[R] plot different groups as factors

[Jim Lemon]

On 12/19/2013 11:18 AM, Luigi Marongiu wrote:
> dear all,
> i would like to plot the value of different response groups. when i simply
> use  plot(y ~ x) i obtain a series of boxplots. i would rather use dots. i
> also tried with stripchart(y ~ x), which gives better results but does not
> place properly the labels since place them alphabetically.
> in addition i actually have 6 response groups: 3 classes (low, medium,
> high) and 2 sampling time (12 and 18 months).
> how can i generate these individual groups and plot them in the correct
> order (low, medium, high and 12, 18)? i believe is something to do with the
> factors but i don't know how to implement them.

Hi Luigi,
Perhaps you want something like this:

lmdf<-read.table(text="time class value
18 medium 2.92
18 medium 0.01
18 medium 0.36
18 medium 3.16
18 medium 0.99
18 medium 0.38
18 medium 0.01
18 medium 5.1
18 medium 0.04
18 medium 0.01
18 medium 1.33
18 medium 4.13
18 medium 0.15
18 medium 0.15
18 high 14.18
18 high 4290.14
18 high 26.8
18 high 5.33
18 high 17.58
18 high 14.29
18 high 248.5
18 low 0.01
18 low 0
18 low 0
18 low 0
18 low 0
18 low 0
18 low 0
12 medium 0.151395382
12 medium 5.327863403
12 medium 5.10096383
12 medium 1.32567787
12 medium 4.352404124
12 medium 0.458606982
12 medium 2.915908912
12 medium 0.011996374
12 medium 0.364710382
12 medium 0.033016026
12 medium 3.161701212
12 medium 0.381564497
12 medium 0.010971385
12 medium 0.035646472
12 medium 0.014781805
12 medium 4.129708296
12 medium 0.153094117
12 medium 0.018497847
12 high 15.09178491
12 high 17.58393041
12 high 14.17643928
12 high 4290.143561
12 high 26.79730719
12 high 294.6367065
12 high 14.2888441
12 high 248.495231
12 high 209.3131795
12 high 2014.506722
12 low 0.010751273
12 low 0.002325138
12 low 0.000637473
12 low 0.003984336
12 low 0.006018154
12 low 0.003620907
12 low 7.46E-05
12 low 0.000142311
12 low 0.002460417
12 low 0.001280189",header=TRUE)

# get the factor levels in the correct order
lmdf$class<-factor(lmdf$class,levels=c("low","medium","high"))
library(plotrix)
brkdn.plot("value","class","time",lmdf,col=2:4)
legend(14,1200,c("low","medium","high"),col=2:4,lty=1)

Jim