使用ggplot2 - R的geom_bar（）查询

Question

我有类似的数据框如下：

mapDF <- structure(list(var = c(11L, 3L, 4L, 15L, 19L, 17L, 1L), approvals = c(10.5233545765422, 
67.9809421770218, 9.66394835013545, 2.93736399165075, 3.36787205222721, 
4.0168261757783, 1.50969267664431)), .Names = c("var", "approvals"
), row.names = c(NA, -7L), class = "data.frame")

当我尝试使用上面的数据框创建条形图时使用：

gplot <- ggplot(mapDF, aes(x= mapDF[1], y= mapDF[2])) + geom_bar()

..我收到以下消息，其中没有出现在RStudio的'Plots'部分中：

Don't know how to automatically pick scale for object of type data.frame. Defaulting to continuous
Don't know how to automatically pick scale for object of type data.frame. Defaulting to continuous
Error: stat_bin requires the following missing aesthetics: x

任何人都可以指出我的错误吗？

Answer 1

滚动@joran的评论回答：

ggplot(mapDF, aes(x=var, y=approvals)) + geom_bar(stat="identity")