stringdist
- 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 vectorsstringsim
computes a string similarity between 0 and 1, based onstringdist
amatch
is a fuzzy matching equivalent of R's nativematch
functionain
is a fuzzy matching equivalent of R's native%in%
operatorseq_dist
,seq_distmatrix
,seq_amatch
andseq_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 morecharacter
vectors.seq_qrams()
tabulates the qgrams (somtimes called ngrams) in one or moreinteger
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.
C API
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.