如何控制条形图中值标签的小数位

Question

考虑下图：

这个问题是关于如何将堆叠条形图中的所有值标签保留一位小数，以保持一致性。因此，将-1、2和5表示为-1.0、2.0和5.0与其他一致。这是一个示例数据

df  <- data.frame(group=c("satisfied", "satisfied",
                      "unsatisfied","unsatisfied",
                      "satisfied", "satisfied", 
                      "unsatisfied","unsatisfied"
                      ), 
                cost=c("low","high","low","high",
                      "low","high","low","high"),     
                treatment=c("treated","treated","treated","treated",
                            "untreated","untreated",
                      "untreated","untreated") ,
                value=c(2.3,8.7,5.0,3.1,9.4,3.1,2.0,-1.0)) 

生成图形的代码是

#REORDER
df$group <- factor(df$group, levels = c("satisfied", 
                            "unsatisfied"))

ggplot(data=df,aes(y = value, x = group, fill = cost)) +
geom_bar(stat="identity",position='stack') + 
ylab("Y label") +
theme(legend.direction = "horizontal",legend.position = "bottom",
    legend.spacing.x = unit(0.1, 'cm'))+
theme(legend.title=element_blank())+
geom_text(aes(label = ifelse(value !=0, value, "")), 
         position = position_stack(vjust=0.5))+
facet_grid( ~ treatment)

在 之后，我试图通过引入

来解决这个问题

sprintf("%0.1f", round(value, digits = 2))

进入 ggplot 函数，但这不会产生所需的输出。我非常感谢对此的任何帮助。

Answer 1

问题是您使用 sprintf 在 之前 舍入（并因此转换为 character，丢失数字信息）。要格式化数字，您需要提供 sprintf 个数字，而不是字符串。它将自行处理舍入。试试这个：

label = ifelse(value !=0, sprintf("%0.1f", value), "")

制作整个代码：

ggplot(data = df, aes(y = value, x = group, fill = cost)) +
  geom_bar(stat = "identity", position = 'stack') +
  ylab("Y label") +
  theme(
    legend.direction = "horizontal",
    legend.position = "bottom",
    legend.spacing.x = unit(0.1, 'cm')
  ) +
  theme(legend.title = element_blank()) +
  geom_text(aes(label = ifelse(value !=0, sprintf("%0.1f", value), "")),
            position = position_stack(vjust = 0.5)) +
  facet_grid(~ treatment)

---

由于ifelse，上面的内容有点奇怪。更标准的 ggplot2 解决方案会让您以另一种方式摆脱 0 - 也许在绘图之前将其过滤掉，将 data = filter(df, y != 0) 提供给 ggplot()。然后你可以使用scales函数

label = scales::label_number(accuracy = 0.1)(value)

整个代码如下，结果相同：

ggplot(data = dplyr::filter(df, value != 0), aes(y = value, x = group, fill = cost)) +
  geom_bar(stat = "identity", position = 'stack') +
  ylab("Y label") +
  theme(
    legend.direction = "horizontal",
    legend.position = "bottom",
    legend.spacing.x = unit(0.1, 'cm')
  ) +
  theme(legend.title = element_blank()) +
  geom_text(aes(label = scales::label_number(accuracy = 0.1)(value)),
            position = position_stack(vjust = 0.5)) +
  facet_grid(~ treatment)