How to show levels or labels of a dataframe using pipe in R-CodePudding

I have no problem showing the levels of data dataframe using attributes(data$sex)$levels.

But, how to do it with pipe? I tried data %>% attributes(sex)$levels but it gives an error.

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
set.seed(22)
data <- data.frame(age = floor(rnorm(6,25,10)), 
                   sex = gl(2,1,6, labels = c("f","m")))
var.labels <- c(age = "Age in Years", 
                sex = "Sex of the participant")
tibble::as_tibble(data)
#> # A tibble: 6 × 2
#>     age sex  
#>   <dbl> <fct>
#> 1    19 f    
#> 2    49 m    
#> 3    35 f    
#> 4    27 m    
#> 5    22 f    
#> 6    43 m

attributes(data$sex)$levels
#> [1] "f" "m"

# How to do it using pipe?
data %>% attributes(sex)$levels
#> Error in `$`(., attributes(sex), levels): 3 arguments passed to '$' which requires 2
Created on 2022-08-19 by the reprex package (v2.0.1)

CodePudding user response：

Wrap with {} and use .$ to extract the column

library(dplyr)
data %>%
   {attributes(.$sex)$levels}
[1] "f" "m"

Or use the standard dplyr methods

data %>% 
  pull(sex) %>% 
  levels
[1] "f" "m"

Or use exposition operator (%$%) from magrittr

library(magrittr)
data %$% 
  attributes(sex)$levels
[1] "f" "m"

CodePudding user response：

We can use Base R pip

data |> with(attributes(sex)$levels)

[1] "f" "m"