有人能告诉我为什么我一直收到这个错误吗；mtcars$am中出现错误：$运算符对原子向量无效；？

我正在mtcars中使用vs和am数据集，并试图创建一个条形图，但这个错误对我来说不起作用：（我是新手，因此非常感谢您的帮助。

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谢谢！

在

表

之后的结束括号中有一个不匹配项。除了

图例

之外，还有一个单独的参数

barplot(table(mtcars$am, mtcars$vs, col = c("#b9c8fd", "#c8fdb9"),
xlab = "Transmission Type",ylab = "Frequency", 
ylim = c(0,25), names.arg = c("Automatic", "Manual"), 
legend("topright", legend = c("V Shaped Engines")), pch = (19:20), 
col = c("#b9c8fd", "#c8fdb9"), abline(h=0) ))

-输出

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谢谢您的建议！我做了上述更改，并修改了代码，使其内容如下：

barplot(table(mtcars$am, mtcars$vs), col = c("#b9c8fd", "#c8fdb9"), 
  xlab = "Transmission Type",ylab = "Frequency",  ylim = c(0,25), 
     names.arg = c("Automatic", "Manual"))
legend("topright", legend = c("V Shaped Engines"), pch = 19:20)

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它起作用了！

在

表格

之后，您忘记关闭

）

即

表格（mtcars$am，mtcars$vs）

barplot(table(vs,am), col = c("blue", "green"), 
xlab = "Transmission Type",
ylab = "Frequency",
ylim = c(0,25),
main = "Stacked Barplot...",
names.arg = c("Automatic", "Manual"),
axis.lty = 1, font.main = 4)

legend("topright", legend = c("Automatic", "Manual"), pch = 19:20,
col = c("blue", "green"))