R dplyr：创建面板数据的计数答案

【问题标题】：R dplyr: tally to create Panel DataR dplyr：创建面板数据的计数
【发布时间】：2020-03-18 09:58:24
【问题描述】：

我有以下数据框：

D <- data.frame("Id" = c("a","b","c","d","e","f","g"), "Group" = c("1","1","1","2","2","2","2"),"Time" = c("1","1","2","1","2","3","3"))

  Id Group Time
1  a     1    1
2  b     1    1
3  c     1    2
4  d     2    1
5  e     2    2
6  f     2    3
7  g     2    3

我想按周期和时间计算保持圆柱结构的个人数量。经典的方法是使用 dplyr

D %>% group_by(Group,Time) %>% tally()
  Group Time      n
  <fct> <fct> <int>
1 1     1         2
2 1     2         1
3 2     1         1
4 2     2         1
5 2     3         2

但结构不平衡：此处第 1 组未显示时间 3，但我希望看到它与 0 相关联，如下所示：

  Group Time      n
  <fct> <fct> <int>
1 1     1         2
2 1     2         1
3 1     3         0
4 2     1         1
5 2     2         1
6 2     3         2

有没有办法在 group_by 之后平衡结果？有人遇到过类似的事情吗？在此先感谢

【问题讨论】：

标签： r dplyr panel

【解决方案1】：

由于Time 是因子变量，我们可以将count 与.drop = FALSE 一起使用，因为默认情况下count 会以0 计数放弃观察。

library(dplyr)
D %>% count(Group, Time, .drop = FALSE)

#  Group Time      n
#  <fct> <fct> <int>
#1 1     1         2
#2 1     2         1
#3 1     3         0
#4 2     1         1
#5 2     2         1
#6 2     3         2

我们也可以使用 tally 的相同方法。

D %>% group_by(Group,Time, .drop = FALSE) %>% tally()

或complete

D %>%  count(Group, Time) %>% tidyr::complete(Group, Time, fill = list(n = 0))

【讨论】：

【解决方案2】：

Ronak Shah 答案的小替代方案：

library(tidyr)
library(dplyr)

D <- data.frame("Id" = c("a","b","c","d","e","f","g"), "Group" = c("1","1","1","2","2","2","2"),"Time" = c("1","1","2","1","2","3","3"))

D %>% 
  group_by(Group,Time) %>% 
  tally() %>% 
  ungroup() %>%
  complete(Group, Time)

【讨论】：

【解决方案3】：

在base R中，我们可以使用table

as.data.frame(table(D[-1]))

【讨论】：