使用ggplot2的多个条形图

Question

根据this示例，我尝试绘制以下内容

数据集如下：

df <- structure(list(year = 2002:2005, work = c(1L, 2L, 3L, 2L), confid = c(8L, 
5L, 0L, 6L), jrs = c(0L, 3L, 4L, 5L)), .Names = c("year", "work", 
"confid", "jrs"), class = "data.frame", row.names = c(NA, -4L
))

为了绘制代码：

library(ggplot2)
library(reshape)
md <- melt(df, id=(c("year")))
temp.plot<-ggplot(data=md, aes(x=year, y=value, fill=variable) ) + 
    geom_bar()+ opts(axis.text.x=theme_text(angle=90)) + 
    opts(title = "Score Distribtion")

我收到错误：

Error: could not find function "opts"

我试图从图中删除opts（），但我又收到同样的错误。

这可能是什么问题？

Answer 1

代码的更新版本使用theme代替opts：

df <- structure(list(year = 2002:2005, work = c(1L, 2L, 3L, 2L), confid = c(8L, 
5L, 0L, 6L), jrs = c(0L, 3L, 4L, 5L)), .Names = c("year", "work", 
"confid", "jrs"), class = "data.frame", row.names = c(NA, -4L
))

library(ggplot2)
library(reshape)
md <- melt(df, id=(c("year")))
temp.plot <- ggplot(data=md, aes(x=year, y=value, fill=variable) ) + 
    geom_bar(stat="identity")+ 
    theme(axis.text.x=element_text(angle=90))+ 
    ggtitle("Score Distribtion")

temp.plot