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在ggplot2中的堆积条形图上显示数据值

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我想在ggplot2中的堆积条形图上显示数据值 . 这是我尝试过的代码

Year      <- c(rep(c("2006-07", "2007-08", "2008-09", "2009-10"), each = 4))
Category  <- c(rep(c("A", "B", "C", "D"), times = 4))
Frequency <- c(168, 259, 226, 340, 216, 431, 319, 368, 423, 645, 234, 685, 166, 467, 274, 251)
Data      <- data.frame(Year, Category, Frequency)
library(ggplot2)
p <- qplot(Year, Frequency, data = Data, geom = "bar", fill = Category,     theme_set(theme_bw()))
p + geom_text(aes(label = Frequency), size = 3, hjust = 0.5, vjust = 3, position =     "stack")

enter image description here

我想在每个部分的中间显示这些数据值 . 在这方面的任何帮助将受到高度赞赏 . 谢谢

2 回答

  • 131

    ggplot 2.2.0可以使用 geom_text 中的 position = position_stack(vjust = 0.5) 轻松堆叠标签 .

    ggplot(Data, aes(x = Year, y = Frequency, fill = Category, label = Frequency)) +
      geom_bar(stat = "identity") +
      geom_text(size = 3, position = position_stack(vjust = 0.5))
    

    enter image description here

    另请注意,“ position_stack()position_fill() 现在以分组的相反顺序堆栈值,这使得默认堆栈顺序与图例匹配 . ”


    答案对旧版本的 ggplot 有效:

    这是一种计算条形中点的方法 .

    library(ggplot2)
    library(plyr)
    
    # calculate midpoints of bars (simplified using comment by @DWin)
    Data <- ddply(Data, .(Year), 
       transform, pos = cumsum(Frequency) - (0.5 * Frequency)
    )
    
    # library(dplyr) ## If using dplyr... 
    # Data <- group_by(Data,Year) %>%
    #    mutate(pos = cumsum(Frequency) - (0.5 * Frequency))
    
    # plot bars and add text
    p <- ggplot(Data, aes(x = Year, y = Frequency)) +
         geom_bar(aes(fill = Category), stat="identity") +
         geom_text(aes(label = Frequency, y = pos), size = 3)
    

    Resultant chart

  • 17

    正如hadley所提到的,与堆积条形图中的标签相比,有更有效的方式来传达您的信息 . 事实上,堆积图表不是很有效,因为条形(每个类别)不共享轴,因此比较困难 .

    在这些实例中使用两个图形,共享一个公共轴几乎总是更好 . 在您的示例中,我假设您要显示总体总数,然后显示每个类别在给定年份中贡献的比例 .

    library(grid)
    library(gridExtra)
    library(plyr)
    
    # create a new column with proportions
    prop <- function(x) x/sum(x)
    Data <- ddply(Data,"Year",transform,Share=prop(Frequency))
    
    # create the component graphics
    totals <- ggplot(Data,aes(Year,Frequency)) + geom_bar(fill="darkseagreen",stat="identity") + 
      xlab("") + labs(title = "Frequency totals in given Year")
    proportion <- ggplot(Data, aes(x=Year,y=Share, group=Category, colour=Category)) 
    + geom_line() + scale_y_continuous(label=percent_format())+ theme(legend.position = "bottom") + 
      labs(title = "Proportion of total Frequency accounted by each Category in given Year")
    
    # bring them together
    grid.arrange(totals,proportion)
    

    这将为您提供如下所示的2面板显示:

    Vertically stacked 2 panel graphic

    如果要添加频率值,表格是最佳格式 .

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