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  • Approximate matching and string distance calculations for R.
  • All distance and matching operations are system- and encoding-independent.
  • Built for speed, using openMP for parallel computing.

The package offers the following main functions:

  • stringdist computes pairwise distances between two input character vectors (shorter one is recycled)
  • stringdistmatrix computes the distance matrix for one or two vectors
  • stringsim computes a string similarity between 0 and 1, based on stringdist
  • amatch is a fuzzy matching equivalent of R's native match function
  • ain is a fuzzy matching equivalent of R's native %in% operator
  • seq_dist, seq_distmatrix, seq_amatch and seq_ain for distances between, and matching of integer sequences.

These functions are built upon C-code that re-implements some common (weighted) string distance functions. Distance functions include:

  • Hamming distance;
  • Levenshtein distance (weighted)
  • Restricted Damerau-Levenshtein distance (weighted, a.k.a. Optimal String Alignment)
  • Full Damerau-Levenshtein distance
  • Longest Common Substring distance
  • Q-gram distance
  • cosine distance for q-gram count vectors (= 1-cosine similarity)
  • Jaccard distance for q-gram count vectors (= 1-Jaccard similarity)
  • Jaro, and Jaro-Winkler distance
  • Soundex-based string distance

Also, there are some utility functions:

  • qgrams() tabulates the qgrams in one or more character vectors.
  • seq_qrams() tabulates the qgrams (somtimes called ngrams) in one or more integer vectors.
  • phonetic() computes phonetic codes of strings (currently only soundex)
  • printable_ascii() is a utility function that detects non-printable ascii or non-ascii characters.


Some of stringdist's underlying C functions can be called directly from C code in other packages. The description of the API can be found by either typing ?stringdist_api in the R console or open the vignette directly as follows:

vignette("stringdist_C-Cpp_api", package="stringdist")

Examples of packages that link to stringdist can be found here and here.


  • A paper on stringdist has been published in the R-journal
  • Slides of a talk given at te useR!2014 conference.

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Last Published

September 9th, 2021

Functions in stringdist (0.9.8)