[R] Changing values (factors) does not change levels of that value?!

[Oliver Bandel]

Hello,


 * I read in a server weblog with read.table.
   -> OK.

 * I look for the downloaded-size-values (filesize of the download)
   -> OK

 * I found "-" and wanted to substitute them with "0" and
   used:  weblog$V8[ weblog$V8 == "-" ] <- 0
   -> OK

 * checked the contents on "-" vs. "0" and found all "-" substituted by
0
  -> OK

 * when then looking at str(weblog),
   the "-" will stay in the levels, mentioned for the variable weblog$V8
   -> BAD!

Is this snormal behaviour?
Do I have to throw out the unwanted level by myself?

Ciao,
   Oliver