如何对 R 中的列表进行条件合并？

Question

我有一个清单。
我想成对比较元素，然后在满足条件时合并元素
示例列表：

[[1]]
[1] "466" "1758" "975"

[[2]]
[1] "1528" "185"  "975" 

[[3]]
[1] "1528" "185"  "975" 

[[4]]
[1] "2892" "758"  "971" 

[[5]]
[1] "1321" "274"  "969" 

[[6]]
[1] "1321"  "274" "969" 

[[7]]
[1] "115"  "1321" "969" 

[[8]]
[1] "1321" "441"  "969" 

[[9]]
[1] "504" "61"  "948"

[[10]]
[1] "504"  "61" "948" 

假设条件很简单：如果元素 1 等于元素 2，则合并它们并从列表中删除第二个元素。

预期输出：

[[1]]
[1] "466" "1758" "975"

[[2]]
[1] "1528" "185"  "975" "1528" "185"  "975" 

[[3]]
[1] "2892" "758"  "971" 

[[4]]
[1] "1321" "274"  "969" "1321"  "274" "969" 

[[5]]
[1] "115"  "1321" "969" 

[[6]]
[1] "1321" "441"  "969" 

[[7]]
[1] "504" "61"  "948" "504"  "61" "948" 

谢谢

Answer 1

我们可以使用duplicated 创建一个逻辑索引，从list 中提取元素并与Map 连接，更新list 并根据索引仅提取那些元素

i1 <- duplicated(lst1)
i2 <- duplicated(lst1, fromLast = TRUE)
lst2 <- lst1
lst2[i1] <- Map(c, lst1[i1], lst1[i2])
lst2[!i2]
#[[1]]
#[1] "466"  "1758" "975" 

#[[2]]
#[1] "1528" "185"  "975"  "1528" "185"  "975" 

#[[3]]
[#1] "2892" "758"  "971" 

#[[4]]
#[1] "1321" "274"  "969"  "1321" "274"  "969" 

#[[5]]
#[1] "115"  "1321" "969" 

#[[6]]
#[1] "1321" "441"  "969" 

#[[7]]
#[1] "504" "61"  "948" "504" "61"  "948"

---

或使用split

lst2[i1] <- lapply(split(lst1[i1|i2], lst1[i1|i2], drop = TRUE), unlist)

数据

lst1 <- list(c("466", "1758", "975"), c("1528", "185", "975"), c("1528", 
"185", "975"), c("2892", "758", "971"), c("1321", "274", "969"
), c("1321", "274", "969"), c("115", "1321", "969"), c("1321", 
"441", "969"), c("504", "61", "948"), c("504", "61", "948"))