r - 计算单个列中值的连续出现

Question

我希望在每次运行时都创建一个相等值的序号，例如出现次数计数器，一旦当前行中的值与上一行不同，该序号就会重新开始。

请在下面找到输入和预期输出的示例。

dataset <- data.frame(input = c("a","b","b","a","a","c","a","a","a","a","b","c"))
dataset$counter <- c(1,1,2,1,2,1,1,2,3,4,1,1)
dataset

#    input counter
# 1      a       1
# 2      b       1
# 3      b       2
# 4      a       1
# 5      a       2
# 6      c       1
# 7      a       1
# 8      a       2
# 9      a       3
# 10     a       4
# 11     b       1
# 12     c       1

我的问题与这一问题非常相似: Cumulative sequence of occurrences of values。

Answer 1

您需要使用sequence和rle:

> sequence(rle(as.character(dataset$input))$lengths)
 [1] 1 1 2 1 2 1 1 2 3 4 1 1