I have much more problem in the following case:

 Years   Products  New Column
 1          10           0
 2          25           0
 3          40           0
 4          NA          0
 5          35           0
<NA>    23           1
 6         NA           0
 7         67            0
 8         NA           0
NA       NA           *NA*
NA       NA           *NA*

When i hane NA in both columns the results of the procedure give me NA.
I'd like to obtain 0.



2007/4/3, Mark Wardle <mark@wardle.org>:
>
> Sergio Della Franca wrote:
> > Dear R-Helpers,
> >
> > I have the following data set(y):
> >
> > Years   Products
> > 1          10
> > 2          25
> > 3          40
> > 4          NA
> > 5          35
> > <NA>   23
> > 6         NA
> > 7         67
> > 8         NA
> >
> > I want to create a new column into my dataset(y) under the following
> > conditions:
> > if years =NA and products >20 then new column=1 else new column=0;
> > to obtain the following results:
> >
> > Years   Products New Column
> > 1          10          0
> > 2          25          0
> > 3          40          0
> > 4          NA         0
> > 5          35          0
> > <NA>   23          1
> > 6         NA          0
> > 7         67           0
> > 8         NA          0
> >
>
> How about using ifelse():
> year = c(1,2,3,4,5,NA,6,7,8)
> products = c(10,25,40,NA,35,23,NA,67,NA)
> ifelse(is.na(year) & products>20,1,0)
>
>
> =>
>
> [1] 0 0 0 0 0 1 0 0 0
>
>
> Mark
>
> --
> Dr. Mark Wardle
> Specialist registrar, Neurology
> Cardiff, UK
>

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