使用whichAreBijection命令从使用r的dataPreparation包中自动从数据帧中删除双射列

Question

我在做一个简单的任务时遇到了困难：

假设我使用这些库并拥有以下数据框架：

library(tidyverse)
library(dataPreparation)

df <- data.frame(col1 = 1, col2 = rnorm(1e1), col3 = sample(c(1, 2), 1e1, replace = TRUE))
df$col4 <- df$col2
df$col5[df$col3 == 1] = "a"
df$col5[df$col3 == 2] = "b"
df$col6 = c("b","b","a","a","b","a","a","a","a","b")
df$col7 = "d"
df$col8 = c(3,3,5,5,3,5,5,5,5,3)
df$col9 = c("x","x","y","y","x","y","y","y","y","x")
df$col10 = c("p","p","q","p","q","q","p","p","q","q")
df$col11 = c(10.5,10.5,11.37,10.5,11.37,11.37,10.5,10.5,11.37,11.37)
df <- df %>% mutate_if(is.character,as.factor)

使用下面的命令，我希望从df中删除列4、5、7、8、9、11。

whichAreBijection(df)
[1] "whichAreBijection: col7 is a bijection of col1. I put it in drop list."
[1] "whichAreBijection: col4 is a bijection of col2. I put it in drop list."
[1] "whichAreBijection: col5 is a bijection of col3. I put it in drop list."
[1] "whichAreBijection: col8 is a bijection of col6. I put it in drop list."
[1] "whichAreBijection: col9 is a bijection of col6. I put it in drop list."
[1] "whichAreBijection: col11 is a bijection of col10. I put it in drop list."
[1] "whichAreBijection: it took me 0.08s to identify 6 column(s) to drop."
[1]  4  5  7  8  9 11

我可以通过使用

df$col4 = NULL
df$col5 = NULL
df$col7 = NULL
df$col8 = NULL
df$col9 = NULL
df$col11 = NULL

但是，我想要算法自动完成它。

首先，我尝试生成包含whichAreBijection提议的列号的数据帧m，然后最终将其从df中删除，但结果却没有显示出任何地方：

x <- whichAreBijection(df)
y <- length(x)

m <- as.data.frame(matrix(0, ncol = y, nrow = nrow(df)))
i = 1
while (i< y+1) {
  # z <- names(df)[x[i]]
  m[,i] <- df[,x[i]]
  i<- i+1
}

以上所述生成的m具有由4、5、7、8、9、11提供的常量条目。

我看到使用一个简单的命令，如

m[,1] <- df[,4]

将m的第一列完全替换为df的第4列。

我遇到的第二个问题是在m中使用与df相同的列名。也许这听起来是完成简单任务的很长一段路。

为什么没有在m中准确地替换列? whichAreBijection?

• 如何自动让m选择要删除的df的列名作为列名？

• 是否有更好的方法来避免这种混乱，并直接删除由提出的列名？

Answer 1

我能够用以下方法处理问题1：

x <- whichAreBijection(df)
y <- length(x)
m <- as.data.frame(matrix(0, ncol = y, nrow = nrow(df)))
i = 1
while (i< y+1) {
    m[,i] <- df[,x[i], with = FALSE]
    i<- i+1
}

似乎命名的列索引值不起作用，而整数列索引则在右侧工作，我的意思是xi。这个麻烦可以通过在结尾处设置为= FALSE来避免。

问题2是下一个挑战。