[R] Merging data frames of different length

[Dimitri Liakhovitski]

Hello, everyone!

I have list L that contains 99 data frames. All data frames have only
one row, but a different number of columns. Some data frames have 3
columns, some - 6 columns, and some - 9 columns. The names of the
first 3 columns are identical in all 99 data frames (e.g., A, B, and
C). The names of columns 4:6 are identical in data frames that contain
6 and 9 columns (e.g., D, E, and F). So that L looks like this:

L[[1]]
A B C
2 3 4
L[[2]]
A B C D E F
2 1 3 2 4 5
L[[3]]
A B C D E F G H I
1 2 4 3 2 4 5 4 2
L[[4]]
...


How can I merge all of those data frames into one large data frame -
with 99 rows - such that all data are in the columns with correct
names. Of course, I'd like the rows of the new large data frame that
contain the data for less than 9 columns to have NAs in columns 4:9
(or 7:9).
In other words, I want the first 3 rows of the new large data frame to
look like this:
A B C D E F G H I
2 3 4 NA NA NA NA NA NA
2 1 3 2 4 5 NA NA NA
1 2 4 3 2 4 5 4 2

Ideally, I'd like this merge to work for ANY number of individual
small data frames in L - even if their total number within L is
unknown.

I tried merge - but it seems to me that it only works for 2 data
frames, not for many.
Thank you very much!
-- 
Dimitri Liakhovitski
MarketTools, Inc.