如何随机化列顺序的子集

Question

我有一个数据框，我想随机打乱某些列的顺序。例如，这里有一个例子来表示我所拥有的：

V1  V2  V3  V4  V5  V6  V7  V8  V9  V10 V11 V12 V13 V14
ch1 12  A   9   10  6   5   6   3   4   6   5   7   5
ch2 13  T   7   10  1   7   3   3   3   1   7   8   6
ch3 14  T   5   7   7   2   6   8   1   1   8   1   5
ch4 15  G   8   9   2   7   9   7   7   3   10  10  4
ch5 16  T   8   2   8   2   4   7   1   8   10  3   2

我想保持前三列相同（V1-V3），然后随机打乱其余列的顺序（V4-V14）。例如，

V1  V2  V3  V6  V5  V11 V4  V14 V10 V8  V7  V13 V12 V9
ch1 12  A   6   10  6   9   5   4   6   5   7   5   3
ch2 13  T   1   10  1   7   6   3   3   7   8   7   3
ch3 14  T   7   7   1   5   5   1   6   2   1   8   8
ch4 15  G   2   9   3   8   4   7   9   7   10  10  7
ch5 16  T   8   2   8   8   2   1   4   2   3   10  7

我发现了很多在列中排列行的方法，但还没有遇到任何打乱列顺序的方法。任何帮助，将不胜感激。

Answer 1

您可以单独保留前三列，而将所有其他列打乱

df[c(1:3, sample(4:ncol(df)))]

让我们通过仅返回列名称来了解它如何与 mtcars 一起工作。

replicate(7, names(mtcars[c(1:3, sample(4:ncol(mtcars)))]))
#       [,1]   [,2]   [,3]   [,4]   [,5]   [,6]   [,7]  
#  [1,] "mpg"  "mpg"  "mpg"  "mpg"  "mpg"  "mpg"  "mpg" 
#  [2,] "cyl"  "cyl"  "cyl"  "cyl"  "cyl"  "cyl"  "cyl" 
#  [3,] "disp" "disp" "disp" "disp" "disp" "disp" "disp"
#  [4,] "carb" "am"   "hp"   "qsec" "am"   "am"   "am"  
#  [5,] "wt"   "hp"   "drat" "carb" "carb" "wt"   "carb"
#  [6,] "hp"   "gear" "vs"   "drat" "qsec" "gear" "qsec"
#  [7,] "drat" "carb" "am"   "vs"   "wt"   "vs"   "hp"  
#  [8,] "qsec" "vs"   "carb" "wt"   "gear" "hp"   "gear"
#  [9,] "vs"   "drat" "gear" "am"   "drat" "drat" "drat"
# [10,] "am"   "wt"   "qsec" "gear" "vs"   "qsec" "wt"  
# [11,] "gear" "qsec" "wt"   "hp"   "hp"   "carb" "vs"

我们可以看到每个运行的前三个列名称（此处显示为行）保持不变，而其他的则不同。

如何随机化列顺序的子集

How to randomize a subset of the column order

r

shuffle

permutation