r - 将cut()产生的标签格式化为百分比

Question

我需要在连续变量上应用cut，以使其在ggplot2中以Brewer色标显示，如Setting breakpoints for data with scale_fill_brewer() function in ggplot2所示。连续变量是一个相对的差异，我想将数据格式设置为“ 18.2％”而不是“ 0.182”。有没有简单的方法可以做到这一点？

x <- runif(100)
levels(cut(x, breaks=10))

[1] "(0.0223,0.12]" "(0.12,0.218]"  "(0.218,0.315]" "(0.315,0.413]"
[5] "(0.413,0.511]" "(0.511,0.608]" "(0.608,0.706]" "(0.706,0.804]"
[9] "(0.804,0.901]" "(0.901,0.999]"

我想例如第一个级别显示为(2.23 %, 12 %]。有没有更好的替代方法？

Answer 1

我已经在cut_format()软件包的0.2-3版本中实现了kimisc，现在CRAN上的版本是0.3。

# devtools::install_github("krlmlr/kimisc")
x <- seq(0.1, 0.9, by = 0.2)

breaks <- seq(0, 1, by = 0.25)

cut(x, breaks)
## [1] (0,0.25]   (0.25,0.5] (0.25,0.5] (0.5,0.75] (0.75,1]  
## Levels: (0,0.25] (0.25,0.5] (0.5,0.75] (0.75,1]

cut_format(x, breaks, format_fun = scales::percent)
## [1] (0%, 25%]   (25%, 50%]  (25%, 50%]  (50%, 75%]  (75%, 100%]
## Levels: (0%, 25%] (25%, 50%] (50%, 75%] (75%, 100%]

它仍然不是完美的，无法传递中断数（如原始示例中所示）。