r - 在 R 中绘制两个条形图

Question

 data <- as.matrix(data.frame("A" = c(18,7),
                                "B+" = c(3,2),
                                "B" = c(3,3),
                                "C+" = c(6,0),
                                "C" = c(7,0),
                                "D" = c(0,4),
                                "E" = c(5,23)))
    
    
    barplot (data,
            col = c("red","blue"),
            beside = TRUE,
            xlab = "Grade",
            ylab = "Frequency")
    
    
    legend("topleft",
           c("IFC6503-A","IFC6510"),
           fill = c("red","blue"),
           inset = c(.01,0)
    )

我将两个条形图绘制在一起，条形图包含等级，来自两个不同的数据，等级由 A B+ B C+ CDE ，但结果 B+ 和 C+ 没有出现，只出现 B. 和 C. ，是我的代码错误或者你们能更正我的代码吗？

Answer 1

不要使用特殊字符 +在伯恩哈德已经指出的列名中:
这是一种您可以手动重新标记绘图的 x 轴的方法:

在您的矩阵中提供足够的列名:请参阅 whuber 的评论:https://stats.stackexchange.com/questions/163280/naming-convention-for-column-names

使用 xaxt = "n"在条形图中删除 x 个标签

使用 axis手动插入 x 个标签:

data <- as.matrix(data.frame("A" = c(18,7),
                             "Bplus" = c(3,2),
                             "B" = c(3,3),
                             "Cplus" = c(6,0),
                             "C" = c(7,0),
                             "D" = c(0,4),
                             "E" = c(5,23)))


barplot (data,
         col = c("red","blue"),
         beside = TRUE,
         xlab = "Grade",
         ylab = "Frequency",
         xaxt = "n")
         
axis(1, at = seq(2, 20, 3), labels = c("A", "B+", "B", "C+", "C", "D", "E"))


legend("topleft",
       c("IFC6503-A","IFC6510"),
       fill = c("red","blue"),
       inset = c(.01,0)
)