R help - Dec 2005 - how to change a dataframe with characters to a numeric matrix?

hi netters,

i have a dataframe TEST like this:

   Y1 Y2 Y3
X1  4  7  8
X2  6  2  Z
X3  8  0  1

i would like to change it to a numeric matrix, replacing "Z" with NA

   Y1 Y2 Y3
X1  4  7  8
X2  6  2  NA
X3  8  0  1

i've tried the function data.matrix but it didn't work. is there any
easy
way to do this?

thanks a lot!

A way to do it :

TEST$Y3[TEST$Y3=="Z"] <- NA

TEST$Y3 <- as.numeric(TEST$Y3)


2005/12/8, zhihua li <lzhtom@hotmail.com>:
>
> hi netters,
>
> i have a dataframe TEST like this:
>
>   Y1 Y2 Y3
> X1  4  7  8
> X2  6  2  Z
> X3  8  0  1
>
> i would like to change it to a numeric matrix, replacing "Z" with
NA
>
>   Y1 Y2 Y3
> X1  4  7  8
> X2  6  2  NA
> X3  8  0  1
>
> i've tried the function data.matrix but it didn't work. is there
any easy
> way to do this?
>
> thanks a lot!
>
>
>
> ______________________________________________
> R-help@stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
> http://www.R-project.org/posting-guide.html
>
>

--
David

	[[alternative HTML version deleted]]

you probably have a dataframe like this :
z <- data.frame(y1=c(1,2,3),y2=c(4,5,6),y3=c(4,"z",5))

you can do :
z <- as.matrix(z)
mode(z) <- "numeric"




zhihua li a 仺仸crit :
> hi netters,
>
> i have a dataframe TEST like this:
>
> Y1 Y2 Y3
> X1 4 7 8
> X2 6 2 Z
> X3 8 0 1
>
> i would like to change it to a numeric matrix, replacing "Z" with
NA
>
> Y1 Y2 Y3
> X1 4 7 8
> X2 6 2 NA
> X3 8 0 1
>
> i've tried the function data.matrix but it didn't work. is there
any
> easy way to do this?
>
> thanks a lot!
>
>------------------------------------------------------------------------
>
>______________________________________________
>R-help at stat.math.ethz.ch mailing list
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html
>