missing value with sign observed

kate <yhsu6 <at> uiuc.edu> writes:

[snip]

When I read this txt file into R and attach this data, I found the output of y

is as the follows

[1] 8  5  3  +  -1 + 
Levels: -1 + 3 5 8

Could I get rid of Levels in the output? Because I need to use the observed y

and x run regression first and then

assign the value to the missing y later.

You probably want to use the argument na.strings="+" in your
input command (scan or read.table) -- R is interpreting the
existence of a non-numeric value in your input as evidence
that you want that variable to be a factor (a categorical,
non-numeric variable).

  Ben Bolker