从基使用table（）函数和dplyr管道语法？

Question

下面是一些示例数据，它的输出是我想要得到的。

df <- tibble(id=c(rep("A",100),rep("B",100),rep("C",100)),
               val=c(rnorm(300,mean=500,sd=100))) %>%
  mutate(val_bin=cut(val,breaks=5))

table(df$id,df$val_bin)

输出：

    (210,325] (325,440] (440,554] (554,669] (669,784]
  A         4        22        55        18         1
  B         6        19        46        24         5
  C         3        23        44        22         8

Answer 1

我们可以选择感兴趣的列并应用表

library(dplyr)
df %>% 
    select(id, val_bin) %>%
    table

或者另一个选项是在{}中包装

df %>%
    {table(.$id, .$val_bin)}

在tidyverse中，获取所需的输出要复杂一些

library(dplyr)
library(tidyr)
df %>%
   count(id, val_bin) %>%
   pivot_wider(names_from = val_bin, values_from = n, values_fill = list(n = 0)) %>%
   column_to_rownames('id')
#   (214,338] (338,461] (461,584] (584,707] (707,831]
#A         5        30        44        20         1
#B         9        30        34        27         0
#C         8        28        43        20         1