使用aes_string时，格式化geom_text标签不起作用 [英] Format geom_text label doesn't work when using aes_string

问题描述

我正在使用点函数来格式化用ggplot2创建的绘图中的文本标签.使用aes时，此方法工作正常，但使用aes_string时，效果不佳.是否有一种变通办法可以使其与aes_string一起使用?

I am using the dot function to format text labels in a plot created with ggplot2. This works fine when using aes, but doesn't work like expected when using aes_string. Is there a workaround to make it work with aes_string?

require(ggplot2)

# Define the format function
dot <- function(x, ...) { 
  format(x, ..., big.mark = ".", scientific = FALSE, trim = TRUE)
}

# Create dummy data
df <- data.frame(cbind(levels(iris$Species),c(10000000000,200000,30000)))
df$X2 <- as.numeric(as.character(df$X2))

# Works with aes   
ggplot(iris) + 
  geom_bar(aes(Species,Sepal.Width),stat="identity") +     
  geom_text(data=df,aes(x=factor(X1),y=180,label=dot(X2)))


# Doesn't work with aes_string
ggplot(iris) + 
  geom_bar(aes(Species,Sepal.Width),stat="identity") +
  geom_text(data=df,aes_string(x="X1",y=180,label=dot("X2")))

推荐答案

您不仅要引用"X2"，还必须引用整个表达式

Rather than just quote "X2", you must quote the whole expression

ggplot(iris) + 
  geom_bar(aes(Species, Sepal.Width), stat = "identity") + 
  geom_text(data=df, aes_string(x="X1", y =180, label = "dot(X2)"))

如果要通过字符向量指定变量名，则可以使用paste()来构建该表达式.

If you wanted to specify variable names via a character vector, you would use paste() to build that expression.

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