Merging data frames of different length
Hi Dimitri,
Not exceptionally elegant, but this should do it:
alldata <- as.data.frame(matrix(as.numeric(NA),nrow=99,ncol=9))
colnames(alldata) <- colnames(L[[?]])
( where ? is a 9-column data frame with the correct names )
foreach (i in 1:99) {
alldata[i,colnames(L[[i]])] <- L[[i]]
}
--Adam
On Fri, 19 Dec 2008, Dimitri Liakhovitski wrote:
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.
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