我試圖找到一種簡單的方法（最好是單行）將字符向量中元素的唯一組合組合并連接成一個新的字串向量。
我還希望能夠在插入的向量組合之前、中間或之后在新向量中包含任何文本行。組合不應以相反的順序重復（例如'x1_x2'但 not 'x2_x1'），也不應將元素與其自身組合（not 'x1_x1'）。
是否存在對此的快速解決方案？
期望結果的等效代碼示例：
vec <- paste0("X", 1:5)
# The underscore signifies any arbitrary line of text
c(
paste0("_", vec[1], "_", vec[2:5], "_"),
paste0("_", vec[2], "_", vec[3:5], "_"),
paste0("_", vec[3], "_", vec[4:5], "_"),
paste0("_", vec[4], "_", vec[5], "_")
)
'_X1_X2_''_X1_X3_''_X1_X4_''_X1_X5_''_X2_X3_''_X2_X4_''_X2_X5_'
'_X3_X4_''_X3_X5_''_X4_X5_'
uj5u.com熱心網友回復：
嘗試combn
> sprintf("_%s_", combn(vec, 2, paste0, collapse = "_"))
[1] "_X1_X2_" "_X1_X3_" "_X1_X4_" "_X1_X5_" "_X2_X3_" "_X2_X4_" "_X2_X5_"
[8] "_X3_X4_" "_X3_X5_" "_X4_X5_"
> paste0("_", combn(vec, 2, paste0, collapse = "_"), "_")
[1] "_X1_X2_" "_X1_X3_" "_X1_X4_" "_X1_X5_" "_X2_X3_" "_X2_X4_" "_X2_X5_"
[8] "_X3_X4_" "_X3_X5_" "_X4_X5_"
uj5u.com熱心網友回復：
你可以使用
apply(combn(vec, 2), 2, \(x) paste(x, collapse = "_"))
#> [1] "X1_X2" "X1_X3" "X1_X4" "X1_X5" "X2_X3" "X2_X4" "X2_X5" "X3_X4" "X3_X5" "X4_X5"
uj5u.com熱心網友回復：
這是tidyverse使用的版本crossing：
library(tidyverse)
crossing(x=vec, y=vec) %>%
mutate(new = paste0("_",x,"_",y,"_")) %>%
group_by(x) %>%
filter(row_number()!= 1:unique(parse_number(x))) %>%
pull(new)
[1] "_X1_X2_" "_X1_X3_" "_X1_X4_" "_X1_X5_" "_X2_X3_"
[6] "_X2_X4_" "_X2_X5_" "_X3_X4_" "_X3_X5_" "_X4_X5_"
uj5u.com熱心網友回復：
這是使用的另一個選項arrangements::combinations：
paste0("_",
apply(arrangements::combinations(x = vec, k = 2), 1, paste, collapse = "_"),
"_")
#[1] "_X1_X2_" "_X1_X3_" "_X1_X4_" "_X1_X5_" "_X2_X3_" "_X2_X4_" "_X2_X5_" "_X3_X4_" "_X3_X5_" "_X4_X5_"
轉載請註明出處，本文鏈接：https://www.uj5u.com/gongcheng/468109.html
下一篇：創建具有多個資料序列的字符向量