r - 不断收到错误: Expecting a single value: [extent=2] in summarise

Question

运行以下脚本时始终出现此错误-使用dplyr包中的summary

analysis <- df %>% group_by(Year, Week, YearWeek, Cad.Name, CamName, Abs.ID, Place.Name, Pull.Name) %>% 
  summarise(visits=sum(Visits)) %>%
  group_by(Year, Week, YearWeek, Cad.Name, CamName, Abs.ID, Place.Name) %>% 
  summarise(video=unique(Video.Name),visits=sum(Visits)) %>%
  arrange(Year,Week)

Video.Name是一个问题，需要在汇总之前将其添加到groupby才能执行。在访问过程中，我需要按视频的唯一计数来总结-有什么想法吗？我不断收到这些错误:

Error: Expecting a single value: [extent=2].
In addition: Warning messages:
1: Factor `YearWeek` contains implicit NA, consider using `forcats::fct_explicit_na` 
2: Factor `YearWeek` contains implicit NA, consider using `forcats::fct_explicit_na`

Answer 1

错误应该来自unique(Video.Name)，它的length可以大于1，但是summarise每个组仅返回一行。我们可以将其包装在list中。

library(dplyr)
df %>%
   group_by(Year, Week, YearWeek, Cad.Name, CamName, 
        Abs.ID, Place.Name, Pull.Name) %>% 
   summarise(visits=sum(Visits)) %>%
   group_by(Year, Week, YearWeek, Cad.Name, CamName, Abs.ID, Place.Name) %>% 
   summarise(video=list(unique(Video.Name)),visits=sum(Visits)) %>%
   arrange(Year, Week)