[英]R: Find unique vectors in list of vectors
我有一個向量列表
list_of_vectors <- list(c("a", "b", "c"), c("a", "c", "b"), c("b", "c", "a"), c("b", "b", "c"), c("c", "c", "b"), c("b", "c", "b"), c("b", "b", "c", "d"), NULL)
對於此列表,我想知道哪些向量在元素方面是唯一的。 也就是說,我想要以下輸出
[[1]]
[1] "a" "b" "c"
[[2]]
[1] "b" "b" "c"
[[3]]
[1] "c" "c" "b"
[[4]]
[1] "b" "b" "c" "d"
[[5]]
[1] NULL
R中是否有執行此檢查的功能? 還是我需要通過編寫函數來做很多變通辦法?
我目前沒有那么優雅的解決方案:
# Function for turning vectors into strings ordered by alphabet
stringer <- function(vector) {
if(is.null(vector)) {
return(NULL)
} else {
vector_ordered <- vector[order(vector)]
vector_string <- paste(vector_ordered, collapse = "")
return(vector_string)
}
}
# Identifying unique strings
vector_strings_unique <- unique(lapply(list_of_vectors, function(vector)
stringer(vector)))
vector_strings_unique
[[1]]
[1] "abc"
[[2]]
[1] "bbc"
[[3]]
[1] "bcc"
[[4]]
[1] "bbcd"
[[5]]
NULL
# Function for splitting the strings back into vectors
splitter <- function(string) {
if(is.null(string)) {
return(NULL)
} else {
vector <- unlist(strsplit(string, split = ""))
return(vector)
}
}
# Applying function
lapply(vector_strings_unique, function(string) splitter(string))
[[1]]
[1] "a" "b" "c"
[[2]]
[1] "b" "b" "c"
[[3]]
[1] "c" "c" "b"
[[4]]
[1] "b" "b" "c" "d"
[[5]]
[1] NULL
它可以解決問題,可以將其重寫為單個函數,但是必須有一個更優雅的解決方案。
我們可以sort
list
元素進行sort
,應用duplicated
元素以獲得唯一元素的邏輯索引,並基於該元素對list
子集化
list_of_vectors[!duplicated(lapply(list_of_vectors, sort))]
#[[1]]
#[1] "a" "b" "c"
#[[2]]
#[1] "b" "b" "c"
#[[3]]
#[1] "c" "c" "b"
#[[4]]
#[1] "b" "b" "c" "d"
#[[5]]
#NULL
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