Apprentice Piece with Lattice Graphs

Lattice graphs can be quite tedious. I don’t use them too often and  when I need them I usually have to dig the archives for the parameter-details.
The here presented example may serve as a welcome template for the usage of panel functions, panel ordering, for drawing of lattice keys, etc.
You can download the example data HERE.

(Also, check this resource with examples by the lattice-author himself). 

library(lattice)
df <- read.csv("PATH/TO/Downloads/lattice_data.csv",
               header = T, sep = ";")
mypch <- rep(21, 3)
mycol <- c(rgb(0.2, 0.8, 0.9), rgb(0.8, 0.2, 0.9), rgb(0.9, 0.2, 0.2))

stripplot(mean ~ group1 | item_parc, groups = group2, data = df,
          type = c("a", "p"), strip = strip.custom(strip.names = c(F, T)),
          ylab = "Score-Mittelwert", layout = c(2, 4),
          scales = list(y = list(cex = 0.9),
                        x = list(cex = 1.1, labels = c("männl.", "weibl."),
                        tck = c(1, 0))),
          par.strip.text = list(cex = 0.9),
          panel = function(...) {
             panel.stripplot(..., col = mycol, pch = mypch, fill = mycol)
          },
          index.cond = list(c(7,8,5,6,3,4,1,2)),
          key = list(space = "bottom", text = list(c("Alter < 35 J.",
                                                     "Alter 35-50 J.",
                                                     "Alter > 50 J.")),
                     points = list(col = mycol, cex = 0.8, pch = mypch, fill = mycol),
                     rep = F))