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Normalize street names across languages

Source: R/preparer_word.R
normalize_street.Rd

Street names are written many ways for the same place: "Hauptstr.", "Hauptstrasse", "Haupt Strasse". normalize_street() collapses those variants to one canonical spelling so an address column matches on the street name rather than on its abbreviation. It normalizes Unicode, folds to ASCII, upper-cases, and cleans whitespace, then rewrites known street-type tokens from a multilingual dictionary.

Usage

normalize_street(
  x,
  lang = NULL,
  drop_house_numbers = FALSE,
  drop_stopwords = FALSE,
  dict = joinery::street_types,
  stopwords = joinery::street_stopwords
)

Arguments

x

A character vector containing street names or address fragments.

lang

Optional language code (e.g., "de", "en", "fr"). When provided, the dictionary is filtered to that language and safe language-specific suffix matching is enabled. It also restricts drop_stopwords to that language's particle list.

drop_house_numbers

Logical (default FALSE). When TRUE, drops any token beginning with a digit (house numbers like "12", "12A", "123B"), keeping only the street name. Applied after street-type replacement.

drop_stopwords

Logical (default FALSE). When TRUE, removes locative particles and articles (e.g. German AN DER, French DE LA) listed in stopwords, collapsing "An der Alster" to "ALSTER". When lang is given, only that language's particles are removed; otherwise the whole stopwords set is used.

dict

A dictionary of street-type definitions, typically street_types, containing the columns:

  • canonical: canonical uppercase form

  • variant: lowercased normalized variant form

  • type: "exact" or "suffix"

  • lang: ISO language code

stopwords

A street-stopword table, typically street_stopwords, with columns stopword (uppercase ASCII) and lang. Only consulted when drop_stopwords = TRUE.

Value

A character vector of normalized street names. NA inputs are preserved as NA. Rows reduced to nothing (e.g. a bare house number with drop_house_numbers = TRUE) become "".

Details

Returns text, so it sits where normalize_text() would in a pipeline, ahead of a token generator: street ~ normalize_street(lang = "de") + word_tokens().

Exact matches (e.g., "st", "rd.", "via") are always replaced. Suffix matches (e.g., German "strasse" endings or Dutch "straat") are applied only when lang is explicitly specified, which prevents unsafe substitutions such as rewriting the ending of "LINCOLN LANE".

Normalization steps include:

  • Unicode -> Latin transliteration and ASCII folding (stri_trans_general)

  • Conversion to uppercase

  • Removal of non-alphanumeric characters

  • Tokenization on spaces and per-token replacement

Exact variants are replaced verbatim with their canonical form. Suffix variants are replaced only when:

  • lang is specified, and

  • the token ends with a known variant suffix for that language.

See also

Other text normalizers: normalize_text(), strip_vowels()

Examples

normalize_street("Muellerstrasse", lang = "de")
#> [1] "MUELLERSTRASSE"
# "MUELLERSTRASSE"

normalize_street("123 Main St.")
#> [1] "123 MAIN STREET"
# "123 MAIN STREET"

normalize_street("Calle Mayor 3", lang = "es")
#> [1] "CALLE MAYOR 3"
# "CALLE MAYOR 3"

normalize_street("Hauptstr. 123A", lang = "de", drop_house_numbers = TRUE)
#> [1] "HAUPTSTRASSE"
# "HAUPTSTRASSE"

normalize_street("An der Alster 5", lang = "de",
                 drop_house_numbers = TRUE, drop_stopwords = TRUE)
#> [1] "ALSTER"
# "ALSTER"