使用ggcorrplot包更改相关图的对角线方向-如果类型为"upper“或"lower”

Question

我有一个关于one here的后续问题。

这个人想用ggcorrplot包中的ggcorrplot绘制相关图。然而，他们想让对角线沿着矩阵而不是从左到右向上移动。因此，他们想让图表看起来像他们用作输入的相关矩阵：

library(ggcorrplot)
data(mtcars)
corr.mat <- cor(mtcars[, c("mpg", "disp", "hp", "drat", "wt", "carb")])
ggcorrplot(corr.mat)
print(corr.mat)

给出了以下解决方案，只要您使用规范type = "full“，就可以很好地工作。然而，如果你只想显示一半的图形，它就会变得混乱：

# This suggested solution works fine:
ggcorrplot(corr.mat[,6:1])
# The same: 
ggcorrplot(corr.mat[,6:1], type = "full")

# Here we have the problem:
ggcorrplot(corr.mat[,6:1], type = "upper")

有人知道如何制作从左上角到右下角的对角线上的相关图吗？

Answer 1

您可以使用geom_tile手动绘制corr.mat：

library(data.table)
library(ggplot2)
cordt <- as.data.table(corr.mat, keep.rownames = 'col_name')
cordt <- melt(cordt, id.vars = 'col_name', variable.name = 'row_name')

# convert to factor so that rows and columns have the same order as the data
cordt[, row_name := factor(row_name, levels = rev(rownames(corr.mat)))]
cordt[, col_name := factor(col_name, levels = rownames(corr.mat))]

# set diagonal and the top-right half of the matrix to 0 so that those cells appears white
cordt[ncol(corr.mat) - as.integer(row_name) < as.integer(col_name), value := 0]
# remove the last column and the bottom row (where left cells are self correlations only)
cordt <- cordt[as.integer(row_name) < ncol(corr.mat) &
        as.integer(col_name) < ncol(corr.mat)]

ggplot(cordt, aes(x = col_name, y = row_name, fill = value)) +
    geom_tile() +
    scale_fill_gradient2(low = 'blue', high = 'red') +
    labs(x = NULL, y = NULL, fill = 'Corr') +
    theme_minimal()

​

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Answer 2

当我只想显示相关矩阵的一半时，我使用这个(来自GGally包)：

ggcorr(mtcars[, c("mpg", "disp", "hp", "drat", "wt", "carb")], method = c('everything', "p"))

然而，对角线并不是你想要的。也许有一个选项可以反转它。