Merge pull request #611 from kriadmin/lev-dist

[ADD] levenshteinDistance

snippets_archive/levenshteinDistance.md

@@ -0,0 +1,32 @@
+### levenshteinDistance
+
+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 (%)
+```

test/levenshteinDistance/levenshteinDistance.js

@@ -0,0 +1,18 @@
+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];
+};
+module.exports = levenshteinDistance;

test/levenshteinDistance/levenshteinDistance.test.js

@@ -0,0 +1,13 @@
+const test = require('tape');
+const levenshteinDistance = require('./levenshteinDistance.js');
+
+test('Testing levenshteinDistance', (t) => {
+  //For more information on all the methods supported by tape
+  //Please go to https://github.com/substack/tape
+  t.true(typeof levenshteinDistance === 'function', 'levenshteinDistance is a Function');
+  //t.deepEqual(levenshteinDistance(args..), 'Expected');
+  //t.equal(levenshteinDistance(args..), 'Expected');
+  //t.false(levenshteinDistance(args..), 'Expected');
+  //t.throws(levenshteinDistance(args..), 'Expected');
+  t.end();
+});

test/testlog

@@ -1,4 +1,4 @@
-Test log for: Mon Feb 26 2018 15:06:03 GMT+0530 (India Standard Time)
+Test log for: Mon Feb 26 2018 15:00:57 GMT+0530 (India Standard Time)
 
 > 30-seconds-of-code@0.0.2 test R:\github\30-seconds-of-code
 > tape test/**/*.test.js | tap-spec
@@ -538,12 +538,6 @@ Test log for: Mon Feb 26 2018 15:06:03 GMT+0530 (India Standard Time)
     √ Returns own methods
     √ Returns own and inherited methods
 
-  Testing fuzzySearch
-
-    √ fuzzySearch is a Function
-    √ Provided examples work
-    √ Provided examples work
-
   Testing gcd
 
     √ gcd is a Function
@@ -904,10 +898,6 @@ Test log for: Mon Feb 26 2018 15:06:03 GMT+0530 (India Standard Time)
 
     √ isSet is a Function
 
-  Testing isSimilar
-
-    √ isSimilar is a Function
-
   Testing isSorted
 
     √ isSorted is a Function
@@ -999,6 +989,10 @@ Test log for: Mon Feb 26 2018 15:06:03 GMT+0530 (India Standard Time)
     √ Returns the least common multiple of two or more numbers.
     √ Returns the least common multiple of two or more numbers.
 
+  Testing levenshteinDistance
+
+    √ levenshteinDistance is a Function
+
   Testing longestItem
 
     √ longestItem is a Function
@@ -1527,6 +1521,11 @@ Test log for: Mon Feb 26 2018 15:06:03 GMT+0530 (India Standard Time)
     √ spreadOver is a Function
     √ Takes a variadic function and returns a closure that accepts an array of arguments to map to the inputs of the function.
 
+  Testing stableSort
+
+    √ stableSort is a Function
+    √ Array is properly sorted
+
   Testing standardDeviation
 
     √ standardDeviation is a Function
@@ -1910,13 +1909,13 @@ Test log for: Mon Feb 26 2018 15:06:03 GMT+0530 (India Standard Time)
     √ Runs the function provided
     √ Runs promises in series
     √ Sends a GET request
-    √ Sends a POST request
     √ Works as expecting, passing arguments properly
+    √ Sends a POST request
     √ Works with multiple promises
 
 
-  total:     974
-  passing:   974
-  duration:  2.6s
+  total:     973
+  passing:   973
+  duration:  3s