r - 基于重复逻辑向量元素粘贴字符串

Question

我有一个字符串向量

vec <- c("apple", "banana", "plum", "cherry", "cake", "ginger")

我有一个相应的逻辑向量

lvec <- c(TRUE, FALSE, TRUE, FALSE, FALSE, TRUE)

我想粘贴 (paste0) 具有 FALSE(或 TRUE)序列的元素。

期望的输出:

c("apple", "banana", "plum", "cherrycake", "ginger")

Answer 1

我首先使用rle，然后修改“值”以便能够轻松地将数据拆分为所需的组。然后使用 *apply 我们可以使用带有所需参数的粘贴。

x <- c("apple", "banana", "plum", "cherry", "cake", "ginger")
y <- c(TRUE, FALSE, TRUE, FALSE, FALSE, TRUE)
r <- rle(y)
r$values <- seq_along(r$values)
sapply(split(x, inverse.rle(r)), paste, collapse = "")
# alternatively but I didn't initially think of tapply
tapply(x, inverse.rle(r), paste, collapse = "")

这给出了

> sapply(split(x, inverse.rle(r)), paste, collapse = "")
           1            2            3            4            5 
     "apple"     "banana"       "plum" "cherrycake"     "ginger"