# trigram
[](https://travis-ci.org/ijt/trigram)
[](https://raw.githubusercontent.com/ijt/trigram/master/LICENSE)
[](https://docs.rs/trigram)
This Rust crate contains functions for fuzzy string matching.
It exports two functions. The `similarity` function returns the similarity of
two strings, and the `find_words_iter` function returns an iterator of matches
for a smaller string (`needle`) in a larger string (`haystack`).
The similarity of strings is computed based on their trigrams, meaning their
3-character substrings: https://en.wikipedia.org/wiki/Trigram.
## Trying it out
Here is how to run the examples:
```
$ cargo run --example similarity color colour
...
0.44444445
$ cargo run --example find_words_iter
bufalo
buffalow
Bungalo
biffalo
buffaloo
huffalo
snuffalo
fluffalo
```
## Usage
Add this to your `Cargo.toml`:
```toml
[dependencies]
trigram = "0.2.2"
```
and call it like this:
```rust
use trigram::similarity;
fn main() {
println!("{}", similarity(&"rustacean", &"crustacean"));
}
```
## Background
The `similarity` function in this crate is a reverse-engineered approximation
of the `similarity` function in the Postgresql pg\_trgm extension:
https://www.postgresql.org/docs/9.1/pgtrgm.html. It gives exactly the same
answers in many cases, but may disagree in others (none known). If you find a
case where the answers don't match, please file an issue about it!
A good introduction to the Postgres version of this is given on Stack Overflow:
https://stackoverflow.com/a/43161051/484529.