r - 查找向量中最长的重复元素

Question

我想在以下向量中找到等于“1”的连续重复元素的开始和结束索引。向量的值可以等于“1”或 NA。

例如:

out2
 [1] "1" "1" "1" "1" "1" "1" "1" "1" "1" "1" "1" "1" "1" "1" "1" "1" "1" "1" "1" "1"
[21] "1" NA  NA  NA  NA  NA  "1" "1" "1" "1" "1" "1" NA  NA  NA  NA  NA  NA  NA  NA

输出应该如下所示

    [,1] [,2]
[1,]  1   21
[2,]  27  32

Answer 1

尝试rle:

x <- c(1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 
1, NA, NA, NA, NA, NA, 1, 1, 1, 1, 1, 1, NA, NA, NA, NA, NA, 
NA, NA, NA)

with(rle(x), {
  ok <- !is.na(values)
  ends <- cumsum(lengths)[ok]
  starts <- ends - lengths[ok] + 1
  cbind(starts, ends)
})

给予:

     starts ends
[1,]      1   21
[2,]     27   32