是否有 R 函数显示数据集中特定列中每个唯一出现的频率？

Question

为了简单起见，我创建了小型虚拟数据集。

library(tidyverse)
library(lubridate)

myDF <- tibble(country = rep(c("UK", "US"), each = 3),
              date = c("2020-01-01", "2020-02-01", "2020-02-01", "2020-03-01",
                       "2020-03-01", "2020-03-01"))
myDF <- myDF %>% mutate(date = as_date(date))

  country date      
  <chr>   <date>    
1 UK      2020-01-01
2 UK      2020-02-01
3 UK      2020-02-01
4 US      2020-03-01
5 US      2020-03-01
6 US      2020-03-01

我知道 unique() 函数可用于查找在日期列。

unique(myDF$date) # the unique values
length(unique(myDF$date)) # number of unique values

但是我如何创建一个小的 table 输出来显示数据集中特定列（即日期）中每个唯一出现的频率？我正在寻找这样的东西：

   myDF$date  freq
"2020-01-01"     1
"2020-02-01"     2
"2020-03-01"     3

Answer 1

You can do something like 


  library(dplyr)
myDF %>% count(date, name = 'freq')

是否有 R 函数显示数据集中特定列中每个唯一出现的频率？

Is there a R function which displays the frequency of each of unique occurrence in a specific column in a dataset?

r

lubridate

tidyverse