[R] xmat[1, 2:3] <- NULL

From: Mikkel Grum <mi2kelgrum_at_yahoo.com>
Date: Fri 08 Jul 2005 - 03:20:26 EST


I have a situation where I'm filling out a dataframe from a database. Sometimes the database query doesn't get anything, so I end up trying to place NULL in the dataframe like below.

> temp <- NULL
> xmat <- as.data.frame(matrix(NA, 2, 3))
> xmat[1, 2:3] <- temp

Error in if (m < n * p && (n * p)%%m)
stop(gettextf("replacement has %d items, need %d", :

        missing value where TRUE/FALSE needed

I can't get the programme to accept that sometimes what the query looks for just doesn't exist, and I just want to move on to the next calculation leaving the dataframe with a missing value in the given cell. It's a real show stopper and I haven't found a way round it.

Best wishes,
Mikkel

PS. I'm using dbGetQuery to query an SQLite database.



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