R如果我有两个内容相同的独立组，我如何删除其中一个组？

Question

我的代码所处理的实际数据文件比这个要大得多，它需要能够处理不同的数据格式。下面的示例说明了具有相同内容的组的问题，以及如何只保留其中一个组。

考虑一下，我有不同内容的组。

Group   Contents
GroupA  Marble
GroupB  Marble
GroupB  Granite
GroupC  Marble
GroupD  Granite
GroupD  Glass
GroupD  Marble

在上面的例子中，GroupA和GroupC都只包含大理石，所以我想删除其中一个组。我想要的输出：

Group   Contents
GroupA  Marble
GroupB  Marble
GroupB  Granite
GroupD  Granite
GroupD  Glass
GroupD  Marble

可复制的数据：

structure(list(Group = c("GroupA", "GroupB", "GroupB", "GroupC", 
"GroupD", "GroupD", "GroupD"), Contents = c("Marble", "Marble", 
"Granite", "Marble", "Granite", "Glass", "Marble")), class = "data.frame", row.names = c(NA, 
-7L), spec = structure(list(cols = list(Group = structure(list(), class = c("collector_character", 
"collector")), Contents = structure(list(), class = c("collector_character", 
"collector"))), default = structure(list(), class = c("collector_guess", 
"collector")), skip = 1), class = "col_spec")) 

Answer 1

你可以试试：

idx <- !duplicated(with(df, cbind(Contents, ave(Contents, Group, FUN = function(x) toString(sort(x))))))
          
df[idx, ]

   Group Contents
1 GroupA   Marble
2 GroupB   Marble
3 GroupB  Granite
5 GroupD  Granite
6 GroupD    Glass
7 GroupD   Marble

Answer 2

下面是通过嵌套aggregate实现的一个选项

df[df$Group %in% aggregate(Group~.,aggregate(.~Group,df,toString),head,1)$Group,]

• Output

   Group Contents
1 GroupA   Marble
2 GroupB   Marble
3 GroupB  Granite
5 GroupD  Granite
6 GroupD    Glass
7 GroupD   Marble

Answer 3

从distinct到dplyr的一个选项

library(dplyr)
df %>% 
     arrange(across(everything())) %>%
     group_by(Group) %>%
     mutate(new = toString(Contents)) %>%
     ungroup %>%
     distinct(Contents, new, .keep_all = TRUE) %>%
     select(-new)

-output

# A tibble: 6 x 2
#  Group  Contents
#  <chr>  <chr>   
#1 GroupA Marble  
#2 GroupB Granite 
#3 GroupB Marble  
#4 GroupD Glass   
#5 GroupD Granite 
#6 GroupD Marble