有没有办法在 fviz_eig 图中添加一个 cum sum？

Question

我正在尝试实现一个漂亮的 PC 图以及解释的累积方差。 我正在处理的数据框位于https://www.kaggle.com/miroslavsabo/young-people-survey?select=responses.csv

df.responses <- read.csv("Data/responses.csv")
pref <- colnames(df.responses[0:63]) #columns for Music, Movies and Hobbies preferences
for(i in 1:length(pref)){
  df.responses[is.na(df.responses[,i]), i] <- median(df.responses[,i], na.rm = TRUE)
}
df.movies <- data.frame(df.responses[20:31])

上面我刚刚加载了 df，删除了我感兴趣的 cols 的 na 并选择了我想要 PCA 的子集。

library(ggplot2)
library(factoextra)

pca.movies <- prcomp(df.movies, scale = TRUE,)
pca.movies$rotation <- -pca.movies$rotation
pca.movies$x <- -pca.movies$x

fviz_pca_var(pca.movies,
             col.var = "contrib",
             gradient.cols = c("#00AFBB", "#E7B800", "#FC4E07"),
             repel = TRUE   
)

pv.movies <- pca.movies$sdev^2 
pvp.movies <- pv.movies/sum(pv.movies)

pvp.movies

fviz_eig(pca.movies,
         addlabels = T, 
         barcolor = "#E7B800", 
         barfill = "#E7B800", 
         linecolor = "#00AFBB", 
         choice = "variance", 
         ylim=c(0,25))

plot(cumsum(pvp.movies),xlab = "Cumulative proportion of Variance Explained", ylim=c(0,1),type = 'b') 

通过以上方法，我设法为 PCA 获得了两个不错的图，我想在第二个图中添加累积和线（第三个丑图中显示的那个） 有没有办法将这样的线添加到 fviz_eig 图中？ 我知道这个 PCA 效率不高，我只是在用一些 dataviz 挑战自己。

Answer 1

fviz_eig 返回的对象是ggplot 对象，因此您可以将两个绘图合并如下：

p <- fviz_eig(pca.movies,
         addlabels = T, 
         barcolor = "#E7B800", 
         barfill = "#E7B800", 
         linecolor = "#00AFBB", 
         choice = "variance", 
         ylim=c(0,25))

df <- data.frame(x=1:length(pvp.movies),
                 y=cumsum(pvp.movies)*100/4)
p <- p + 
     geom_point(data=df, aes(x, y), size=2, color="#00AFBB") +
     geom_line(data=df, aes(x, y), color="#00AFBB") +
     scale_y_continuous(sec.axis = sec_axis(~ . * 4, 
                                   name = "Cumulative proportion of Variance Explained") )
print(p)