Jkb java scriptintro2

js-data-types-lab/lab.js

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+
+// Part 1: strings
+
+
+let fullName = "James Barclay";
+
+console.log("Length:", fullName.length);
+console.log("Uppercase:", fullName.toUpperCase());
+console.log("Includes Barclay:", fullName.includes("Barclay"));
+console.log("First Name:", fullName.slice(0, 5));
+
+// mini challenge
+function greet(name) {
+  return "HELLO, " + name.toUpperCase() + "!";
+}
+
+console.log(greet("James Barclay"));
+
+// Check for Understanding:
+// 1. .length basically returns number of characters in a string
+// 2. .includes() just returns true or false
+// 3. .slice() just extracts part of a string
+
+
+// Part 2: numbers
+
+
+let num1 = 10;
+let num2 = 3;
+
+console.log("Add:", num1 + num2);
+console.log("Subtract:", num1 - num2);
+console.log("Multiply:", num1 * num2);
+console.log("Divide:", num1 / num2);
+console.log("Remainder:", num1 % num2);
+
+console.log("Rounded:", Math.round(3.7));
+console.log("Random 1-10:", Math.floor(Math.random() * 10) + 1);
+
+// mini challenge
+function evenOrOdd(num) {
+  if (num % 2 === 0) {
+    return "Even";
+  } else {
+    return "Odd";
+  }
+}
+
+console.log(evenOrOdd(7));
+
+// Check for Understanding:
+// 1. % gives remainder
+// 2. Math.random() returns a number between 0 and 1
+// 3. Math.floor() rounds down to the nearest
+
+
+
+// Part 3: arrays
+
+let students = ["A", "B", "C", "D"];
+
+// print all students
+for (let i = 0; i < students.length; i++) {
+  console.log(students[i]);
+}
+
+// add new student
+students.push("E");
+
+// remove last student
+students.pop();
+
+// total number
+console.log("Total Students:", students.length);
+
+
+function sumArray(arr) {
+  let sum = 0;
+  for (let i = 0; i < arr.length; i++) {
+    sum += arr[i];
+  }
+  return sum;
+}
+
+console.log("Sum:", sumArray([1, 2, 3, 4]));
+
+// Check for Understanding:
+// 1. Use index like arr[0]
+// 2. .push() adds to end
+// 3. Loops help go through each item
+
+
+
+// Part 4: objects
+
+
+let car = {
+  brand: "Ford",
+  model: "Taurus",
+  year: 2000
+};
+
+// print properties
+console.log(car.brand);
+console.log(car.model);
+console.log(car.year);
+
+// update year
+car.year = 2000;
+
+// add color
+car.color = "Silver";
+
+// looping through the object
+for (let key in car) {
+  console.log(key, car[key]);
+}
+
+
+function describePerson(person) {
+  return person.name + " is " + person.age + " years old";
+}
+
+console.log(describePerson({ name: "James Barclay", age: 34 }));
+
+//check understanding
+// 1. Key-value is basically property: value
+// 2. Use dot/bracket notation
+// 3. Use objects for structured data
+
+
+
+
+let student = {
+  name: "James Barclay",
+  scores: [80, 90, 75, 100]
+};
+
+function calculateAverage(scores) {
+  let total = 0;
+
+  for (let i = 0; i < scores.length; i++) {
+    total += scores[i];
+  }
+
+  return total / scores.length;
+}
+
+function getGrade(avg) {
+  if (avg >= 90) return "A";
+  else if (avg >= 80) return "B";
+  else if (avg >= 70) return "C";
+  else if (avg >= 60) return "D";
+  else return "F";
+}
+
+let average = calculateAverage(student.scores);
+let grade = getGrade(average);
+
+console.log("Name:", student.name);
+console.log("Average:", average);
+console.log("Grade:", grade);
+
+
+
+// Reflection
+
+// 1. Easiest: Strings because methods are simple and clear
+// 2. Most confusing: Objects loops (for...in)
+// 3. Arrays store lists, objects store labeled data
+// 4. Arrays = lists (scores), Objects = structured data (user profiles)