R – ordering in boxplot

by

The following commands will create the ordering you need by rebuilding the Treatment and Species factors, with explicit manual ordering of the levels:

mydata$Treatment = factor(mydata$Treatment,c("L","M","H"))

mydata$Species = factor(mydata$Species,c("G","R","B"))

alt text

edit 1 : oops I had set it to HML instead of LMH. fixing.

edit 2 : what factor(X,Y) does:

If you run factor(X,Y) on an existing factor, it uses the ordering of the values in Y to enumerate the values present in the factor X. Here’s some examples with your data.

> mydata$Treatment
[1] L M H L M H
Levels: H L M
> as.integer(mydata$Treatment)
[1] 2 3 1 2 3 1
> factor(mydata$Treatment,c("L","M","H"))
[1] L M H L M H                               <-- not changed
Levels: L M H                                 <-- changed
> as.integer(factor(mydata$Treatment,c("L","M","H")))
[1] 1 2 3 1 2 3                               <-- changed

It does NOT change what the factor looks like at first glance, but it does change how the data is stored.

What’s important here is that many plot functions will plot the lowest enumeration leftmost, followed by the next, etc.

If you create factors simply using factor(X) then usually the enumeration is based upon the alphabetical order of the factor levels, (e.g. “H”,”L”,”M”). If your labels have a conventional ordering different from alphabetical (i.e. “H”,”M”,”L”), this can make your graphs seems strange.

At first glance, it may seem like the problem is due to the ordering of data in the data frame – i.e. if only we could place all “H” at the top and “L” at the bottom, then it would work. It doesn’t. But if you want your labels to appear in the same order as the first occurrence in the data, you can use this form:

 mydata$Treatment = factor(mydata$Treatment, unique(mydata$Treatment))

More Related Contents:

  1. Plot multiple boxplot in one graph
  2. Put stars on ggplot barplots and boxplots – to indicate the level of significance (p-value)
  3. Labeling Outliers of Boxplots in R
  4. Changing whisker definition in geom_boxplot
  5. Merge and Perfectly Align Histogram and Boxplot using ggplot2
  6. How to add a number of observations per group and use group mean in ggplot2 boxplot?
  7. How to change order of boxplots when using ggplot2?
  8. How to plot a hybrid boxplot: half boxplot with jitter points on the other half?
  9. geom_boxplot with precomputed values
  10. Include space for missing factor level used in fill aesthetics in geom_boxplot
  11. How to create a grouped boxplot in R?
  12. In ggplot2, what do the end of the boxplot lines represent?
  13. Removing one tableGrob when applied to a box plot with a facet_wrap
  14. How to draw the boxplot with significant level?
  15. For the same code, labels (q1, median) appear on one computer but don’t appear on another computer
  16. Joining means on a boxplot with a line (ggplot2)
  17. Generate ggplot2 boxplot with different colours for multiple groups
  18. Change or modify x axis tick labels in R using ggplot2 [duplicate]
  19. Add color to boxplot – “Continuous value supplied to discrete scale” error
  20. lower and upper quartiles in boxplot in R
  21. annotate boxplot in ggplot2
  22. Add number of observations per group in boxplot
  23. How to plot intersecting ranges in Excel/R/Matlab [closed]
  24. Remove columns from dataframe where ALL values are NA
  25. Overlaying histograms with ggplot2 in R
  26. how to create two independent drill down plot using Highcharter?
  27. pie chart with ggplot2 with specific order and percentage annotations
  28. Any way to force fread() of data.table not to stop on empty lines?
  29. displaying TRUE when shiny files are split into different folders
  30. how to create md5 hash of a column in R?

Leave a Comment