mixed success- how to remove rows with missing factor value in it?

["Danni Wang" <wangdn@uclink4.berkeley.edu>]

- This works 

When you say they are missing, are they really 'blank'?  I would assume
that if they are characters, then missing values are blank, so the
following should work;

data[-which(data$timestamp==" "),]

- There are also circumstances that missing strings are NA, such as

> data
V1      V2      timestamp
1       2       a
3       4       NA
NA      7       NA
45      NA      c
9       6       d

data[-which(data$timestamp=="NA"),] doesn't work.

Regard,