R: 正确应用R中的轴心函数

我会这样做的:

library(tidyr)
library(dplyr)
#> 
#> Attaching package: 'dplyr'
#> The following objects are masked from 'package:stats':
#> 
#>     filter, lag
#> The following objects are masked from 'package:base':
#> 
#>     intersect, setdiff, setequal, union
structure(list(col = c("A", "B", "C"), `2000-01-01` = c(86L, 
                                                        43L, 73L), `2000-01-02` = c(99L, 77L, 12L)), class = "data.frame", row.names = c(NA, 
                                                                                                                                         -3L)
    ) %>% 
    pivot_longer(-col, names_to = 'date', values_to = 'count') %>% 
    arrange(date, col)
#> # A tibble: 6 × 3
#>   col   date       count
#>   <chr> <chr>      <int>
#> 1 A     2000-01-01    86
#> 2 B     2000-01-01    43
#> 3 C     2000-01-01    73
#> 4 A     2000-01-02    99
#> 5 B     2000-01-02    77
#> 6 C     2000-01-02    12

^{创建于2022-12-09 reprex v2.0.2}