42 lines
1.4 KiB
Markdown
42 lines
1.4 KiB
Markdown
---
|
|
title: levenshteinDistance
|
|
tags: algorithm,advanced
|
|
---
|
|
|
|
Calculates the [Levenshtein distance](https://en.wikipedia.org/wiki/Levenshtein_distance) between two strings.
|
|
|
|
Calculates the number of changes (substitutions, deletions or additions) required to convert `string1` to `string2`.
|
|
Can also be used to compare two strings as shown in the second example.
|
|
|
|
```js
|
|
const levenshteinDistance = (string1, string2) => {
|
|
if (string1.length === 0) return string2.length;
|
|
if (string2.length === 0) return string1.length;
|
|
let matrix = Array(string2.length + 1)
|
|
.fill(0)
|
|
.map((x, i) => [i]);
|
|
matrix[0] = Array(string1.length + 1)
|
|
.fill(0)
|
|
.map((x, i) => i);
|
|
for (let i = 1; i <= string2.length; i++) {
|
|
for (let j = 1; j <= string1.length; j++) {
|
|
if (string2[i - 1] === string1[j - 1]) {
|
|
matrix[i][j] = matrix[i - 1][j - 1];
|
|
} else {
|
|
matrix[i][j] = Math.min(
|
|
matrix[i - 1][j - 1] + 1,
|
|
matrix[i][j - 1] + 1,
|
|
matrix[i - 1][j] + 1
|
|
);
|
|
}
|
|
}
|
|
}
|
|
return matrix[string2.length][string1.length];
|
|
};
|
|
```
|
|
|
|
```js
|
|
levenshteinDistance('30-seconds-of-code','30-seconds-of-python-code'); // 7
|
|
const compareStrings = (string1,string2) => (100 - levenshteinDistance(string1,string2) / Math.max(string1.length,string2.length));
|
|
compareStrings('30-seconds-of-code', '30-seconds-of-python-code'); // 99.72 (%)
|
|
``` |