how to convert by lists in data.frames

On Tue, Oct 9, 2012 at 12:25 PM, Bert Gunter <gunter.berton at gene.com> wrote:

The only wrinkle here (with either rbind or simplify2array) is getting
the labels correct if the design is not fully crossed -- i.e. if some
groups are missing so that expand.grid() won't work. Then you might
have to work harder to extract the information from by.list.

Agreed. In such a case I might decide to let

  aggregate(breaks~wool+tension, subset(warpbreaks, wool != 'A' | tension !=
'H' ), summary)

sort through the headache for me, and overlook the annoying "result is
actually a matrix put in as a single variable in the data.frame". Personal
preference maybe but that never made sense to me in the data frame
construct (even if it is just a list).
Cheers

str(by.list)

might help here.

-- Bert

On Tue, Oct 9, 2012 at 11:14 AM, ilai <keren at math.montana.edu> wrote:

On Tue, Oct 9, 2012 at 11:42 AM, Rui Barradas <ruipbarradas at sapo.pt>

wrote:

Hello,

Try

do.call(data.frame, by.list)

I don't think data.frame inside do.call works in this context. May need

it

on the outside to do the job (Only OK here since there is no mixture of
numeric and character/factors in this summary). Something like

by.list <- by(warpbreaks[, 1], warpbreaks[, -1], summary)
by.dtfrm <- data.frame( do.call( rbind, by.list ) )
by.dtfrm <- cbind( do.call( expand.grid, attr( by.list, 'dimnames' ) ),
by.dtfrm )




Hope this helps,

Rui Barradas
Em 09-10-2012 17:53, Jesus Frias escreveu:

Dear R-helpers,



I've got a summary of results from a by() call that I am making with a

list

of more than two of factors not very different from the example in the

by()

help page



require(stats)

by(warpbreaks[, 1],   warpbreaks[, -1],       summary)



The result of the command gives a list of the form



wool: A
tension: L
     Min. 1st Qu.  Median    Mean 3rd Qu.    Max.
    25.00   26.00   51.00   44.56   54.00   70.00
---------------------------------------------------
wool: B
tension: L
     Min. 1st Qu.  Median    Mean 3rd Qu.    Max.
    14.00   20.00   29.00   28.22   31.00   44.00
---------------------------------------------------

.... And so on.





I would like to convert this result in to a flat data.frame with

variable

names:



Wool, Tension, Min, 1stQ, Median, Mean, 3rdQ, Max

A, L , 25.00   26.00   51.00   44.56   54.00   70.00
B,  L, 14.00   20.00   29.00   28.22   31.00   44.00

....





Although I've tried the argument "simplify=T" I haven't been able to

get

this converted.



Is there a simple way to achieve this?



Thanks in advance!



Regards,



Jesus



Jes?s Mar?a Fr?as Celayeta, PhD

Ceann C?nt?ir, Scoil Eola?ocht an Bhia agus Sl?inte an Chomhshaoil

Assistant Head, School of Food Science and Environmental Health,

Col?iste Eola?ochta? agus Sl?inte/ College of Sciences and Health,

Institi?id Teicneola?ochta ?tha Cliath/ Dublin Institute of

Technology,

Sr?id Chathal Brugha, Baile ?tha Cliath 1, ?ire/Cathal Brugha Street,

Dublin

1, Ireland

F: +353-1-4024459

E:  <mailto:james.curtin at dit.ie> jesus.frias at dit.ie

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