如何在 R 中的每个位置使用给定的字母集生成所有字符串排列

Question

我确信这之前已经问过并解决了，但可能我正在寻找错误的术语。我找不到相关线程。

在R中，我想生成所有可能的单词/字符串，其中每个位置只能采用一组值，例如

• pos1 可以是 ABC
• POS2 可以是 ABCD
• pos3 可以是 ABC
• POS4 可以是 BCD

等。 例如：BABC 是一个解决方案，但DABC不是。

如果您能指出我的解决方案，我将不胜感激！

谢谢你的时间！

。咚！，咚咚咚咚...

感谢 芽

Answer 1

在 Base R 中，我们可以执行以下操作

pos1 <- c('A','B','C')
pos2 <- c('A','B','C','D')
pos4 <- c('B','C','D')
AllPos <- list(pos1,pos2,pos3,pos4)
result <- AllPos[1]
for(i in AllPos[-1] ){
result <-  apply(merge(result ,i),1,paste0,collapse="")
}
> result 
[1] "AAAB" "BAAB" "CAAB" "ABAB" "BBAB" "CBAB" "ACAB" "BCAB" "CCAB" "ADAB"
[11] "BDAB" "CDAB" "AABB" "BABB" "CABB" "ABBB" "BBBB" "CBBB" "ACBB" "BCBB"
[21] "CCBB" "ADBB" "BDBB" "CDBB" "AACB" "BACB" "CACB" "ABCB" "BBCB" "CBCB"
[31] "ACCB" "BCCB" "CCCB" "ADCB" "BDCB" "CDCB" "AAAC" "BAAC" "CAAC" "ABAC"
[41] "BBAC" "CBAC" "ACAC" "BCAC" "CCAC" "ADAC" "BDAC" "CDAC" "AABC" "BABC"
[51] "CABC" "ABBC" "BBBC" "CBBC" "ACBC" "BCBC" "CCBC" "ADBC" "BDBC" "CDBC"
[61] "AACC" "BACC" "CACC" "ABCC" "BBCC" "CBCC" "ACCC" "BCCC" "CCCC" "ADCC"
[71] "BDCC" "CDCC" "AAAD" "BAAD" "CAAD" "ABAD" "BBAD" "CBAD" "ACAD" "BCAD"
[81] "CCAD" "ADAD" "BDAD" "CDAD" "AABD" "BABD" "CABD" "ABBD" "BBBD" "CBBD"
[91] "ACBD" "BCBD" "CCBD" "ADBD" "BDBD" "CDBD" "AACD" "BACD" "CACD" "ABCD"
[101] "BBCD" "CBCD" "ACCD" "BCCD" "CCCD" "ADCD" "BDCD" "CDCD"

Answer 2

一个快速而肮脏的基本 R 解决方案...

p1 <- "ABC"
p2 <- "ABCD"
p3 <- "ABC"
p4 <- "BCD"
apply(expand.grid(strsplit(p1, "")[[1]], strsplit(p2, "")[[1]],
strsplit(p3, "")[[1]], strsplit(p4, "")[[1]]), 1, paste0, 
collapse = "")
#>   [1] "AAAB" "BAAB" "CAAB" "ABAB" "BBAB" "CBAB" "ACAB" "BCAB" "CCAB" "ADAB"
#>  [11] "BDAB" "CDAB" "AABB" "BABB" "CABB" "ABBB" "BBBB" "CBBB" "ACBB" "BCBB"
#>  [21] "CCBB" "ADBB" "BDBB" "CDBB" "AACB" "BACB" "CACB" "ABCB" "BBCB" "CBCB"
#>  [31] "ACCB" "BCCB" "CCCB" "ADCB" "BDCB" "CDCB" "AAAC" "BAAC" "CAAC" "ABAC"
#>  [41] "BBAC" "CBAC" "ACAC" "BCAC" "CCAC" "ADAC" "BDAC" "CDAC" "AABC" "BABC"
#>  [51] "CABC" "ABBC" "BBBC" "CBBC" "ACBC" "BCBC" "CCBC" "ADBC" "BDBC" "CDBC"
#>  [61] "AACC" "BACC" "CACC" "ABCC" "BBCC" "CBCC" "ACCC" "BCCC" "CCCC" "ADCC"
#>  [71] "BDCC" "CDCC" "AAAD" "BAAD" "CAAD" "ABAD" "BBAD" "CBAD" "ACAD" "BCAD"
#>  [81] "CCAD" "ADAD" "BDAD" "CDAD" "AABD" "BABD" "CABD" "ABBD" "BBBD" "CBBD"
#>  [91] "ACBD" "BCBD" "CCBD" "ADBD" "BDBD" "CDBD" "AACD" "BACD" "CACD" "ABCD"
#> [101] "BBCD" "CBCD" "ACCD" "BCCD" "CCCD" "ADCD" "BDCD" "CDCD"

^{创建于 2020-06-18 由 reprex 软件包 (v0.3.0(}

Answer 3

expand.grid是你的朋友。

一个简单的解决方案：

apply(expand.grid(list(
LETTERS[1:3],
LETTERS[1:4],
LETTERS[1:3],
LETTERS[2:4])), 1, paste, collapse = "")
#>   [1] "AAAB" "BAAB" "CAAB" "ABAB" "BBAB" "CBAB" "ACAB" "BCAB" "CCAB" "ADAB"
#>  [11] "BDAB" "CDAB" "AABB" "BABB" "CABB" "ABBB" "BBBB" "CBBB" "ACBB" "BCBB"
#>  [21] "CCBB" "ADBB" "BDBB" "CDBB" "AACB" "BACB" "CACB" "ABCB" "BBCB" "CBCB"
#>  [31] "ACCB" "BCCB" "CCCB" "ADCB" "BDCB" "CDCB" "AAAC" "BAAC" "CAAC" "ABAC"
#>  [41] "BBAC" "CBAC" "ACAC" "BCAC" "CCAC" "ADAC" "BDAC" "CDAC" "AABC" "BABC"
#>  [51] "CABC" "ABBC" "BBBC" "CBBC" "ACBC" "BCBC" "CCBC" "ADBC" "BDBC" "CDBC"
#>  [61] "AACC" "BACC" "CACC" "ABCC" "BBCC" "CBCC" "ACCC" "BCCC" "CCCC" "ADCC"
#>  [71] "BDCC" "CDCC" "AAAD" "BAAD" "CAAD" "ABAD" "BBAD" "CBAD" "ACAD" "BCAD"
#>  [81] "CCAD" "ADAD" "BDAD" "CDAD" "AABD" "BABD" "CABD" "ABBD" "BBBD" "CBBD"
#>  [91] "ACBD" "BCBD" "CCBD" "ADBD" "BDBD" "CDBD" "AACD" "BACD" "CACD" "ABCD"
#> [101] "BBCD" "CBCD" "ACCD" "BCCD" "CCCD" "ADCD" "BDCD" "CDCD"

^{创建于 2020-06-18 由 reprex 软件包 (v0.3.0(}