[R] Plot factors with a loop

[johannes rara]

Why do you need to do this using loop? Is this what you want?

a <- rep(c("a", "b", "c"), 6)
df <- data.frame(f=a, d=rnorm(18))
df
boxplot(df$d ~ df$f)


2009/9/20 Sam Player <samtplayer at gmail.com>:
> # I have a dataframe with a factor and data:
>
> a <- rep(c("a", "b"), c(6,6))
> df <- data.frame(f=a, d=rnorm(12))
> df
>
> # I want to make a single plot with boxplots of each factor. I need to do it
> via a loop as I would like to apply it to other dataframes with many
> factors. The following is a loop that produces a boxplot of the last factor,
> which overwrites the previous factor.
>
> for (i in levels(df$f)){
>        z <- assign(as.character(i), as.vector(df[df$f==i,2],
> mode="numeric"))
>        boxplot(z)
>        }
>
> # How can I stop the first factor being overwritten so that two boxplots are
> displayed in the plot. The result I need is also produced by:
>
> boxplot(df[df$f=="a",2], df[df$f=="b",2])
>
> # but I need it to be done through the loop. Thanks in advance!
>
> # Sam
>
> --
> Sam Player, B.Sc.(Hons.) B.A.
> Ph.D. Candidate, Faculty of Agriculture, Food & Natural Resources,
> University of Sydney
>
> Email: splayer at usyd.edu.au
>
> Agroecosystems Research Group
> Room 214 J.R.A. McMillan Building A05
> University of Sydney NSW 2006, Australia
>
> Angkor Research Program
> Room 305 Old Teachers College A22
> University of Sydney NSW 2006, Australia
>
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