Generate a Histogram for a character or factor variable.

Generate a histogram for a character or factor variable. This graph is intended to quickly provide the researcher with a quick, yet thorough representation of the continuous variable. The additional annotations may not be desired for publication-quality plots.

Usage

histogram_discrete(
  d_observed,
  variable_name,
  levels_to_exclude = character(0),
  main_title = base::gsub("_", " ", variable_name, perl = TRUE),
  x_title = NULL,
  y_title = "Number of Included Records",
  text_size_percentage = 6,
  bin_width = 1L,
  font_base_size = 12
)

Arguments

d_observed

The data.frame with the variable to graph.

variable_name

The name of the variable to graph. character.

levels_to_exclude

An array of of the levels to be excluded from the histogram. Pass an empty variable (ie, character(0)) if all levels are desired; this is the default. character.

main_title

The desired title on top of the graph. Defaults to variable_name, with underscores replaced with spaces. If no title is desired, pass a value of NULL. character.

x_title

The desired title on the x-axis. Defaults to the number of included records. If no axis title is desired, pass a value of NULL. character.

y_title

The desired title on the y-axis. Defaults to “Frequency”. If no axis title is desired, pass a value of NULL. character.

text_size_percentage

The size of the percentage values on top of the bars. character.

bin_width

(This parameter is included for compatibility with other graphing functions. It should always be 1 for discrete and boolean variables.)

font_base_size

Sets font size through ggplot2's theme.

Value

Returns a histogram as a ggplot2 object.

Examples

ds <-
  datasets::infert |> 
  tibble::as_tibble()
  
# Simulate missing values
ds$education[c(3:9, 20:29, 80:95)] <- NA
ds$age[      c(5:8, 14:22, 70:85)] <- NA

  
# Don't run graphs on a headless machine without any the basic graphics packages installed.
if( require(grDevices) ) {
  # Simple Cases
  histogram_discrete(
    d_observed     = ds, 
    variable_name  = "education"
  )
  histogram_discrete(
    d_observed     = ds, 
    variable_name  = "age"
  )
  
  # Variable has no nonmissing values
  histogram_discrete(
    d_observed     = ds[100:200, ], 
    variable_name  = "age"
  )

  # Adjust cosmetics of bar-graph/histogram
  histogram_discrete(
    d_observed         = ds, 
    variable_name      = "age",
    levels_to_exclude  = c(21:29, 40:44),    # Show only subjects in their 30s.
    main_title         = "Frequency of Subjects, by Age"
  )
}