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

[Mikkel Grum]

Thanks for this! This is even simpler than using
!is.null():

xmat <- as.data.frame(matrix(NA, 2, 3))
try(xmat[i, 2:3] <- dbGetQuery(...), silent = TRUE)

Best wishes,
Mikkel

--- Uwe Ligges <ligges at statistik.uni-dortmund.de>
wrote:

> Mikkel Grum wrote:
> 
> > 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.
> 
> 
> See ?try
> 
> Uwe Ligges
> 
> 
> > Best wishes,
> > Mikkel
> > 
> > PS. I'm using dbGetQuery to query an SQLite
> database.
> > 
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