[R] flattening return value of tapply

Vadim Ogranovich vograno at arbitrade.com
Sat Dec 29 00:10:34 CET 2001

Dear R-Users,

Does anyone know how to flatten, i.e. convert to a table, a return value of
tapply when its INDEX argument is a list? Here is an example of what I need

> x <- rnorm(100)
> f1 <- rep(c(T,F),50)
> f2 <- c(rep(T,50), rep(F,50))
> y <- tapply(x, list(f1=f1,f2=f2), summary)
> y
f1      FALSE       TRUE       
  FALSE "Numeric,6" "Numeric,6"
  TRUE  "Numeric,6" "Numeric,6"

# I'd like 'y' to be printed as a table with rows corresponding to factor
# The closest I could get to it is this
> t(sapply(y, I))
       Min. 1st Qu.  Median     Mean 3rd Qu.  Max.
[1,] -1.616 -0.5475 0.17450  0.26030  0.9742 2.117
[2,] -2.038 -0.8990 0.02546 -0.13390  0.2461 1.874
[3,] -2.344 -0.5494 0.07578  0.02965  0.5424 1.974
[4,] -1.660 -0.4915 0.41760  0.17750  0.9652 1.629

but this doesn't produce meaningful row names.

Any suggestion?

Thank you,

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