r - 打印带有加号的正数

Question

我正在计算年份与引用年份之间的差额。我想将结果用作绘图中的x值。但是，如何打印带有正数(-2，-1、0，+ 1，+ 2)的+号呢？

dat <- data.frame(year = c(2000, 2001, 2002, 2003, 2004), ref = rep(2002)) 
dat$diff <- dat$year - dat$ref

ggplot(dat, aes(x = diff))

Answer 1

你可以做

library(ggplot2)
dat <- data.frame(year = c(2000, 2001, 2002, 2003, 2004), ref = rep(2002)) 
dat$diff <- dat$year - dat$ref
ggplot(dat, aes(x = diff)) + 
  scale_x_continuous(labels = function(x) sprintf("%+d", x))