Question

有没有人知道是否有办法在GGally中为ggparcoord函数添加变量标签？我用geom_text尝试了很多方法，但没有任何结果。

为了更明确，我希望将row.names(mtcars)传递给geom_text。我可以区分汽车的唯一方法是通过row.names(mtcars)参数传递groupColumn，但我不喜欢它的外观。

不起作用：

mtcars$carName <- row.names(mtcars) # This becomes column 12
library(GGally)
# Attempt 1
ggparcoord(mtcars, 
           columns = c(12, 1, 6), 
           groupColumn = 1) +
geom_text(aes(label = carName))

# Attempt 2
ggparcoord(mtcars, 
           columns = c(12, 1, 6),
           groupColumn = 1,
           mapping = aes(label = carName))

任何想法都将不胜感激！

Answer 1

解决方案1 ：如果您想坚持原始尝试，则可以为汽车名称计算适当的y坐标，并将其添加为单独的数据源。使用inherit.aes = FALSE，以便此geom_text层不会继承使用ggparcoord()创建的ggplot对象的任何内容：

library(dplyr)

p1 <- ggparcoord(mtcars, 
                 columns = c(12, 1, 6), 
                 groupColumn = 1) +

  geom_text(data = mtcars %>%
              select(carName) %>%
              mutate(x = 1,
                     y = scale(as.integer(factor(carName)))),
            aes(x = x, y = y, label = carName),
            hjust = 1.1,
            inherit.aes = FALSE) +

  # optional: remove "carName" from x-axis labels
  scale_x_discrete(labels = function(x) c("", x[-1])) + 

  # also optional: hide legend, which doesn't really seem relevant here
  theme(legend.position = "none")
p1

解决方案2 ：该替代方法使用carName作为组列，并且不将其作为平行坐标列之一传递。（我认为这可能更接近于此功能预期的用例...）将carName指定为group列可将汽车名称值捕获在{{创建的ggplot对象的data}插槽中1}}，因此我们的ggparcoord()标签可以直接继承它，甚至仅过滤对应于geom_text的行（或在实际使用情况下命名的任何平行坐标列的第一行））。 y坐标没有像上面那样均匀分布，但是ggrepel软件包中的variable == "mpg"在将重叠的文本标签彼此移开方面做得不错。

geom_text_repel

解决方案3/4 ：您实际上可以使用library(dplyr) library(ggrepel) p2 <- ggparcoord(mtcars, columns = c(1, 6), groupColumn = "carName") + geom_text_repel(data = . %>% filter(variable == "mpg"), aes(x = variable, y = value, label = carName), xlim = c(NA, 1)) + # limit repel region to the left of the 1st column theme(legend.position = "none") # as before, hide legend since the labels # are already in the plot p2绘制相同内容，而不必依赖于可能在幕后做意外事情的扩展程序：

ggplot()

修改

对于以上每个选项，您也可以在右侧添加文本标签。请注意，标签的位置可能没有很好地隔开，因为它们是根据library(dplyr) library(tidyr) library(ggrepel) # similar output to solution 1 p3 <- mtcars %>% select(carName, mpg, wt) %>% mutate(carName.column = as.integer(factor(carName))) %>% gather(variable, value, -carName) %>% group_by(variable) %>% mutate(value = scale(value)) %>% ungroup() %>% ggplot(aes(x = variable, y = value, label = carName, group = carName)) + geom_line() + geom_text(data = . %>% filter(variable == "carName.column"), hjust = 1.1) + scale_x_discrete(labels = function(x) c("", x[-1])) p3 # similar output to solution 2 p4 <- mtcars %>% select(carName, mpg, wt) %>% gather(variable, value, -carName) %>% group_by(variable) %>% mutate(value = scale(value)) %>% ungroup() %>% ggplot(aes(x = variable, y = value, label = carName, group = carName)) + geom_line() + geom_text_repel(data = . %>% filter(variable == "mpg"), xlim = c(NA, 1)) p4的缩放值进行定位的：

wt

ggplot / GGally - 平行坐标 - y轴标签

1 个答案: