以 tidy/dplyr 方式从数据帧/tibble 中提取单个值？

Question

我知道有几种从数据框/小标题中获取单个值的方法。

library(dplyr)

start_date <- tibble::tribble(
  ~StaffAbbrev, ~starting_date,
  "Alexander", "2021-08-23",
  "Cornelis", "2021-08-23",
  "Sotirchos", "2021-08-23",
  "Zhao", "2021-08-23",
  "Park", "2022-02-14",
  "Sarkar", "2022-04-04"
)

#Tidyverse way
Alexander_start_v1 <- start_date %>%
  filter(StaffAbbrev == "Alexander") %>%
  select(starting_date) %>%
  unlist() %>%
  unname() 

#Base R way
Alexander_start_v2=start_date$starting_date[start_date$StaffAbbrev=="Alexander"] 

是速记/更优雅/单行的 tidyverse 方式从数据帧/小标题中提取单个特定值吗？

Answer 1

以下是一些可能性：

library(dplyr)
library(tibble)
start_date %>% deframe %>% getElement("Alexander")
## [1] "2021-08-23"

library(dplyr)
library(tibble)
start_date %>% deframe %>% .[["Alexander"]]
## [1] "2021-08-23"

library(dplyr)
start_date %>% filter(StaffAbbrev == "Alexander") %>% pull
## [1] "2021-08-23"

library(dplyr)
library(magrittr)
start_date %>% filter(StaffAbbrev == "Alexander") %$% starting_date
## [1] "2021-08-23"

这是基本的 R 代码

with(start_date, starting_date[match("Alexander", StaffAbbrev)])
## [1] "2021-08-23"