为数据添加一列。将行均匀分配给列表中的值的框架答案

【问题标题】：Add a column to a data. frame which evenly assign rows to values in a list为数据添加一列。将行均匀分配给列表中的值的框架
【发布时间】：2020-12-06 01:50:04
【问题描述】：

我有一个数据框，其中每一行都是一个家庭，我有一个采访者列表。目的是将访问员分配到住户，每个访问员应该在每个城市获得相同数量的住户。例如，

example <- data.frame(city = c("Los Angeles", "Los Angeles", "Los Angeles", 
                               "San Diego", "San Diego", "San Diego", "San Diego", "San Diego",
                               "Santa Barbara", "Santa Barbara", "Santa Barbara", "Santa Barbara", "Santa Barbara"), 
                      household_id = seq(1, 13))
interviewer <- c("A", "B", "C")

3位访谈员会去所有城市，每个城市大约会采访1/3的住户，所以预期产出是

output <- data.frame(city = c("Los Angeles", "Los Angeles", "Los Angeles", 
                               "San Diego", "San Diego", "San Diego", "San Diego", "San Diego",
                               "Santa Barbara", "Santa Barbara", "Santa Barbara", "Santa Barbara", "Santa Barbara"), 
                      household_id = seq(1, 13),
                     interviewer = c("A", "B", "C",
                                     "A", "A", "B", "B", "C",
                                     "A", "A", "B", "B", "C"))

【问题讨论】：

标签： r dataframe tidyverse

【解决方案1】：

您可以尝试使用rep 为每个city 重复interviewer。

library(dplyr)

example %>%
  group_by(city) %>%
  mutate(interviewer = rep(interviewer, length.out = n()))

#   city          household_id interviewer
#   <chr>                <int> <chr>      
# 1 Los Angeles              1 A          
# 2 Los Angeles              2 B          
# 3 Los Angeles              3 C          
# 4 San Diego                4 A          
# 5 San Diego                5 B          
# 6 San Diego                6 C          
# 7 San Diego                7 A          
# 8 San Diego                8 B          
# 9 Santa Barbara            9 A          
#10 Santa Barbara           10 B          
#11 Santa Barbara           11 C          
#12 Santa Barbara           12 A          
#13 Santa Barbara           13 B

【讨论】：

谢谢！这太优雅了！ I. 不知道有一个 length.out 参数。