[R] How to change variables in datasets automatically

[Muhammad Subianto]

Excellent, this is exactly what I was looking for.
Many thanks and best regards,
Muhammad Subianto


On 4/29/05, Liaw, Andy <andy_liaw at merck.com> wrote:
> Try:
> 
> a <- data.frame(Sepal.Length=1:4, Sepal.Width=2:5,
>                 Petal.Length=3:6, Petal.Width=4:7,
>                 Species=rep("rosa",4))
> b <- iris[1:10,]
> newtest.iris <- rbind(a,b)
> names(newtest.iris) <- c("SL", "SW", "PL", "PW", "Class")
> newtest.iris$Class <- as.numeric(newtest.iris$Class) - 1
> 
> HTH,
> Andy
> 
> > From: Muhammad Subianto
> >
> > Dear R-helpers,
> > Suppose I have a dataset,
> >  data(iris)
> >  a <- data.frame(Sepal.Length=c(1:4), Sepal.Width=c(2:5),
> > Petal.Length=c(3:6), Petal.Width=c(4:7), Species=rep("rosa",4))
> >  b <- iris[1:10,]
> >  newtest.iris <- rbind(a,b)
> > >  newtest.iris
> >    Sepal.Length Sepal.Width Petal.Length Petal.Width Species
> > 1           1.0         2.0          3.0         4.0    rosa
> > 2           2.0         3.0          4.0         5.0    rosa
> > 3           3.0         4.0          5.0         6.0    rosa
> > 4           4.0         5.0          6.0         7.0    rosa
> > 11          5.1         3.5          1.4         0.2  setosa
> > 21          4.9         3.0          1.4         0.2  setosa
> > 31          4.7         3.2          1.3         0.2  setosa
> > 41          4.6         3.1          1.5         0.2  setosa
> > 5           5.0         3.6          1.4         0.2  setosa
> > 6           5.4         3.9          1.7         0.4  setosa
> > 7           4.6         3.4          1.4         0.3  setosa
> > 8           5.0         3.4          1.5         0.2  setosa
> > 9           4.4         2.9          1.4         0.2  setosa
> > 10          4.9         3.1          1.5         0.1  setosa
> >
> > I want to change each labels (variables) like:
> > Sepal.Length=SL, Sepal.Width=SW,
> > Petal.Length=PL, Petal.Width=PW, and Species=Class. Then I want to
> > change each cell
> > in Species variable like rosa=0 and setosa=1. The result
> > something like this,
> >
> > >  NewIris
> >     SL  SW  PL  PW Class
> > 1  1.0 2.0 3.0 4.0     0
> > 2  2.0 3.0 4.0 5.0     0
> > 3  3.0 4.0 5.0 6.0     0
> > 4  4.0 5.0 6.0 7.0     0
> > 5  5.1 3.5 1.4 0.2     1
> > 6  4.9 3.0 1.4 0.2     1
> > 7  4.7 3.2 1.3 0.2     1
> > 8  4.6 3.1 1.5 0.2     1
> > 9  5.0 3.6 1.4 0.2     1
> > 10 5.4 3.9 1.7 0.4     1
> > 11 4.6 3.4 1.4 0.3     1
> > 12 5.0 3.4 1.5 0.2     1
> > 13 4.4 2.9 1.4 0.2     1
> > 14 4.9 3.1 1.5 0.1     1
> > >
> > I can do it the result above like this,
> >
> > >  Class <- ifelse(newtest.iris$Species=="rosa", 0, 1)
> > >  NewIris <- data.frame(SL = newtest.iris$Sepal.Length,
> > +                        SW = newtest.iris$Sepal.Width,
> > +                        PL = newtest.iris$Petal.Length,
> > +                        PW = newtest.iris$Petal.Width,
> > +                        Class)
> >
> > Because I have more variables in my datasets which I must to change.
> > Is there any way to change automatically and which library contains a
> > function to compute that?
> > I  would be very happy if anyone could help me.
> > Thank you very much in advance.
> >
> > Kindly regards,
> > Muhammad Subianto
> >
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> >
> >
> >
> 
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