將一個矢量分成塊，直到發生事件

Question

我有一個矢量x <- c("H","H","T","H","T","T","H","H","H","H","T")從硬幣翻轉。我想從上面的向量中構造一個帶有兩個變量（模式，長度）的數據幀。

模式字段會像{HHT，HT，T，HHHHT}和相應的長度將是{2,1,0,4}

我的內涵是獲得連續頭的計數，直到尾部出現在硬幣翻轉。

Answer 1

鑑於矢量

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 

---

說明

關閉載體引入串

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

查找所有的T小號

位置

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

的T S之間H數將每個值之間的差，減去1

附加一個領先0和找到每個值之間的差。

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計算T的所有H，則添加零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