
> 
> 
> -- 
> Tengfei Yin
> MCDB PhD student
> 1620 Howe Hall, 2274,
> Iowa State University
> Ames, IA,50011-2274
> Homepage: www.tengfei.name
> 
>    [[alternative HTML version deleted]]
> 
> ______________________________________________
> 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.