Customize boxplot

Question

I have the following data:

structure(list(NotasMateriais...4. = c(1L, 2L, 8L, 5L, 5L, 4L, 
4L, 2L, 9L, 2L, 5L, 3L, 1L, 3L, 0L, 3L, 3L, 2L, 2L, 3L, 0L, 2L, 
14L, 0L, 0L, 3L, 6L, 3L, 4L, 3L), NotasMateriais...5. = c(3L, 
3L, 4L, 3L, 9L, 3L, 15L, 1L, 18L, 1L, 2L, 2L, 0L, 6L, 7L, 3L, 
12L, 4L, 3L, 8L, 2L, 2L, 12L, 1L, 0L, 7L, 6L, 3L, 2L, 4L), NotasMateriais...6. = c(4L, 
6L, 2L, 4L, 13L, 14L, 17L, 1L, 24L, 0L, 1L, 9L, 0L, 4L, 3L, 2L, 
16L, 4L, 5L, 9L, 1L, 9L, 12L, 6L, 0L, 7L, 8L, 6L, 4L, 4L), NotasMateriais...7. = c(3L, 
8L, 7L, 5L, 5L, 3L, 12L, 0L, 24L, 1L, 1L, 6L, 0L, 7L, 4L, 5L, 
9L, 0L, 3L, 8L, 2L, 8L, 12L, 4L, 0L, 5L, 8L, 5L, 0L, 1L), NotasMateriais...8. = c(0L, 
6L, 4L, 1L, 3L, 5L, 8L, 1L, 24L, 8L, 0L, 3L, 0L, 8L, 0L, 1L, 
6L, 0L, 2L, 2L, 1L, 2L, 13L, 1L, 0L, 9L, 4L, 7L, 1L, 1L), NotasMateriais...9. = c(0L, 
0L, 6L, 2L, 1L, 3L, 4L, 0L, 16L, 1L, 0L, 3L, 2L, 4L, 3L, 0L, 
2L, 1L, 0L, 7L, 0L, 2L, 10L, 1L, 1L, 7L, 5L, 2L, 0L, 2L), NotasMateriais...10. = c(0L, 
2L, 4L, 1L, 4L, 5L, 11L, 4L, 10L, 3L, 0L, 2L, 0L, 3L, 0L, 1L, 
3L, 0L, 1L, 5L, 1L, 2L, 9L, 2L, 0L, 3L, 7L, 3L, 0L, 0L), NotasMateriais...11. = c(4L, 
0L, 2L, 0L, 1L, 2L, 2L, 3L, 3L, 0L, 0L, 0L, 2L, 2L, 1L, 0L, 5L, 
0L, 0L, 2L, 0L, 0L, 4L, 2L, 0L, 3L, 3L, 2L, 0L, 0L), NotasMateriais...12. = c(6L, 
2L, 2L, 4L, 1L, 2L, 3L, 2L, 10L, 7L, 1L, 4L, 2L, 5L, 1L, 2L, 
5L, 0L, 0L, 0L, 0L, 3L, 6L, 2L, 2L, 6L, 2L, 3L, 2L, 1L), NotasMateriais...13. = c(1L, 
0L, 0L, 2L, 3L, 2L, 4L, 0L, 6L, 2L, 0L, 1L, 1L, 2L, 2L, 4L, 2L, 
0L, 0L, 2L, 0L, 1L, 4L, 0L, 0L, 4L, 1L, 1L, 2L, 0L)), .Names = c("NotasMateriais...4.", 
"NotasMateriais...5.", "NotasMateriais...6.", "NotasMateriais...7.", 
"NotasMateriais...8.", "NotasMateriais...9.", "NotasMateriais...10.", 
"NotasMateriais...11.", "NotasMateriais...12.", "NotasMateriais...13."
), row.names = c(NA, -30L), class = "data.frame")

I’m generating the following boxplot:

cores <- brewer.pal(10, "Dark2")
boxplot(dfMateriaisEstudo,
    main="Exibições de Páginas dos Materiais de Estudo",
    ylim=c(0,28),
    xlab="Material de Estudo",
    ylab="Exibições de Páginas",
    col=cores
    )

1. I need to put on the x axis the names: 01, 02, 03...to 10.
2. On the y axis I need the scale to be 1 in 1.
3. Would it be possible to enter a grid? So that the values of the y scale are easier to visualize.

Answer 1

Does the following serve? First plot an empty graph, just to define the limits on the axes x and y. Then comes the real graph.
Note the arguments axes = FALSE and add = TRUE at the end of boxplot.

cores <- RColorBrewer::brewer.pal(10, "Dark2")
plot(1, type = "n", xlim = c(0, ncol(dfMateriaisEstudo) + 1),
                 ylim = range(dfMateriaisEstudo),
                 axes = FALSE, xlab = "", ylab = "")

grid()
boxplot(dfMateriaisEstudo,
        main="Exibições de Páginas dos Materiais de Estudo",
        ylim=c(0,28),
        xlab="Material de Estudo",
        ylab="Exibições de Páginas",
        col=cores,
        axes = FALSE,
        add = TRUE
        )
axis(1, at = 1:10, labels = sprintf("%02d", 1:10))
axis(2, at = 0:25, labels = 0:25)