我正在写一个函数dplyr::_join两个数据框by不同的列，第一个数据帧的列名称动态指定为函数参数。我相信我需要使用rlang准引用/元编程，但未能找到可行的解决方案。我很感激任何建议！
library(dplyr)
library(rlang)
library(palmerpenguins)
# Create a smaller dataset
penguins <-
penguins %>%
group_by(species) %>%
slice_head(n = 4) %>%
ungroup()
# Create a colors dataset
penguin_colors <-
tibble(
type = c("Adelie", "Chinstrap", "Gentoo"),
color = c("orange", "purple", "green")
)
# Without function --------------------------------------------------------
# Join works with character vectors
left_join(
penguins, penguin_colors, by = c("species" = "type")
)
#> # A tibble: 12 x 9
#> species island bill_length_mm bill_depth_mm flipper_length_… body_mass_g
#> <chr> <fct> <dbl> <dbl> <int> <int>
#> 1 Adelie Torge… 39.1 18.7 181 3750
#> 2 Adelie Torge… 39.5 17.4 186 3800
#> 3 Adelie Torge… 40.3 18 195 3250
#> 4 Adelie Torge… NA NA NA NA
#> 5 Chinst… Dream 46.5 17.9 192 3500
#> 6 Chinst… Dream 50 19.5 196 3900
#> 7 Chinst… Dream 51.3 19.2 193 3650
#> 8 Chinst… Dream 45.4 18.7 188 3525
#> 9 Gentoo Biscoe 46.1 13.2 211 4500
#> 10 Gentoo Biscoe 50 16.3 230 5700
#> 11 Gentoo Biscoe 48.7 14.1 210 4450
#> 12 Gentoo Biscoe 50 15.2 218 5700
#> # … with 3 more variables: sex <fct>, year <int>, color <chr>
# Join works with data-variable and character vector
left_join(
penguins, penguin_colors, by = c(species = "type")
)
#> # A tibble: 12 x 9
#> species island bill_length_mm bill_depth_mm flipper_length_… body_mass_g
#> <chr> <fct> <dbl> <dbl> <int> <int>
#> 1 Adelie Torge… 39.1 18.7 181 3750
#> 2 Adelie Torge… 39.5 17.4 186 3800
#> 3 Adelie Torge… 40.3 18 195 3250
#> 4 Adelie Torge… NA NA NA NA
#> 5 Chinst… Dream 46.5 17.9 192 3500
#> 6 Chinst… Dream 50 19.5 196 3900
#> 7 Chinst… Dream 51.3 19.2 193 3650
#> 8 Chinst… Dream 45.4 18.7 188 3525
#> 9 Gentoo Biscoe 46.1 13.2 211 4500
#> 10 Gentoo Biscoe 50 16.3 230 5700
#> 11 Gentoo Biscoe 48.7 14.1 210 4450
#> 12 Gentoo Biscoe 50 15.2 218 5700
#> # … with 3 more variables: sex <fct>, year <int>, color <chr>
# Join does NOT work with character vector and data-variable
left_join(
penguins, penguin_colors, by = c(species = type)
)
#> Error in standardise_join_by(by, x_names = x_names, y_names = y_names): object 'type' not found
# With function -----------------------------------------------------------
# Version 1: Without tunneling
add_colors <- function(data, var) {
left_join(
data, penguin_colors, by = c(var = "type")
)
}
add_colors(penguins, species)
#> Error: Join columns must be present in data.
#> x Problem with `var`.
add_colors(penguins, "species")
#> Error: Join columns must be present in data.
#> x Problem with `var`.
# Version 2: With tunneling
add_colors <- function(data, var) {
left_join(
data, penguin_colors, by = c("{{var}}" = "type")
)
}
add_colors(penguins, species)
#> Error: Join columns must be present in data.
#> x Problem with `{{var}}`.
add_colors(penguins, "species")
#> Error: Join columns must be present in data.
#> x Problem with `{{var}}`.
# Version 2: With tunneling and glue syntax
add_colors <- function(data, var) {
left_join(
data, penguin_colors, by = c("{{var}}" := "type")
)
}
add_colors(penguins, species)
#> Error: `:=` can only be used within a quasiquoted argument
add_colors(penguins, "species")
#> Error: `:=` can only be used within a quasiquoted argument
Created on 2020-10-05 by the reprex package https://reprex.tidyverse.org (v0.3.0)
以下是我查阅的相关资源：
- 将“rlang”准引用与“dplyr::_join”函数一起使用 https://stackoverflow.com/questions/58846126/using-rlang-quasiquotation-with-dplyr-join-functions
- https://dplyr.tidyverse.org/reference/join.html https://dplyr.tidyverse.org/reference/join.html
- https://speakerdeck.com/lionelhenry/interactivity-and-programming-in-the-tidyverse https://speakerdeck.com/lionelhenry/interactivity-and-programming-in-the-tidyverse
- https://dplyr.tidyverse.org/articles/programming.html https://dplyr.tidyverse.org/articles/programming.html
感谢您的建议。
