[R] coef(summary) and plyr

[Hadley Wickham]

On Mon, Aug 9, 2010 at 4:30 PM, Matthew Dowle <mdowle at mdowle.plus.com> wrote:
>
>
> Another option for consideration :
>
> library(data.table)
> mydt = as.data.table(mydf)
>
> mydt[,as.list(coef(lm(y~x1+x2+x3))),by=fac]
>     fac X.Intercept.       x1       x2        x3
> [1,]   0  -0.16247059 1.130220 2.988769 -19.14719
> [2,]   1   0.08224509 1.216673 2.847960 -19.16105
> [3,]   2   0.02052320 1.135421 3.134154 -19.22555
>
> mydt[,data.table(coef(summary(lm(y~x1+x2+x3))),keep.rownames=TRUE),  by=fac]
>     fac          rn     Estimate Std..Error      t.value     Pr...t..
> [1,]   0 (Intercept)  -0.16247059  0.1521507   -1.0678269 2.929087e-01
> [2,]   0          x1   1.13021985  0.1374020    8.2256414 1.079035e-09
> [3,]   0          x2   2.98876920  0.1404903   21.2738533 1.325909e-21
> [4,]   0          x3 -19.14719151  0.1335139 -143.4096890 4.520371e-50
> [5,]   1 (Intercept)   0.08224509  0.2360664    0.3483981 7.313719e-01
> [6,]   1          x1   1.21667349  0.2723201    4.4678058 2.637743e-04
> [7,]   1          x2   2.84796003  0.2232960   12.7541904 9.192555e-11
> [8,]   1          x3 -19.16104669  0.2394431  -80.0233818 1.707058e-25
> [9,]   2 (Intercept)   0.02052320  0.1902526    0.1078734 9.147302e-01
> [10,]   2          x1   1.13542085  0.1786333    6.3561559  2.980475e-07
> [11,]   2          x2   3.13415398  0.1894404   16.5442781  7.827178e-18
> [12,]   2          x3 -19.22554984  0.1708307 -112.5415605  2.536686e-45

That reminds me:

library(reshape)
ldply(dl, function(x) namerows(as.data.frame(coef(summary(x)))))

I think both Matthew and I would agree that row names are a pain.

Hadley

-- 
Assistant Professor / Dobelman Family Junior Chair
Department of Statistics / Rice University
http://had.co.nz/