Completed ARRAYS-4-DAYZ lab

part01/BasicArrays.js

@@ -4,31 +4,44 @@ class BasicArrays{
      * @return the first element in the array
      */
     getFirstElement(stringArray) {
-        return null;
+           return stringArray[0];
     }
 
     /**
      * @param stringArray an array of String objects
      * @return the second element in the array
      */
     getSecondElement(stringArray) {
-        return null;
+        return stringArray[1];
     }
 
     /**
      * @param stringArray an array of String objects
      * @return stringArray with the elements in reverse order
      */
     reverse(stringArray) {
-        return null;
+        let newArray = [];
+         for(let i=stringArray.length - 1; i>=0; i--){
+            newArray.push(stringArray[i]);
+        }
+        return newArray;
     }
 
     /**
      * @param stringArray an array of String objects
      * @return String made up of the first character in each element of stringArray
      */
    getFirstLetterOfEachElement(stringArray) {
-        return null;
+        let newArray = [];
+        let firstElement = [];
+
+       for (let i=0; i<=stringArray.length-1; i++){
+           newArray += stringArray[i][0];
+
+       }
+       firstElement.push(newArray);
+
+        return (firstElement.join(""));
     }   
 }
 

part01/BasicArrays.test.js

@@ -17,7 +17,7 @@ test("getSecondTest", () => {
 
     let basicArrays = new BasicArrays();
     let inputArray = ["The", "quick", "brown"];
-    let expected = "The";
+    let expected = "quick";
 
     let actual = basicArrays.getSecondElement(inputArray);
 
@@ -38,7 +38,7 @@ test("reverseArrayTest", () => {
 test("firstLetterTest", () => {
 
     let basicArrays = new BasicArrays();
-    let inputArray = ["The", "quick", "brown"];
+    let inputArray = ["The", "quick", "brown", "fox"];
     let expected = "Tqbf";
 
     let actual = basicArrays.getFirstLetterOfEachElement(inputArray);

part02/Craze4Arrays.js

@@ -1,13 +1,31 @@
 class Craze4Arrays{
 
+    getNumberOfOccurrences(objectArray, objectToEvaluate) {
+        let numOfOccurrences = 0;
+
+        for (let i = 0; i<objectArray.length; ++i ){
+            if (objectArray[i] == objectToEvaluate)
+            numOfOccurrences++;
+        }
+        return numOfOccurrences;
+    }
+
+
+
     /** 
         @param objectArray    an array of any type of Object
         @param objectToRemove a value to be removed from the `objectArray`
         @return an array with identical content excluding the specified `objectToRemove`
         Given an array of objects, name `objectArray`, and an object `objectToRemove`, return an array of objects with identical contents excluding `objectToRemove`
     */
     removeValue(objectArray, objectToRemove) {
-        return null;
+        for (let i=0; i<objectArray.length; i++){
+        if (objectArray[i] === objectToRemove){
+            objectArray.splice(i, 1);
+            i--;
+        }
+       } 
+        return  objectArray;
     }
 
     /**
@@ -16,16 +34,38 @@ class Craze4Arrays{
      * given an array of objects, named `objectArray` return the most frequently occuring object in the array
      */
     getMostCommon(objectArray) {
-        return null;
-    }
+        let m = 0;
+        let mf = 1;
+        let mode;
+        for (let i=0; i<objectArray.length; i++){
+            for (let j = i; j<objectArray.length; j++){
+                if (objectArray[i] == objectArray[j])
+                m++;
+                if (mf<m){
+                    mf=m;
+                }
+            }
+            mode = mf;
+            m=0; 
+        }
+
+        return mode;
+        }
+
+
 
     /**
      * @param objectArray an array of any type of Object
      * @return the least frequently occurring object in the array
      * given an array of objects, named `objectArray` return the least frequently occuring object in the array
      */
-   getLeastCommon(objectArray) {
-        return null;
+   getLeastCommon(objectArray){
+       let leastCommon = objectArray.sort((a,b) =>
+            objectArray.filter(v => v===b).length
+          - objectArray.filter(v => v===a).length
+          ).pop();
+
+        return leastCommon;
     }
 
     /**
@@ -34,8 +74,9 @@ class Craze4Arrays{
      * @return an array containing all elements in `objectArray` and `objectArrayToAdd`
      * given two arrays `objectArray` and `objectArrayToAdd`, return an array containing all elements in `objectArray` and `objectArrayToAdd`
      */
-    pmergeArrays(objectArray, objectArrayToAdd) {
-        return null;
+    mergeArrays(objectArray, objectArrayToAdd) {
+        let mergedArray = objectArray.concat(objectArrayToAdd);
+        return mergedArray;
     }
 
 }

part02/Craze4Arrays.test.js

@@ -26,6 +26,14 @@ test("removeValueTest1", () => {
     expect(actual).toEqual(expected);
 });
 
+test("getMostCommonTest", () => {
+    let craze4Arrays = new Craze4Arrays();
+    let expected = 4;
+    let inputArray = [1,1,2,3,3,3,4,4,4,4];
+    let actual = craze4Arrays.getMostCommon(inputArray);
+    expect(actual).toEqual(expected);
+});
+
 test("getLeastCommonTest", () => {
     let craze4Arrays = new Craze4Arrays();
     let expected = 2;