ggplot2 绘图 x轴标签顺序

x <- c("B","A","D","C","E")                                 ## 测试数据顺序
y <- c(5,6,7,8,9)
df <- data.frame(x = x , y = y)
df

library("ggplot2")
ggplot(data=df,aes(x=x,y=y)) + geom_bar(stat="identity")      ## ggplot2自动排序

## 调整因子水平
df$x <- factor(df$x,levels=c("B","A","D","C","E"))
## 绘制条形图
ggplot(data=df,aes(x=x,y=y)) + geom_bar(stat="identity")       ## 按照指定顺序输出