R ggpairs 更改對角線上條形直方圖的顏色

Question

我想更改成對圖上直方圖條形的顏色，從而為每個變量設置不同的顏色。 看來我可以通過將 'fill =' 選項更改為新顏色來更改所有對角直方圖的顏色，但是當我嘗試替換四種顏色的列表時，我收到錯誤報告：

“r：美學必須是長度為1或與數據相同（15）：填充”

因此，顏色似乎以某種方式與為直方圖指定的 bin 數量而不是每個直方圖的填充顏色相關聯？

為對角線上的每個直方圖實現不同顏色的最佳方法是什么？

示例代碼如下：

require(GGally)

# function for scatter plots with smoothed trend line
lower_plots <- function(data, mapping, ...) {
  ggplot(data = data, mapping = mapping) +
    geom_point(color = "black", shape = 1, size = 1, alpha = 1) +
    geom_smooth(method = "gam",...) 
} 

# colour palette for histograms - subsitue for fill = ?
clrs <- c("red","green","blue","orange")

# pairs plot
ggpairs(iris,1:4, 
        diag = list(continuous = wrap("barDiag", bins = 15, fill = "blue")),
        lower = list(continuous = wrap(lower_plots, color="red", se=F))) +
  theme_light(base_size = 12) +                                                                                                                 
  theme_light(base_size = 12) +                                                                                                                 
  scale_fill_manual(values = ZNS[order(ZNS$Zone), 4])  +                                                                                         
  theme(panel.grid.minor = element_blank(), panel.grid.major = element_blank()) +
  theme(plot.margin = unit(c(2.5,2.5,2.5,3.5), "lines")
  ) 

Answer 1

我通過在函數內部使用全局賦值找到了解決您問題的方法。 首先，我認為這是不可能的，因為缺乏能夠在輸入的一列中識別如何為直方圖着色，因為每行都包含多個觀察結果......我測試了一下並想知道，考慮到一切的事實分批/循環處理，全局分配會有所幫助 - 它確實：

require(GGally)

# function for scatter plots with smoothed trend line
lower_plots <- function(data, mapping, ...) {
    ggplot(data = data, mapping = mapping) +
        geom_point(color = "black", shape = 1, size = 1, alpha = 1) +
        geom_smooth(method = "gam",...) 
} 

# working with a trick of global assignment
diag_plots <- function(data, mapping, ...) {
    # increase counter each run globally so outside the function as well and this does the trick!
    x <<- x + 1
    ggplot(data = data, mapping = mapping) +
        # choose color by counter and send bin width argument in
        geom_histogram(fill = clrs[x], ...)
} 

# set the color and counter
clrs <- c("red","green","blue","orange")
x <- 0

# pairs plot
ggpairs(iris,1:4, 
        diag = list(continuous = wrap(diag_plots, bins = 15)),
        lower = list(continuous = wrap(lower_plots, color="red", se=FALSE))) +
        theme_light(base_size = 12) + 
        theme_light(base_size = 12) + 
        theme(panel.grid.minor = element_blank(), panel.grid.major = element_blank()) +
    theme(plot.margin = unit(c(2.5,2.5,2.5,3.5), "lines"))