[英]Access names of columns passed to map()
如何訪問purrr :: map()的輸入名稱?
這段代碼:
library(tidyverse)
library(janitor)
diamonds %>%
select(cut, color) %>%
map( function(x) janitor::tabyl(x) )
輸出:
$cut
x n percent
1 Fair 1610 0.02984798
2 Good 4906 0.09095291
3 Very Good 12082 0.22398962
4 Premium 13791 0.25567297
5 Ideal 21551 0.39953652
$color
x n percent
1 D 6775 0.12560252
2 E 9797 0.18162773
3 F 9542 0.17690026
4 G 11292 0.20934372
5 H 8304 0.15394883
6 I 5422 0.10051910
7 J 2808 0.05205784
但我試圖訪問傳遞給map的列的名稱。 像這樣的東西(偽代碼):
diamonds %>%
select(cut, color) %>%
map( function(x) { table_1 <- janitor::tabyl(x)
table_1$column_name <- SOMEHOW_EXTRACT_NAME(x)
}
)
要在列中輸入具有輸入名稱的所需輸出:
$cut
x n percent column_name
1 Fair 1610 0.02984798 cut
2 Good 4906 0.09095291 cut
3 Very Good 12082 0.22398962 cut
4 Premium 13791 0.25567297 cut
5 Ideal 21551 0.39953652 cut
$color
x n percent column_name
1 D 6775 0.12560252 color
2 E 9797 0.18162773 color
3 F 9542 0.17690026 color
4 G 11292 0.20934372 color
5 H 8304 0.15394883 color
6 I 5422 0.10051910 color
7 J 2808 0.05205784 color
使用imap
,您可以使用它作為第二個參數訪問該名稱:
diamonds %>%
select(cut, color) %>%
imap(
function(x, name) {
table_1 <- janitor::tabyl(x)
table_1$column_name <- name
table_1
}
)
#$cut
# x n percent column_name
#1 Fair 1610 0.02984798 cut
#2 Good 4906 0.09095291 cut
#3 Very Good 12082 0.22398962 cut
#4 Premium 13791 0.25567297 cut
#5 Ideal 21551 0.39953652 cut
#$color
# x n percent column_name
#1 D 6775 0.12560252 color
#2 E 9797 0.18162773 color
#3 F 9542 0.17690026 color
#4 G 11292 0.20934372 color
#5 H 8304 0.15394883 color
#6 I 5422 0.10051910 color
#7 J 2808 0.05205784 color
要么
diamonds %>%
select(cut, color) %>%
imap( ~ { janitor::tabyl(.x) %>% mutate(column_name = .y) })
簡而言之。
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