arrays

03 - Javascript arrays/01.js

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+// Sort an array of strings alphabetically
+
+// Write a function that takes an array of strings as argument
+// It should return the array with its values sorted alphabetically
+
+function myFunction(arr) {
+  return arr.sort();
+}
+
+console.log(myFunction(["b", "c", "d", "a"])); // ['a', 'b', 'c', 'd']
+console.log(myFunction(["z", "c", "d", "a", "y", "a", "w"])); // ['a', 'a', 'c', 'd', 'w', 'y', 'z']

03 - Javascript arrays/02.js

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+// Sort an array of numbers in descending order
+
+// Write a function that takes an array of numbers as argument
+// It should return an array with the numbers sorted in descending order
+
+function myFunction(arr) {
+  return arr.sort((a, b) => b - a);
+}
+
+console.log(myFunction([1, 3, 2])); // [3,2,1]
+console.log(myFunction([4, 2, 3, 1])); // [4,3,2,1]

03 - Javascript arrays/03.js

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+// Return last n array elements
+
+// Write a function that takes an array and a number (n) as arguments
+// It should return the last n array elements
+// If the array has less than n elements, return all
+
+function myFunction(arr, n) {
+  return arr.splice(-n);
+
+  //   AUTHOR'S
+  // return arr.slice(-n);
+}
+
+console.log(myFunction([1, 2, 3, 4, 5], 2)); // [4, 5]
+console.log(myFunction([1, 2, 3], 6)); // [1, 2, 3]
+console.log(myFunction([1, 2, 3, 4, 5, 6, 7, 8], 3)); // [6, 7, 8]

03 - Javascript arrays/04.js

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+// Sum up all array elements with values greater than
+
+// Write a function that takes an array and a number, say num, as arguments
+// Sum up all array elements with a value greater than num
+// Return the sum
+
+function myFunction(arr, num) {
+  return arr.filter((el) => el > num).reduce((acc, cur) => acc + cur);
+
+  // AUTHOR'S:
+  //   return arr.reduce((sum, cur) => {
+  //     if (cur > num) return sum + cur;
+  //     return sum;
+  //   }, 0);
+}
+
+console.log(myFunction([1, 2, 3, 4, 5, 6, 7], 2)); // 25
+console.log(myFunction([-10, -11, -3, 1, -4], -3)); // 1
+console.log(myFunction([78, 99, 100, 101, 401], 99)); // 602

03 - Javascript arrays/05.js

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+// Return the average of an array of numbers
+
+// Write a function that takes an array of numbers as argument
+// It should return the average of the numbers
+
+function myFunction(arr) {
+  return arr.reduce((acc, cur) => acc + cur, 0) / arr.length;
+}
+
+console.log(myFunction([10, 100, 40])); // 50
+console.log(myFunction([10, 100, 1000])); // 370
+console.log(myFunction([-50, 0, 50, 200])); // 50

03 - Javascript arrays/06.js

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+// Check if all array elements are equal
+
+// Write a function that takes an array as argument
+// It should return true if all elements in the array are equal
+// It should return false otherwise
+
+function myFunction(arr) {
+  return arr.every((el) => el === arr[0]);
+
+  // AUTHOR'S:
+  //   return new Set(arr).size === 1;
+}
+
+console.log(myFunction([true, true, true, true])); // true
+console.log(myFunction(["test", "test", "test"])); // true
+console.log(myFunction([1, 1, 1, 2])); // false
+console.log(myFunction(["10", 10, 10, 10])); // false

03 - Javascript arrays/07.js

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+// Remove a specific array element
+
+// Write a function that takes an array and a value as argument
+// The function should clean the array from all occurrences of the given value and return the the cleaned version
+
+function myFunction(arr, val) {
+  return arr.filter((el) => el !== val);
+}
+
+console.log(myFunction([1, 2, 3], 2)); // [1, 3]
+console.log(myFunction([1, 2, "2"], "2")); // [1, 2]
+console.log(myFunction([false, "2", 1], false)); // ['2', 1]
+console.log(myFunction([1, 2, "2", 1], 1)); // [2, '2']

03 - Javascript arrays/08.js

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+// Create a range of numbers
+
+// Write a function that takes two numbers, say min and max, as arguments
+// Return an array of numbers in the range min to max
+
+function myFunction(min, max) {
+  const arr = [];
+  for (let i = min; i <= max; i++) arr.push(i);
+  return arr;
+}
+
+console.log(myFunction(2, 10)); // [2, 3, 4, 5, 6, 7, 8, 9, 10]
+console.log(myFunction(1, 3)); // [1, 2, 3]
+console.log(myFunction(-5, 5)); // [-5, -4, -3, -2, -1, 0,  1,  2,  3,  4, 5]
+console.log(myFunction(2, 7)); // [2, 3, 4, 5, 6, 7]

03 - Javascript arrays/09.js

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+// Return the longest string from an array of strings
+
+// Write a function that takes an array of strings as argument
+// It should return the longest string
+
+// function myFunction(arr) {
+//   return arr.reduce((acc, cur) => {
+//     if (cur.length > acc.length) return (acc = cur);
+//     return acc;
+//   }, "");
+// }
+
+// function myFunction(arr) {
+//   let acc = "";
+
+//   arr.forEach((el) => {
+//     if (el.length > acc.length) acc = el;
+//   });
+
+//   return acc;
+// }
+
+// AUTHOR'S:
+function myFunction(arr) {
+  return arr.reduce((acc, cur) => (acc.length <= cur.length ? cur : acc));
+}
+
+console.log(myFunction(["help", "me"])); // 'help'
+console.log(myFunction(["I", "need", "candy"])); // 'candy'

03 - Javascript arrays/10.js

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+// Merge an arbitrary number of arrays
+
+// Write a function that takes arguments an arbitrary number of arrays
+// It should return an array containing the values of all arrays
+
+function myFunction(...arr) {
+  return arr.flat();
+}
+
+console.log(myFunction([1, 2, 3], [4, 5, 6])); // [1, 2, 3, 4, 5, 6]
+console.log(myFunction(["a", "b", "c"], [4, 5, 6])); // ['a', 'b', 'c', 4, 5, 6]
+console.log(myFunction([true, true], [1, 2], ["a", "b"])); // [true, true, 1, 2, 'a', 'b']

03 - Javascript arrays/11.js

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+function myFunction(a, b) {
+  //   return Array.from(new Set([...a, ...b])).sort((a, b) => a - b);
+
+  //   const arr = [];
+  //   a.concat(b).forEach((el) => {
+  //     if (!arr.includes(el)) arr.push(el);
+  //   });
+  //   return arr.sort((a, b) => a - b);
+
+  // AUTHOR'S:
+  return [...new Set([...a, ...b])].sort((a, b) => a - b);
+}
+
+console.log(myFunction([1, 2, 3], [3, 4, 5])); // [1, 2, 3, 4, 5]
+console.log(myFunction([-10, 22, 333, 42], [-11, 5, 22, 41, 42])); // [-11, -10, 5, 22, 41,  42, 333]

README.md

@@ -1,7 +1,8 @@
 # JSchallenger
 
-Learn Javascript online by solving coding exercises.
-[JSchallenger](https://www.jschallenger.com)
+[JSchallenger](https://www.jschallenger.com) Learn Javascript online by solving coding exercises.
+
+![alt text](README/logo.png)
 
 - What: JavaScript challenges from JSchallenger.com. It includes my own code in case I got it right as well as challenge's author code.
 - Why: Just in case someone is starting, as I am currently, to learn JS and wants to practice.
@@ -30,17 +31,17 @@ Big thanks to the author of JSchallenger.com. It's not easy to find such good ex
 
 ## Javascript arrays
 
-- [Sort an array of strings alphabetically]()
-- [Sort an array of numbers in descending order]()
-- [Return last n array elements]()
-- [Return the average of an array of numbers]()
-- [Sum up all array elements with values greater than]()
-- [Check if all array elements are equal]()
-- [Remove a specific array element]()
-- [Create a range of numbers]()
-- [Return the longest string from an array of strings]()
-- [Merge an arbitrary number of arrays]()
-- [Merge two arrays with duplicate values]()
+- [Sort an array of strings alphabetically](03%20-%20Javascript%20arrays/01.js)
+- [Sort an array of numbers in descending order](03%20-%20Javascript%20arrays/02.js)
+- [Return last n array elements](03%20-%20Javascript%20arrays/03.js)
+- [Return the average of an array of numbers](03%20-%20Javascript%20arrays/04.js)
+- [Sum up all array elements with values greater than](03%20-%20Javascript%20arrays/05.js)
+- [Check if all array elements are equal](03%20-%20Javascript%20arrays/06.js)
+- [Remove a specific array element](03%20-%20Javascript%20arrays/07.js)
+- [Create a range of numbers](03%20-%20Javascript%20arrays/08.js)
+- [Return the longest string from an array of strings](03%20-%20Javascript%20arrays/09.js)
+- [Merge an arbitrary number of arrays](03%20-%20Javascript%20arrays/10.js)
+- [Merge two arrays with duplicate values](03%20-%20Javascript%20arrays/11.js)
 
 ## Javascript dates