In trying to tweak the output of geom_bar(), I come across some solutions that include function(x) as here where the x-axis labels get wrapped by use of stringr:

scale_x_discrete(labels = function(x) str_wrap(x, width = 10))  

What exactly is function(x) doing? It is simply saying that it's followed by a function to apply to x? But then what's x exactly, since it's the data defined in the original ggplot aes call, while here it's the label text?

Just when I think I understand something in R...

TIA.

CodePudding user response：

The entire expression goes together

function(x) str_wrap(x, width = 10)

is an anonymous function in R (a function with no name). The labels= parameter of scale_x_discrete can take a vector of characters, or a function. If a function, ggplot will pass in the default breaks as input It doesn't have to be named "x", you can call it whatever you want. So this would work as well

scale_x_discrete(labels = function(default_breaks) str_wrap(default_breaks, width = 10))  

This is documented on the ?ggplot2::scale_x_discrete help page.