R ggplot coord_cartesian(ylim()) vs ylim()
Former is limited to plot display only, while the latter is on the analysis result.
Let's use boxplot as an example.
require("ggplot2")
## Loading required package: ggplot2
## Warning: package 'ggplot2' was built under R version 3.0.3
df = data.frame(y = c(0, 50, 100, 501, 600))
median(df$y)
## [1] 100
p <- ggplot(df, aes(y = y)) + geom_boxplot(aes(x = factor(1)))
coord_cartesian(ylim) will
- analyze the entire dataset to produce the plot
- then, limit the plot to the range specified
p + coord_cartesian(ylim = c(0, 200))
ylim alone will
- limit the data set within the range
- then, analyze the leftover to produce the plot
p + ylim(c(0, 200))
## Warning: Removed 2 rows containing non-finite values (stat_boxplot).
as shown above,
- the warning tells you that 2 rows were left out, and
- the median with ylim alone is 50, rather 100.
