Joyce Robbins Oct 2, 2021

ggformat

This is a one function addin package. My motivation in writing it was to make it easier to clean up and style ggplot2 code.

Note: this is new – please report bugs or leave comments!

Installation

remotes::install_github("jtr13/ggformat")

Usage

Highlight code thats produce a single ggplot2 graph, run the addin “Format ggplot2 code”, and the code will be cleaned up and styled. For example,

# BEFORE
mtcars %>% group_by(cyl) %>% summarize(mean_mpg = mean(mpg)) %>% ggplot(aes(factor(cyl),
mean_mpg)) + theme_bw(14) + geom_col() + xlab("number of cylinders") +
ylab("average miles per gallon") + ggtitle("mtcars")

will become:

# AFTER
mtcars %>%
  group_by(cyl) %>%
  summarize(mean_mpg = mean(mpg)) %>%
  ggplot(aes(factor(cyl), mean_mpg)) +
  geom_col() +
  ggtitle("mtcars") +
  xlab("number of cylinders") +
  ylab("average miles per gallon") +
  theme_bw(14)

What the styled code looks like

• %>%s are followed by line breaks

• Each ggplot2 function appears on its own line followed by a +. Misplaced +s, such as after the last function, are removed.

• ggplot2 functions are sorted based on the ggplot2 template:

Labeling functions (ggtitle, labs, xlab, ylab, annotate) are placed between scales and themes. Guides are added between labeling functions and themes.

Source: https://github.com/rstudio/cheatsheets/raw/master/data-visualization.pdf

The specific sort order is:

##  [1] "%>%"      "ggplot"   "geom_"    "stat_"    "coord_"   "facet_"  
##  [7] "scale_"   "xlim"     "ylim"     "ggtitle"  "labs"     "xlab"    
## [13] "ylab"     "annotate" "guides"   "theme_"   "theme"

• If there are multiple instances of a function type, for example, multiple geoms, the current order is preserved.

• You can easily set your own sort order by forking the project and changing the splitwords variable in ggformat.R.

How it differs from other formatting packages

• THE BIG DIFFERENCE: Neither formatR nor styler change the order of ggplot2 functions.

• formatR does not add line breaks after +s in ggplot2 code.

• styler reformats long lines by putting each argument on its own line and indenting, for example:

ggplot() +
    geom_ribbon(data = ribbon, aes(
        ymin = min,
        ymax = max,
        x = x.ribbon,
        fill = 'lightgreen'
    )) +
    geom_line(data = ribbon, aes(x = x.ribbon, y = avg, color = 'black')) +
    geom_line(data = data, aes(x = x, y = new.data, color = 'red')) +
    scale_fill_identity(name = 'the fill',
                        guide = 'legend',
                        labels = c('m1')) +
    scale_colour_manual(
        name = 'the colour',
        values = c('black' = 'black', 'red' = 'red'),
        labels = c('c2', 'c1')
    ) +
    xlab('x') +
    ylab('density')

ggformat styles this code as:

ggplot() +
  geom_ribbon(data = ribbon, aes(ymin = min, ymax = max, x = x.ribbon, fill = 'lightgreen')) +
  geom_line(data = ribbon, aes(x = x.ribbon, y = avg, color = 'black')) +
  geom_line(data = data, aes(x = x, y = new.data, color = 'red')) +
  scale_fill_identity(name = 'the fill', guide = 'legend', labels = c('m1')) +
  scale_colour_manual(name = 'the colour', values = c('black' = 'black', 'red' = 'red'), labels = c('c2', 'c1')) +
  xlab('x') +
  ylab('density')

Note: I hope to add wrapping so long lines are broken apart after commas:

# NOT YET IMPLEMENTED
ggplot() +
  geom_ribbon(data = ribbon, aes(ymin = min, ymax = max, x = x.ribbon, fill = 'lightgreen')) +
  geom_line(data = ribbon, aes(x = x.ribbon, y = avg, color = 'black')) +
  geom_line(data = data, aes(x = x, y = new.data, color = 'red')) +
  scale_fill_identity(name = 'the fill', guide = 'legend', labels = c('m1')) +
  scale_colour_manual(name = 'the colour', values = c('black' = 'black', 'red' = 'red'),
    labels = c('c2', 'c1')) +
  xlab('x') +
  ylab('density')

Nitty Gritty

• +’s are cleaned up so there is exactly one + at the end of every line except the last, and lines ending in pipes. Specifically, double +’s are replaced with single +’s, +’s before special ggplot2 words are removed, +’s are added back at the ends of lines.

Known issues

• Doesn’t wrap long lines

• Can’t handle package namespacing such as ggalluvial::geom_flow()

• Can’t handle comments (puts them before +)

I welcome your suggestions for improvements.

Acknowledgements

The blog post “strsplit – but keeping the delimiter” by Jakob Gepp was helpful for formulating strsplit() splits that keep the search terms.