通过 R 计算数字组合答案

【问题标题】：Calculating number combinations through R通过 R 计算数字组合
【发布时间】：2020-12-02 09:16:12
【问题描述】：

我有以下数据。我想首先找出每个位置值上出现次数最多的数字。显然，一个地方可以有 0 到 9 的 10 种可能性。比我想要一个选项，我可以选择 5 个最高出现次数或 6 个或 7 或 8 个最高出现次数，例如如果我选择 5，那么程序应该取前 5 次出现，或者如果我选择 8，那么程序应该去掉最少出现的 2 个数字并取所有其他数字。

数据示例：

我想要选择 5、6、7 或 8 个最高出现次数和 2 或 3 或 4 个数字组合的选项

预期结果，2个数字组合根据前8个出现等等。

预期结果，3个数字组合基于前8个出现等等。

我尝试过的代码

getwd()
setwd("C:/Users/aziq/Desktop")
library(xlsx)
x <- read.xlsx("numbers.xlsx","Sheet1")

    generate_combinations <- function(x, pos, n) {
      #select first pos characters from each string
      #split each character and create a matrix
      mat <- do.call(rbind, strsplit(substr(x, 1, pos), ''))
      #Find top n occurrence in each column of matrix
      tmp <- apply(mat, 2, function(x) tail(names(sort(table(x))), n))
      #Create all combinations of top occurrences.
      do.call(expand.grid, asplit(tmp, 2))
    }
    
    generate_combinations(x, 2, 8)
    nrow(generate_combinations(x, 2, 8))

显示错误

Error in asplit(tmp, 2) : dim(x) must have a positive length

输出结果：

> dput(x)
structure(list(X076060 = c("693022", "585821", "980575", "438068", 
"766214", "051726", "060417", "822591", "015507", "635576", "180231", 
"212238", "417651", "631269", "720767", "348344", "532148", "748085", 
"474026", "380897", "512421", "749492", "423616", "950330", "930079", 
"097759", "638901", "319356", "683308", "818127", "880675", "256095", 
"639187", "339904", "945437", "799571", "466063", "428853", "397799", 
"782034", "462486", "739342", "879023", "419264", "793319", "603131", 
"315791", "351701", "151747", "365656", "982700", "348093", "793392", 
"946875", "912108", "070001", "780515", "222468", "345439", "234846", 
"227112", "757243", "341747", "480781", "906624", "868265", "388572", 
"947873", "898895", "452518", "738580", "217342", "849951", "437382", 
"247068", "743776", "562584", "636948", "049434", "139296", "688436", 
"443629")), class = "data.frame", row.names = c(NA, -82L))

【问题讨论】：

您想在每个位置都获得前 8 次出现？您能否以我们可以复制的可复制格式提供您的数据示例？
@RonakShah - 嗨，我已经编辑了数据格式，你可以复制。如果我想选择前 5、6、7 或 8 次出现，我想要一个选项，并且基于选择代码应该产生 2 位、3 位、4 位的组合结果。所以对于 8 次出现的选择，2 位组合将是 64 (8*8)，3 位组合将是 512 (8*8*8)，4 位组合将是 4096 个数字 (8*8*8*8)。跨度>
对于 2 位组合，我们只考虑数据的前 2 位？对于 3 位数字，只考虑前 3 位数字等等？最高出现次数是基于每个单独的位置？
是的，这是正确的，数据会告诉我们每个位置值的最高出现次数。

标签： r combinations

【解决方案1】：

我们可以写一个函数：

generate_combinations <- function(x, pos, n) {
  if(pos == 1) {
    return(data.frame(Var1 = names(sort(table(substr(x, 1, pos)),
                      = decreasing = TRUE)[1:n])))
  }
  #select first pos characters from each string
  #split each character and create a matrix
  mat <- do.call(rbind, strsplit(substr(x, 1, pos), ''))
  #Find top n occurrence in each column of matrix
  tmp <- apply(mat, 2, function(x) tail(names(sort(table(x))), n))
  #Create all combinations of top occurrences.
  do.call(expand.grid, asplit(tmp, 2))
}

generate_combinations(x, 2, 8)
#   Var1 Var2
#1     0    2
#2     2    2
#3     8    2
#4     6    2
#5     9    2
#6     3    2
#7     4    2
#8     7    2
#9     0    5
#10    2    5
#...
#...

nrow(generate_combinations(x, 2, 8))
#[1] 64
nrow(generate_combinations(x, 3, 8))
#[1] 512

数据

x <- c("076060", "693022", "585821", "980575", "438068", "766214", 
"051726", "060417", "822591", "015507", "635576", "180231", "212238", 
"417651", "631269", "720767", "348344", "532148", "748085", "474026", 
"380897", "512421", "749492", "423616", "950330", "930079", "097759", 
"638901", "319356", "683308", "818127", "880675", "256095", "639187", 
"339904", "945437", "799571", "466063", "428853", "397799", "782034", 
"462486", "739342", "879023", "419264", "793319", "603131", "315791", 
"351701", "151747", "365656", "982700", "348093", "793392", "946875", 
"912108", "070001", "780515", "222468", "345439", "234846", "227112", 
"757243", "341747", "480781", "906624", "868265", "388572", "947873", 
"898895", "452518", "738580", "217342", "849951", "437382", "247068", 
"743776", "562584", "636948", "049434", "139296", "688436", "443629")

【讨论】：

那是x 一个向量。如果您有数据作为名为 df 的数据框，请使用 df$column_name 而不是 x。类似generate_combinations(df$column_name, 2, 8)
我在 excel 文件中只有这些数字的列表。
您想在 excel 或 R 中执行此操作吗？如果您想在 R 中执行此操作，请将数据读入 R 并参考我上面的评论。
是的 R 绝对是，所以我会读取 excel 文件并将其列分配给 x？你能提供这样做的代码吗？假设我的文件名是 numbers.xlsx
stackoverflow.com/questions/7049272/…