dplyr:使用数据帧中n次连续重复的整数来突变新列 [英] dplyr: Mutate a new column with sequential repeated integers of n time in a dataframe

问题描述

我正在努力解决一个可能很简单的问题.我有1列n列的数据框(n是3的倍数).我想给第二列添加整数，例如:1,1,1,2,2,2,3,3,3,4,4,4,5,5,5，..如何使用dplyr作为不同长度的行(3的倍数)的通用解决方案.

I am struggling with one maybe easy question. I have a dataframe of 1 column with n rows (n is a multiple of 3). I would like to ad a second column with integers like: 1,1,1,2,2,2,3,3,3,4,4,4,5,5,5,.. How can I achieve this with dplyr as a general solution for different length of rows (all multiple of 3).

我尝试过:

df <- tibble(Col1 = c(1:12)) %>% 
  mutate(Col2 = rep(1:4, each=3))

这有效.但是我想为n行提供解决方案，每行= 3​​.非常感谢！

This works. But I would like to have a solution for n rows, each = 3 . Many thanks!

推荐答案

您可以在 rep 中指定每个和 length.out 参数.

You can specify each and length.out parameter in rep.

library(dplyr)

tibble(Col1 = c(1:12)) %>% 
  mutate(Col2 = rep(row_number(), each=3, length.out = n()))

#    Col1  Col2
#   <int> <int>
# 1     1     1
# 2     2     1
# 3     3     1
# 4     4     2
# 5     5     2
# 6     6     2
# 7     7     3
# 8     8     3
# 9     9     3
#10    10     4
#11    11     4
#12    12     4

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