names<- in data.frame (PR#13916)

It does work correctly:
names(tdf)
[1] "" ""

The thing you have overlooked is that data frames are required to have 
non-empty (not 'zero-length': yours has length 2) names, and the print 
method has created some (as data.frame will if you give unnamed 
arguments).

Please be careful to distinguish between an object and its printed 
representation.

Full_Name: Spinu Vitalie
Version: 2.9.0
OS: Windows
Submission from: (NULL) (130.115.113.15)

In assignment of "zero length" names to data.frame:

tdf <- data.frame(rbind(c(1, 2), c(1, 2)))
names(tdf) <- c("", "")
tdf
 structure(c("1", "1"), class = "AsIs") structure(c("2", "2"), class = "AsIs")
1                                      1                                      2
2                                      1                                      2

For vectors it works nicely:

tv <- c(1, 2)
names(tv) <- c("", "")
tv
1 2

sessionInfo()
R version 2.9.0 (2009-04-17)
i386-pc-mingw32

locale:
LC_COLLATE=English_United States.1252;LC_CTYPE=English_United
States.1252;LC_MONETARY=English_United
States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252

attached base packages:
[1] stats     graphics  uti

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Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
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