That's great! But, I guess I should have provided a better example for 
my problem. The reason being that I did not consider strings. For 
instance, in my case, I'm actually trying to add a value to a data frame 
that looks like this:

Obs     X
0     NA
1     "01 001"
2     "01 002"
3     "01 003"

And I am actually trying to get that specific "NA" value and convert it 
to "00 000" so it can look like this:

Obs     X
0     "00 000"
1     "01 001"
2     "01 002"
3     "01 003"

When I write the code you provided, I get this result:

x[1,"X"]<-"00 000"
Warning message:
In `[<-.factor`(`*tmp*`, iseq, value = c(NA, 3L, 4L, 5L, 6L, 7L,  :

invalid factor level, NAs generated

I am wondering what I am doing wrong and how to solve this problem.

Thanks for all the help!

Carlos



On 6/10/2011 8:34 PM, jholtman [via R] wrote:
> you probably need to read the Introduction to R to understand indexing:
>
> > x
>   Obs X Y Z
> 1   1 1 0 1
> 2   2 0 0 1
> 3   3 1 1 1
> 4   4 0 1 1
> 5   5 1 1 0
> 6   6 0 0 0
> > x[4, "Y"] <- 0
> > x
>   Obs X Y Z
> 1   1 1 0 1
> 2   2 0 0 1
> 3   3 1 1 1
> 4   4 0 0 1
> 5   5 1 1 0
> 6   6 0 0 0
>
>
> On Fri, Jun 10, 2011 at 5:42 PM, jour4life <[hidden email] 
> </user/SendEmail.jtp?type=node&node=3589793&i=0>> wrote:
>
> > Hello all,
> >
> > I am wondering if there is a way to change the value of one cell in 
> R. For
> > instance let's say I have a hypothetical data frame that looks like 
> this:
> >
> > Obs X Y Z
> > 1    1 0 1
> > 2    0 0 1
> > 3    1 1 1
> > 4    0 1 1
> > 5    1 1 0
> > 6    0 0 0
> >
> > I would like to change the value of the 4th observation in the Y 
> column from
> > 1 to 0. It should look like this:
> >
> > Obs X Y Z
> > 1    1 0 1
> > 2    0 0 1
> > 3    1 1 1
> > 4    0 0 1
> > 5    1 1 0
> > 6    0 0 0
> >
> > Is it possible to change the value in one command?
> >
> > Thanks,
> >
> > Carlos
> >
> >
> > --
> > View this message in context: 
> http://r.789695.n4.nabble.com/change-value-in-one-cell-tp3589456p3589456.html
> > Sent from the R help mailing list archive at Nabble.com.
> >
> > ______________________________________________
> > [hidden email] </user/SendEmail.jtp?type=node&node=3589793&i=1> 
> mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide 
> http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
> >
>
>
>
> -- 
> Jim Holtman
> Data Munger Guru
>
> What is the problem that you are trying to solve?
>
> ______________________________________________
> [hidden email] </user/SendEmail.jtp?type=node&node=3589793&i=2> 
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>
>
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