Extract variable names or indices of a specific class

Source: R/utils.R

The find_class() extracts variable information having a certain class from an object inheriting data.frame.

find_class(
  df,
  type = c("numerical", "categorical", "categorical2", "date_categorical",
    "date_categorical2"),
  index = TRUE
)

Arguments

df

a data.frame or objects inheriting from data.frame

type

character. Defines a group of classes to be searched. "numerical" searches for "numeric" and "integer" classes, "categorical" searches for "factor" and "ordered" classes. "categorical2" adds "character" class to "categorical". "date_categorical" adds result of "categorical2" and "Date", "POSIXct". "date_categorical2" adds result of "categorical" and "Date", "POSIXct".

index

logical. If TRUE is return numeric vector that is variables index. and if FALSE is return character vector that is variables name. default is TRUE.

Value

character vector or numeric vector. The meaning of vector according to data type is as follows.

  • character vector : variables name

  • numeric vector : variables index

See also

get_class.

Examples

# data.frame
find_class(iris, "numerical")
#> [1] 1 2 3 4
find_class(iris, "numerical", index = FALSE)
#> [1] "Sepal.Length" "Sepal.Width"  "Petal.Length" "Petal.Width" 
find_class(iris, "categorical")
#> [1] 5
find_class(iris, "categorical", index = FALSE)
#> [1] "Species"

# tbl_df
find_class(ggplot2::diamonds, "numerical")
#> [1]  1  5  6  7  8  9 10
find_class(ggplot2::diamonds, "numerical", index = FALSE)
#> [1] "carat" "depth" "table" "price" "x"     "y"     "z"    
find_class(ggplot2::diamonds, "categorical")
#> [1] 2 3 4
find_class(ggplot2::diamonds, "categorical", index = FALSE)
#> [1] "cut"     "color"   "clarity"

# type is "categorical2"
iris2 <- data.frame(iris, char = "chars",
                    stringsAsFactors = FALSE)
find_class(iris2, "categorical", index = FALSE)
#> [1] "Species"
find_class(iris2, "categorical2", index = FALSE)
#> [1] "Species" "char"