freq {quest}

Univariate Frequency Table

Description

freq creates univariate frequency tables similar to table. It differs from table by allowing for custom sorting by something other than the alphanumerics of the unique values as well as returning an atomic vector rather than a 1D-array.

Usage

freq(
  x,
  exclude = if (useNA == "no") c(NA, NaN),
  useNA = "always",
  prop = FALSE,
  sort = "frequency",
  decreasing = TRUE,
  na.last = TRUE
)

Arguments

x

atomic vector or list vector. If not a vector, it will be coerced to a vector via as.vector.

exclude

unique values of x to exclude from the returned table. If NULL, then missing values are always included in the returned table. See table for documentation on the same argument.

useNA

character vector of length 1 specifying how to handle missing values (i.e., whether to include NA as an element in the returned table). There are three options: 1) "no" = don't include missing values in the table, 2) "ifany" = include missing values if there are any, 3) "always" = include missing values in the table, regardless of whether there are any or not. See table for documentation on the same argument.

prop

logical vector of length 1 specifying whether the returned table should include counts (FALSE) or proportions (TRUE). If NAs are excluded (e.g., useNA = "no" or exclude = c(NA, NaN)), then the proportions will be based on the number of observed elements.

sort

character vector of length 1 specifying how the returned table will be sorted. There are three options: 1) "frequency" = the frequency of the unique values in x, 2) "position" = the position when each unique value first appears in x, 3) "alphanum" = alphanumeric ordering of the unique values in x (the sorting used by table). When "frequency" is specified and there are ties, then the ties are sorted alphanumerically.

decreasing

logical vector of length 1 specifying whether the table should be sorted in decreasing (TRUE) or increasing (FALSE) order.

na.last

logical vector of length 1 specifying whether the table should have NAs last or in whatever position they end up at. This argument is only relevant if NAs exist in x and are included in the table (e.g., useNA = "always" or exclude = NULL).

Details

The name for the table element giving the frequency of missing values is "(NA)". This is different from table where the name is NA_character_. This change allows for the sorting of tables that include missing values, as subsetting in R is not possible with NA_character_ names. In future versions of the package, this might change as it should be possible to avoid this issue by subetting with a logical vector or integer indices instead of names. However, it is convenient to be able to subset the return object fully by names.

Value

numeric vector of frequencies as either counts (if prop = FALSE) or proportions (if prop = TRUE) with the unique values of x as names (missing values have name = "(NA)"). Note, this is different from table, which returns a 1D-array and has class "table".

See Also

freqs freq_by freqs_by table

Examples

freq(c(mtcars$"carb", NA, NA, mtcars$"gear"), prop = FALSE,
   sort = "frequency", decreasing = TRUE, na.last = TRUE)
freq(c(mtcars$"carb", NA, NA, mtcars$"gear"), prop = FALSE,
   sort = "frequency", decreasing = TRUE, na.last = FALSE)
freq(c(mtcars$"carb", NA, NA, mtcars$"gear"), prop = TRUE,
   sort = "frequency", decreasing = FALSE, na.last = TRUE)
freq(c(mtcars$"carb", NA, NA, mtcars$"gear"), prop = TRUE,
   sort = "frequency", decreasing = FALSE, na.last = FALSE)
freq(c(mtcars$"carb", NA, NA, mtcars$"gear"), prop = FALSE,
   sort = "position", decreasing = TRUE, na.last = TRUE)
freq(c(mtcars$"carb", NA, NA, mtcars$"gear"), prop = FALSE,
   sort = "position", decreasing = TRUE, na.last = FALSE)
freq(c(mtcars$"carb", NA, NA, mtcars$"gear"), prop = TRUE,
   sort = "position", decreasing = FALSE, na.last = TRUE)
freq(c(mtcars$"carb", NA, NA, mtcars$"gear"), prop = TRUE,
   sort = "position", decreasing = FALSE, na.last = FALSE)
freq(c(mtcars$"carb", NA, NA, mtcars$"gear"), prop = FALSE,
   sort = "alphanum", decreasing = TRUE, na.last = TRUE)
freq(c(mtcars$"carb", NA, NA, mtcars$"gear"), prop = FALSE,
   sort = "alphanum", decreasing = TRUE, na.last = FALSE)
freq(c(mtcars$"carb", NA, NA, mtcars$"gear"), prop = TRUE,
   sort = "alphanum", decreasing = FALSE, na.last = TRUE)
freq(c(mtcars$"carb", NA, NA, mtcars$"gear"), prop = TRUE,
   sort = "alphanum", decreasing = FALSE, na.last = FALSE)