汇总多个必须分组的列 tidyverse答案

【问题标题】：Summarise multiple columns that have to be grouped tidyverse汇总多个必须分组的列 tidyverse
【发布时间】：2021-08-02 11:52:06
【问题描述】：

我有一个包含如下数据的数据框：

df <- data.frame(
    group1 = c("High","High","High","Low","Low","Low"),
    group2 = c("male","female","male","female","male","female"),
    one = c("yes","yes","yes","yes","no","no"), 
    two = c("no","yes","no","yes","yes","yes"), 
    three = c("yes","no","no","no","yes","yes")
)

我想总结变量one、two 和three 中是/否的计数，通常我会通过df %>% group_by(group1,group2,one) %>% summarise(n()) 来完成。有什么方法可以汇总所有三列，然后将它们全部绑定到一个输出 df 中，而无需在每一列上手动执行代码？我尝试使用 for 循环，但我无法让 group_by() 识别我作为输入提供的列名

【问题讨论】：

接受答案

标签： r tidyverse summarize

【解决方案1】：

获取长格式数据和count：

library(dplyr)
library(tidyr)

df %>% pivot_longer(cols = one:three) %>% count(group1, group2, value)

#  group1 group2 value     n
#  <chr>  <chr>  <chr> <int>
#1 High   female no        1
#2 High   female yes       2
#3 High   male   no        3
#4 High   male   yes       3
#5 Low    female no        2
#6 Low    female yes       4
#7 Low    male   no        1
#8 Low    male   yes       2

【讨论】：

【解决方案2】：

这可以仅在dplyr 中完成（无需使用tidyr::pivot_*），但输出格式略有不同。（即使没有rowwise，这个也可以工作，尽管我不知道它的确切原因）

df <- data.frame(
  group1 = c("High","High","High","Low","Low","Low"),
  group2 = c("male","female","male","female","male","female"),
  one = c("yes","yes","yes","yes","no","no"), 
  two = c("no","yes","no","yes","yes","yes"), 
  three = c("yes","no","no","no","yes","yes")
)
library(dplyr)

df %>%
  group_by(group1, group2) %>%
  summarise(yes_count = sum(c_across(everything()) == 'yes'),
            no_count = sum(c_across(one:three) == 'no'), .groups = 'drop')
#> # A tibble: 4 x 4
#>   group1 group2 yes_count no_count
#>   <chr>  <chr>      <int>    <int>
#> 1 High   female         2        1
#> 2 High   male           3        3
#> 3 Low    female         4        2
#> 4 Low    male           2        1

^{由reprex package (v2.0.0) 于 2021-05-12 创建}

【讨论】：

原因是== 正在将其转换为逻辑向量。检查df %>% group_by(group1, group2) %>% summarise(new = list(c_across(everything()) == "yes")) %>% pull(new)
即当您执行c_across 时，它返回vector df %>% group_by(group1, group2) %>% summarise(new = list(c_across(everything()))) -> out 现在检查out 和df 和out$new。对于rowwise，有一个约束是它按行分组。但是，这里没有那个约束。因此，它不会在每个组的常规列中列出
你也可以使用table 和unnest_wider df %>% group_by(group1, group2) %>% summarise(count = list(table(c_across(everything()))), .groups = 'drop') %>% unnest_wider(count)
感谢@akrun f pi r 的解释。明白了。

【解决方案3】：

使用data.table

library(data.table)
melt(setDT(df), id.var = c('group1', 'group2'))[, .(n = .N),
    .(group1, group2, value)]

-输出

    group1 group2 value n
1:   High   male   yes 3
2:   High female   yes 2
3:    Low female   yes 4
4:    Low   male    no 1
5:    Low female    no 2
6:   High   male    no 3
7:    Low   male   yes 2
8:   High female    no 1

有了base R，我们可以使用by和table

by(df[3:5], df[1:2], function(x) table(unlist(x)))

【讨论】：