regex_funcs {RCLabels}

Find or replace row or column labels that match a regular expression

Description

match_by_pattern() tells whether row or column labels match a regular expression. Internally, grepl() decides whether a match occurs. replace_by_pattern() replaces portions of row of column labels when a regular expression is matched. Internally, gsub() performs the replacements.

Usage

match_by_pattern(
  labels,
  regex_pattern,
  pieces = "all",
  prepositions = RCLabels::prepositions_list,
  notation = RCLabels::bracket_notation,
  ...
)

replace_by_pattern(
  labels,
  regex_pattern,
  replacement,
  pieces = "all",
  prepositions = RCLabels::prepositions_list,
  notation = RCLabels::bracket_notation,
  ...
)

Arguments

labels

The row and column labels to be modified.

regex_pattern

The regular expression pattern to determine matches and replacements. Consider using Hmisc::escapeRegex() to escape regex_pattern before calling this function.

pieces

The pieces of row or column labels to be checked for matches or replacements. See details.

prepositions

A vector of strings that count as prepositions. Default is RCLabels::prepositions_list. Used to detect prepositional phrases if pieces are to be interpreted as prepositions.

notation

The notation used in labels. Default is RCLabels::bracket_notation.

...

Other arguments passed to grepl() or gsub(), such as ignore.case, perl, fixed, or useBytes. See examples.

replacement

For replace_by_pattern(), the string that replaces all matches to regex_pattern.

Details

By default (pieces = "all"), complete labels (as strings) are checked for matches and replacements. If pieces == "pref" or pieces == "suff", only the prefix or the suffix is checked for matches and replacements. Alternatively, pieces = "noun" or ⁠pieces = <<preposition>>⁠ indicate that only specific pieces of labels are to be checked for matches and replacements. When ⁠pieces = <<preposition>>⁠, only the object of ⁠<<preposition>>⁠ is checked for matches and replacement.

pieces can be a vector, indicating multiple pieces to be checked for matches and replacements. But if any of the pieces are "all", all pieces are checked and replaced. If pieces is "pref" or "suff", only one can be specified.

Value

A logical vector of same length as labels, where TRUE indicates a match was found and FALSE indicates otherwise.

Examples

labels <- c("Production [of b in c]", "d [of Coal in f]", "g [of h in USA]")
# With default `pieces` argument, matching is done for whole labels.
match_by_pattern(labels, regex_pattern = "Production")
match_by_pattern(labels, regex_pattern = "Coal")
match_by_pattern(labels, regex_pattern = "USA")
# Check beginnings of labels
match_by_pattern(labels, regex_pattern = "^Production")
# Check at ends of labels: no match.
match_by_pattern(labels, regex_pattern = "Production$")
# Can match on nouns or prepositions.
match_by_pattern(labels, regex_pattern = "Production", pieces = "noun")
# Gives FALSE, because "Production" is a noun.
match_by_pattern(labels, regex_pattern = "Production", pieces = "in")