R haven as_factor 將標記向量轉換為因子

# S3 method for data.frame
as_factor(x, ..., only_labelled = TRUE)

# S3 method for haven_labelled
as_factor(
  x,
  levels = c("default", "labels", "values", "both"),
  ordered = FALSE,
  ...
)

# S3 method for labelled
as_factor(
  x,
  levels = c("default", "labels", "values", "both"),
  ordered = FALSE,
  ...
)

x <- labelled(sample(5, 10, replace = TRUE), c(Bad = 1, Good = 5))

# Default method uses values where available
as_factor(x)
#>  [1] 3   4   4   Bad 2   3   Bad 3   Bad 3  
#> Levels: Bad 2 3 4 Good
# You can also extract just the labels
as_factor(x, levels = "labels")
#>  [1] <NA> <NA> <NA> Bad  <NA> <NA> Bad  <NA> Bad  <NA>
#> Levels: Bad Good
# Or just the values
as_factor(x, levels = "values")
#>  [1] 3 4 4 1 2 3 1 3 1 3
#> Levels: 1 2 3 4
# Or combine value and label
as_factor(x, levels = "both")
#>  [1] 3       4       4       [1] Bad 2       3       [1] Bad 3      
#>  [9] [1] Bad 3      
#> Levels: [1] Bad 2 3 4 [5] Good

# as_factor() will preserve SPSS missing values from values and ranges
y <- labelled_spss(1:10, na_values = c(2, 4), na_range = c(8, 10))
as_factor(y)
#>  [1] 1  2  3  4  5  6  7  8  9  10
#> Levels: 1 2 3 4 5 6 7 8 9 10
# use zap_missing() first to convert to NAs
zap_missing(y)
#>  [1]  1 NA  3 NA  5  6  7 NA NA NA
#> attr(,"class")
#> [1] "haven_labelled"
as_factor(zap_missing(y))
#>  [1] 1    <NA> 3    <NA> 5    6    7    <NA> <NA> <NA>
#> Levels: 1 3 5 6 7