r - rbind error: "names do not match previous names"

Question

As part of a larger problem (adding a ,makeUniqueIDs argument to rbind.SpatialPolygonsDataFrame for situations when the polygon IDs are identical), I'm running into this weird message from rbind:

> do.call("rbind",xd.small)
Error in match.names(clabs, names(xi)) : 
  names do not match previous names

• xd.small dput output

The only other info I could find on this was this question, which leads me to believe that rbind was at the root of the problem there also.

I can just write my own rbind-like function of course, but presumably this match.names check occurs for a reason, and I'm curious what it is.

Answer 1

The names (column names) of the first dataframe do not match the names of the second one. Just as the error message says.

> identical(names(xd.small[[1]]), names(xd.small[[2]]) )
[1] FALSE

If you do not care about the names of the 3rd or 4th columns of the second df, you can coerce them to be the same:

> names(xd.small[[1]]) <- names(xd.small[[2]]) 
> identical(names(xd.small[[1]]), names(xd.small[[2]]) )
[1] TRUE

Then things should proceed happily.