Error “NAs are not allowed in subscripted assignments” while using Squash_axis in ggplot2, with dataset without NA-values

Question

I want to skip part of my y-axis for a dataset with most values between -10 and 100, and then a few at 400 again. So I want to squeeze this empty area. I already am using fa

Answer 1

Using browser() if figured out that the problem arises in the inv part of the squish transformation. But I could only guess what the reason is, probably has to do with how the breaks are set (??). However, instead of applying the transformation inside scale_y_continuous I tried applying it via coord_trans ... et voila, worked:

library(ggplot2)

dat <- data.frame(group=rep(c('A', 'B', 'C', 'D'), each = 10), 
                  value=c(rnorm(10), rnorm(10)+100)
)

squash_axis <- function(from, to, factor) { 
  # A transformation function that squashes the range of [from, to] by factor on a given axis 

  # Args:
  #   from: left end of the axis
  #   to: right end of the axis
  #   factor: the compression factor of the range [from, to]
  #
  # Returns:
  #   A transformation called "squash_axis", which is capsulated by trans_new() function

  trans <- function(x) {    
    # get indices for the relevant regions
    isq <- x > from & x < to
    ito <- x >= to

    # apply transformation
    x[isq] <- from + (x[isq] - from)/factor
    x[ito] <- from + (to - from)/factor + (x[ito] - to)

    return(x)
  }

  inv <- function(x) {

    # get indices for the relevant regions
    isq <- x > from & x < from + (to - from)/factor
    ito <- x >= from + (to - from)/factor

    # apply transformation
    x[isq] <- from + (x[isq] - from) * factor
    x[ito] <- to + (x[ito] - (from + (to - from)/factor))

    return(x)
  }

  # return the transformation
  return(scales::trans_new("squash_axis", trans, inv, domain = c(from, to)))
}

ggplot(dat,aes(x=group, y = value))+
  geom_point()+
  coord_trans(y = squash_axis(5, 95, 10))

^{Created on 2020-04-03 by the reprex package (v0.3.0)}