R devel - Jan 2000 - data.frame[1,1]<- differs from data.frame[[1]][1]<- (PR#403)

I observed the following difference:
> ddd <- data.frame(a=1:3, b=1:3)
# assignment of 'X' silently ignored
> ddd[1,1] <- 'X'
> is.factor(ddd[[1]])
[1] FALSE
> ddd
  a b
1 1 1
2 2 2
3 3 3

# assignment of 'X' not ignored
> ddd[[1]][1] <- 'X'
> is.factor(ddd[[1]])
[1] TRUE
> ddd
  a b
1 X 1
2 2 2
3 3 3


Regards


> version
         _
platform Windows
arch     x86
os       Win32
system   x86, Win32
status
major    0
minor    90.1
year     1999
month    December
day      15
language R


--
Dr. Jens Oehlschlägel-Akiyoshi
MD FACTORY GmbH
Bayerstrasse 21

80335 München

Tel.: 089 545 28-27
Fax.: 089 545 28-10
http://www.mdfactory.de



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> From: jens.oehlschlaegel-akiyoshi@mdfactory.de
> Date: Wed, 26 Jan 2000 17:24:05 +0100 (MET)
> 
> 
> I observed the following difference:
> 
> > ddd <- data.frame(a=1:3, b=1:3)
> 
> # assignment of 'X' silently ignored
> > ddd[1,1] <- 'X'
> > is.factor(ddd[[1]])
> [1] FALSE
> > ddd
>   a b
> 1 1 1
> 2 2 2
> 3 3 3
actually it assigns as.numeric(factor("X")), which is 1.
> # assignment of 'X' not ignored
> > ddd[[1]][1] <- 'X'
> > is.factor(ddd[[1]])
> [1] TRUE
> > ddd
>   a b
> 1 X 1
> 2 2 2
> 3 3 3
> 
Here is my solution: line 488 in dataframe.R, in "[<-.data.frame"

## careful, as.data.frame turns things into factors.
##    value <- as.data.frame(value)
    if(!is.list(value) && (missing(j) || !missing(i))) { # [i, ] or
[i,j]
        value <- matrix(value, n, p)
        dimv <- c(n, p)
        value <- split(value, col(value))
    } else {
        value <- as.data.frame(value)
        dimv <- dim(value)
    }

It covers the same cases as the prototype, but is a kludge, of course.

-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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