1

I have character data like this

[[1]]
[1] "F" "S"

[[2]]
[1] "Y" "Q" "Q"

[[3]]
[1] "C" "T"

[[4]]
[1] "G" "M"

[[5]]
[1] "A" "M"

And I want to generate all permutations for each individual list (not mixed between lists) and combine them together into one big list.

For example, for the first and second lists, which are "F" "S" and "Y" "Q" "Q", I want to get the permutation lists as c("FS", "SF"), and c("YQQ", "QYQ", "QQY"), and then combine them into one.

Ian Campbell
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RainieJin
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  • Is the data a list of lists, or a list of vectors? It would help us understand better if you include some code to generate example data. eg: `X <- list(c("F","S"), c("Y", "Q", "Q"))` – Damian Apr 08 '21 at 22:32
  • This may be a duplicate of https://stackoverflow.com/questions/11095992/generating-all-distinct-permutations-of-a-list-in-r – Damian Apr 08 '21 at 22:34

3 Answers3

1

It looks like your desired output is not exactly the same as this related post (Generating all distinct permutations of a list in R). But we can build on the answer there.

library(combinat)

# example data, based on your description
X <- list(c("F","S"), c("Y", "Q", "Q"))

result <- lapply(X, function(x1) {
    unique(sapply(permn(x1), function(x2) paste(x2, collapse = "")))
})

print(result)

Output

 [[1]]
 [1] "FS" "SF"

 [[2]]
 [1] "YQQ" "QYQ" "QQY"

The first (outer) lapply iterates over each element of the list, which contains the individual letters (in a vector). With each iteration the permn takes the individual letters (eg "F" and "S"), and returns a list object with all possible permutations (e.g "F" "S" and "S" F"). To format the output as you described, the inner sapply takes each those permutations and collapses them into a single character value, filtered for unique values.

Damian
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1

Here's an approach with combinat::permn:

library(combinat)
lapply(data,function(x)unique(sapply(combinat::permn(x),paste,collapse = "")))
#[[1]]
#[1] "FS" "SF"
#
#[[2]]
#[1] "YQQ" "QYQ" "QQY"
#
#[[3]]
#[1] "CT" "TC"
#
#[[4]]
#[1] "GM" "MG"
#
#[[5]]
#[1] "AM" "MA"

Or together with unlist:

unlist(lapply(data,function(x)unique(sapply(combinat::permn(x),paste,collapse = ""))))
# [1] "FS"  "SF"  "YQQ" "QYQ" "QQY" "CT"  "TC"  "GM"  "MG"  "AM"  "MA"

Data:

data <- list(c("F", "S"), c("Y", "Q", "Q"), c("C", "T"), c("G", "M"), 
    c("A", "M"))
Ian Campbell
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1
library(combinat)

final <- unlist(lapply(X , function(test_X) lapply(permn(test_X), function(x) paste(x,collapse='')) ))
Ashish Baid
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