wildcard (version 1.0.3)

wildcard: Function wildcard

Description

Main function of the package. Evaluate a wildcard to fill in or expand a data frame. Copied and modified from remakeGenerator::evaluate() package under GPL-3: https://github.com/wlandau/remakeGenerator

Usage

wildcard(df, rules = NULL, wildcard = NULL, values = NULL,
  expand = TRUE)

Arguments

df

data frame

rules

list with names a wildcards and elements as vectors of values to substitute in place of the wildcards.

wildcard

character scalar, a wildcard found in a data frame

values

vector of values to substitute in place of a wildcard

expand

logical, whether to expand the rows of the data frame to substitute each value for each wildcard in turn. If FALSE, no new rows will be added to df when the values are substituted in place of wildcards. Can be a vector of length length(rules) if using the rules argument.

Examples

# NOT RUN {
myths <- data.frame(
  myth = c('Bigfoot', 'UFO', 'Loch Ness Monster'), 
  claim = c('various', 'day', 'day'), 
 note = c('various', 'pictures', 'reported day'))
wildcard(myths, wildcard = 'day', values = c('today', 'yesterday'))
wildcard(myths, wildcard = 'day', values = c('today', 'yesterday'), expand = FALSE)
locations <- data.frame(
  myth = c('Bigfoot', 'UFO', 'Loch Ness Monster'),
  origin = 'where')
rules <- list(
  where = c('North America', 'various', 'Scotland'),
  UFO = c('spaceship', 'saucer'))
wildcard(locations, rules = rules, expand = c(FALSE, TRUE))
numbers <- data.frame(x = 4, y = 3, z = 4444, w = 4.434)
wildcard(numbers, wildcard = 4, values = 7)
# Wildcards should not also be replacement values.
# Otherwise, the output will be strange
# and will depend on the order of the wildcards.
# }
# NOT RUN {
df <- data.frame(x = "a", y = "b")
rules <- list(a = letters[1:3], b = LETTERS[1:3])
wildcard(df, rules = rules)
# }