arrays and loops

js/advanced.js

@@ -1,8 +1,184 @@
 //Level2
 
-//arrays and array manipulations
+/* Arrays
+    It is ordered list of values. It can keep any number of values inside. And also
+    any type of values - numbers, strings, objects.
+    Example:
+    var animals = ['cat', 'dog', 'horse];
+    var randomThings = [2, 'book', 'today is Saturday', 10];
+    var numbers = [1, 2, 8, 19];
+ */
+
+//TODO: create your own array named favouriteFood and write in couple of things you like.
+
+var favouriteFood = ['jk', 'jksf', 'hjl', 'dfsl'];
+
+/* Array length
+    We can easily check how many items we have in our array with property '.length'
+    Example:
+    var randomThings = [2, 'book', 'today is Saturday', 10];
+    console.log(randomThings.length); //we will get 4
+ */
+
+//TODO: check up on how many values you have in your array favouriteFood and console.log it
+
+console.log(favouriteFood.length);
+
+/* Arrays usage
+    So, it is comfortable to keep all this values in one place, but what if we want to use
+    only 1 item from the array, we can get them out using 'bracket notation'.
+    As all counting in programming starts with 0, the first element in the array will have
+    position 0 etc
+    Example:
+    var randomThings = [2, 'book', 'today is Saturday', 10];
+    var firstItem = randomThings[0];
+    var secondItem = randomThings[1]; and so on
+ */
+
+//TODO: get 3d element from your array favouriteFood and console.log it
+
+console.log(favouriteFood[2]);
+
+/* Changing values in arrays
+    We also can replace values inside of the arrays by assigning specific item from
+    the array to a new value.
+    Example:
+    var animals = ['cat', 'dog', 'horse];
+    //let's replace 'dog' with 'fish'
+    animals[1] = 'fish';
+    //now our animals array will be ['cat', 'fish', 'horse]
+ */
+
+//TODO: take your array favouriteFood and replace first value with anything else.
+//console.log whole array to check
+
+favouriteFood[0] = 'melon';
+console.log(favouriteFood);
+
+/* Adding values to array
+    If you want to add new value to array you can use property of array named '.push'.
+    It will add value to the end of the array
+    Example:
+    var animals = ['cat', 'dog', 'horse];
+    animals.push('rabbit');
+ */
+
+//TODO: let's extend your list of favouriteFood and add one more value in it.
+//console.log list of your food o check
+
+favouriteFood.push('cherries');
+console.log(favouriteFood);
+
+
+/* Loops
+    People always have been lazy and it was moving progress forward. We don't like repeat
+    same boring actions again and again, so we are looking for the way how to improve it.
+    Programming is the same - for example, if I want to print 'JavaScript is awesome!' 10
+    times what are my options? Of course, I can print 10 lines of code repeating same
+    phrase over and over again, but I also can tell computer to do it instead of me.
+    To do it we have loops.
+    Each loop should have 3 main things:
+    - starting point
+    - condition (finishing point)
+    - counter (a step)
+    If you miss one of them you can get into infinite loop!!!
+ */
+
+
+/* While loops
+  'While' loop will do the action over and over again untill
+  some condition will be met.
+  For example:
+  var number = 0;   //starting point
+  while (number < 10) {      //10 is a condition/finishing point
+    console.log('JavaScript is awesome!');
+    number = number + 1;          // + 1 is a counter/size of the step
+  }
+ */
+
+//TODO: Using 'while loop' tell your computer to print you numbers from 10 to 1
+
+var num = 10;
+
+while(num > 0) {
+  console.log(num);
+  num = num - 1;
+}
+
+/* For loops
+    'For loop' is very similar to 'while loop', but you declare a counter in the statement.
+    For example:
+    for(var i = 0; i <= 5; i++){  //(starting point, condition, step)
+      console.log('Purr');
+    }
+    PS: i++ is a short from 'i = i + 1'
+ */
+
+//TODO: now, let's print every 3d number from 3 to 22 using 'for loop'
+
+for(var i = 3; i <= 22; i + 3){
+  console.log(i);
+}
+
+
+/* Iterating through arrays
+    Now, when we know about loops I want to use each value from my animal
+    list and say that I love all of those animals, how shall I do it?
+    We can use 'for loop' to iterate through our array and get each value from it.
+    Example:
+    var animals = ['cats', 'dogs', 'horses];
+    for(var i = 0; i < animals.length; i++){
+      console.log('I love ' + animals[i]);
+    }
+ */
+
+//TODO: try it out with your list of favouriteFood that you created before.
+
+
+
+
+
+
+
+
+
+
+
+/* Loops and Logic
+    Now, when we know about if/else statements and loops let's combine them together
+    and make something more interesting. Let's count from 10 to 0 and print all the
+    numbers, but when we get to the middle(5) print ''WooHoo, we are in the middle'.
+    Example:
+    for(var i = 10; i > 0; i--){
+      if(i == 5){
+        console.log('WooHoo, we are in the middle');
+      } else {
+        console.log(i);
+      }
+    }
+ */
+
+//TODO: Time came for a classic exercise - 'FizzBuzz'. Count from 1 to 50 and print
+// numbers out. If number multiple of 3 print 'Fizz', if multiple of 5 - 'Buzz', if
+// it is multiple of 3 and 5 - 'FizzBuzz'.
+//PS: you can use arithmetic operator modulo (%) - it is remainder when dividing.
+//10 % 3 = 1 - so in 10 we have 3*3 + 1
+//16 % 4 = 0 - as in 16 we have 4*4
+//19 % 4 = 3 - as in 19 we have 4*4 + 3 etc
+
+
+
+
+
+
+
+
+
+
+
+
+
 
-//loops - while loop, for loop, infinite loop
 
 
 //events - clicks etc

js/dom-manipulation.js

@@ -1,19 +1,15 @@
 //getting and adding elements to the page (pre-written code with explanations)
 
-window.onload = function () {
-
-    var getElement = function (classname) {
-        return document.querySelector(classname);
-    };
-
-    var getValue = function (classname) {
-        var el = getElement(classname);
-        return el.innerHTML;
-    };
+var getElement = function (classname) {
+  return document.querySelector(classname);
+};
 
-    var displayValue = function (classname, value) {
-        var el = getElement(classname);
-        return el.innerHTML = value;
-    };
+var getValue = function (classname) {
+  var el = getElement(classname);
+  return el.innerHTML;
+};
 
+var displayValue = function (classname, value) {
+  var el = getElement(classname);
+  return el.innerHTML = value;
 };