将一个矢量分成块，直到发生事件

Question

我有一个矢量x <- c("H","H","T","H","T","T","H","H","H","H","T")从硬币翻转。我想从上面的向量中构造一个带有两个变量（模式，长度）的数据帧。

模式字段会像{HHT，HT，T，HHHHT}和相应的长度将是{2,1,0,4}

我的内涵是获得连续头的计数，直到尾部出现在硬币翻转。

Answer 1

鉴于矢量

x <- c("H","H","T","H","T","T","H","H","H","H","T") 

diff(c(0, as.integer(gregexpr("T", paste0(x, collapse = ""))[[1]]))) - 1 
# [1] 2 1 0 4 

---

说明

关闭载体引入串

paste0(x, collapse = "") 
## "HHTHTTHHHHT" 

查找所有的T小号

位置

as.integer(gregexpr("T", paste0(x, collapse = ""))[[1]]) 
## [1] 3 5 6 11 

的T S之间H数将每个值之间的差，减去1

附加一个领先0和找到每个值之间的差。

diff(c(0, as.integer(gregexpr("T", paste0(x, collapse = ""))[[1]]))) - 1 
[1] 2 1 0 4 

Answer 2

您可以使用rle计算T的所有H，则添加零H系列：

x <- c("H","H","T","H","T","T","H","H","H","H","T") 
y <- rle(x=='T') 
table(c(rep(0,sum(y$lengths[y$values & y$lengths>1]-1)),y$lengths[!y$values])) 


0 1 2 4 
1 1 1 1