Statistical Functions

modules/avg.js

@@ -0,0 +1,18 @@
+import isArrayLike from './_isArrayLike.js';
+import values from './values.js';
+import sum from './sum.js'
+
+// Return the average element (or element-based computation).
+export default function mean(obj, iteratee, context) {
+    if (!iteratee && _.isEmpty(obj)){
+        return 0;
+    }
+  var result = 0;
+  if (iteratee == null || typeof iteratee == 'number' && typeof obj[0] != 'object' && obj != null) {
+    obj = isArrayLike(obj) ? obj : values(obj);
+    result = sum(obj)/obj.length;
+  } else {
+    result = sum(obj, iteratee, context)/obj.length
+  }
+  return result;
+}

modules/index.js

@@ -198,3 +198,13 @@ export { default as chunk } from './chunk.js';
 // `underscore.js` and `index-default.js`.
 export { default as mixin } from './mixin.js';
 export { default } from './underscore-array-methods.js';
+
+//Statistical Function
+export { default as sum } from './sum.js';
+export { default as mean } from './avg.js';
+export { default as median } from './median.js';
+export { default as standardDeviation } from './standardDeviation.js';
+export { default as variance } from './variance.js';
+export { default as mode } from './mode.js';
+export { default as standardError } from './standardError.js';
+export { default as statRange } from './statRange.js';

modules/median.js

@@ -0,0 +1,28 @@
+import isArrayLike from './_isArrayLike.js';
+import values from './values.js';
+import cb from './_cb.js';
+import each from './each.js';
+import clone from './clone.js'
+import isNumber from './isNumber.js'
+
+// Return the median element (or element-based computation).
+export default function median(obj, iteratee, context) {
+    if (!iteratee && _.isEmpty(obj)){
+        return 0;
+    }
+  var tmpObj = [];
+  if (iteratee == null || typeof iteratee == 'number' && typeof obj[0] != 'object' && obj != null) {
+    obj = isArrayLike(obj) ? obj : values(obj);
+    tmpObj = clone(obj);
+    tmpObj.sort(function(f,s){return f-s;});
+  } else {
+    iteratee = cb(iteratee, context);
+    each(obj, function(v, index, list) {
+      computed = iteratee(v, index, list);
+      tmpObj.push(iteratee ? computed : v);
+      tmpObj.sort();
+    });
+  }
+
+  return tmpObj.length%2 ? tmpObj[Math.floor(tmpObj.length/2)] : (isNumber(tmpObj[tmpObj.length/2-1]) && isNumber(tmpObj[tmpObj.length/2])) ? (tmpObj[tmpObj.length/2-1]+tmpObj[tmpObj.length/2]) /2 : tmpObj[tmpObj.length/2-1];
+}

modules/mode.js

@@ -0,0 +1,35 @@
+import isArrayLike from './_isArrayLike.js';
+import values from './values.js';
+import sortBy from './sortBy.js'
+
+// Return the mode element (or element-based computation).
+export default function mode(obj, iteratee, context) {
+    if (!iteratee && _.isEmpty(obj)){
+        return 0;
+    }
+    var result = 0;
+    if (iteratee == null || typeof iteratee == 'number' && typeof obj[0] != 'object' && obj != null) {
+        obj = isArrayLike(obj) ? obj : values(obj);
+        obj = sortBy(obj);
+    }else{
+        obj = sortBy(tmpObj,iteratee,context);
+    }
+    var bestStreak = 1;
+    var bestElem = obj[0];
+    var currentStreak = 1;
+    var currentElem = obj[0];
+    for (var i = 1; i < obj.length; i++) {
+      if (obj[i-1] !== obj[i]) {
+        if (currentStreak > bestStreak) {
+          bestStreak = currentStreak;
+          bestElem = currentElem;
+        }
+        currentStreak = 0;
+        currentElem = obj[i];
+      }
+
+      currentStreak++;
+    }
+    result = currentStreak > bestStreak ? currentElem : bestElem;
+    return result
+}

modules/standardDeviation.js

@@ -0,0 +1,19 @@
+import isArrayLike from './_isArrayLike.js';
+import values from './values.js';
+import variance from './variance.js'
+
+// Return the standardDeviation element (or element-based computation).
+export default function standardDeviation(obj, iteratee, context) {
+    if (!iteratee && _.isEmpty(obj)){
+        return 0;
+    }
+    var result = 0;
+  if (iteratee == null || typeof iteratee == 'number' && typeof obj[0] != 'object' && obj != null) {
+    obj = isArrayLike(obj) ? obj : values(obj);
+    result = Math.sqrt(variance(obj));
+  } else {
+    result = Math.sqrt(variance(obj,iteratee,context));
+  }
+
+  return result;
+}

modules/standardError.js

@@ -0,0 +1,15 @@
+import isArrayLike from './_isArrayLike.js';
+import values from './values.js';
+import variance from './variance.js'
+export default function standardError(obj, iteratee, context) {
+    if (!iteratee && _.isEmpty(obj)) return 0;
+    var result = 0;
+    if (iteratee == null || typeof iteratee == 'number' && typeof obj[0] != 'object' && obj != null) {
+        obj = isArrayLike(obj) ? obj : values(obj);
+        result = Math.sqrt(variance(obj)/(obj.length-1));
+    }
+    else{
+        result = Math.sqrt(variance(obj,iterator,context)/(obj.length-1));
+    }
+    return result;
+}

modules/statRange.js

@@ -0,0 +1,6 @@
+import max from './max.js'
+import min from './min.js'
+
+export default function statRange(obj,iteratee,context){
+    return max(obj,iteratee,context) - min(obj,iteratee,context);
+}

modules/sum.js

@@ -0,0 +1,25 @@
+import isArrayLike from './_isArrayLike.js';
+import values from './values.js';
+import cb from './_cb.js';
+import each from './each.js';
+
+// Return the sum of elements (or element-based computation).
+export default function sum(obj, iteratee, context) {
+    if (!iteratee && _.isEmpty(obj)){
+        return 0;
+    }
+  var result = 0;
+  if (iteratee == null || typeof iteratee == 'number' && typeof obj[0] != 'object' && obj != null) {
+    obj = isArrayLike(obj) ? obj : values(obj);
+    for (var i = 0, length = obj.length; i < length; i++) {
+      result += obj[i];
+    }
+  } else {
+    iteratee = cb(iteratee, context);
+    each(obj, function(v, index, list) {
+      computed = iteratee(v, index, list);
+      result += computed;
+    });
+  }
+  return result;
+}

modules/variance.js

@@ -0,0 +1,34 @@
+import isArrayLike from './_isArrayLike.js';
+import values from './values.js';
+import cb from './_cb.js';
+import each from './each.js';
+import mean from './avg.js'
+
+// Return the variance element (or element-based computation).
+export default function variance(obj, iteratee, context) {
+  if (!iteratee && _.isEmpty(obj)){
+      return 0;
+  }
+  var result = 0;
+  if (iteratee == null || typeof iteratee == 'number' && typeof obj[0] != 'object' && obj != null) {
+    obj = isArrayLike(obj) ? obj : values(obj);
+    var avg = mean(obj);
+    var squareDiffs = obj.map(function(value){
+        return (value - avg) * (value - avg);;
+    });
+    result = mean(squareDiffs);
+  } else {
+    var tmpObj;
+    iteratee = cb(iteratee, context);
+    each(obj, function(v, index, list) {
+      computed = iteratee(v, index, list);
+      tmpObj.push(iteratee ? computed : v);
+    });
+    var avg = mean(tmpObj);
+    var squareDiffs = tmpObj.map(function(value){
+        return (value - avg) * (value - avg);;
+    });
+    result = mean(squareDiffs);
+  }
+  return result;
+}