1. Syntax

Python

• General Characteristics:

  • Indentation-Based: Uses indentation to define code blocks.

  • Whitespace Significant: Proper indentation is crucial.

  • Readable and Clean: Emphasizes readability.

• Example:

def greet(name):
    if name:
        print(f"Hello, {name}!")
    else:
        print("Hello, World!")

greet("Alice")

JavaScript

• General Characteristics:

  • Brace-Based: Uses curly braces {} to define code blocks.

  • Semicolons Optional: Though not required, semicolons can be used to terminate statements.

  • Flexible Syntax: More flexibility with code structure.

• Example:

function greet(name) {
  if (name) {
    console.log(`Hello, ${name}!`);
  } else {
    console.log('Hello, World!');
  }
}

greet('Alice');

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2. Memory Management and How It Works Under the Hood

Python

• Automatic Memory Management:

  • Garbage Collection: Uses reference counting and a cyclic garbage collector to manage memory.

  • Memory Allocation: Handled by Python’s memory manager, abstracting complexity from the developer.

• Under the Hood:

  • Reference Counting: Keeps track of the number of references to each object.

  • Cycle Detection: Identifies and collects objects that reference each other, preventing memory leaks. JavaScript

• Automatic Memory Management:

  • Garbage Collection: Primarily uses mark-and-sweep algorithms.

  • Memory Allocation: Managed by the JavaScript engine (e.g., V8), abstracting complexity from the developer.

• Under the Hood:

  • Mark-and-Sweep: Periodically scans memory to identify and collect unused objects.

  • Generational Collection: Optimizes garbage collection by categorizing objects based on their lifespan.

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3. Types of Data with Examples and Syntax

Python

• Primitive Types:
  • Integer: int

age = 30

• Float: float

pi = 3.14159

• String: str

name = "Alice"

• Boolean: bool

is_active = True

• Composite Types:
  • List: Ordered, mutable collection

fruits = ["apple", "banana", "cherry"]

• Tuple: Ordered, immutable collection

coordinates = (10, 20)

• Dictionary: Key-value pairs

person = {"name": "Alice", "age": 30}

• Set: Unordered, unique elements

unique_numbers = {1, 2, 3}

JavaScript

• Primitive Types:
  • Number: Represents both integers and floats

let age = 30;
let pi = 3.14159;

• String: string

let name = 'Alice';

• Boolean: boolean

let isActive = true;

• Undefined: undefined

let data;

• Null: null

let empty = null;

• Symbol: Unique and immutable

let sym = Symbol('unique');

• Composite Types:
  • Object: Key-value pairs

let person = { name: 'Alice', age: 30 };

• Array: Ordered collection

let fruits = ['apple', 'banana', 'cherry'];

• Function: First-class objects

function greet(name) {
  return `Hello, ${name}!`;
}

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4. Syntax of Basic Constructs with Examples and Syntax

Python If Statement

x = 10
if x > 5:
    print("x is greater than 5")
elif x == 5:
    print("x is equal to 5")
else:
    print("x is less than 5")

Loops

• For Loop:

for i in range(5):
    print(i)

• While Loop:

count = 0
while count < 5:
    print(count)
    count += 1

Functions

def add(a, b):
    return a + b

result = add(3, 5)
print(result)  # Output: 8

Lists

fruits = ["apple", "banana", "cherry"]
print(fruits[0])  # Output: apple

Objects (Dictionaries)

person = {"name": "Alice", "age": 30}
print(person["name"])  # Output: Alice

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JavaScript If Statement

let x = 10;
if (x > 5) {
  console.log('x is greater than 5');
} else if (x === 5) {
  console.log('x is equal to 5');
} else {
  console.log('x is less than 5');
}

Loops

• For Loop:

for (let i = 0; i < 5; i++) {
  console.log(i);
}

• While Loop:

let count = 0;
while (count < 5) {
  console.log(count);
  count++;
}

Functions

function add(a, b) {
  return a + b;
}

let result = add(3, 5);
console.log(result); // Output: 8

Arrays

let fruits = ['apple', 'banana', 'cherry'];
console.log(fruits[0]); // Output: apple

Objects

let person = { name: 'Alice', age: 30 };
console.log(person.name); // Output: Alice

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5. Float Numbers and How They're Saved in Memory with Examples and Syntax

Python

• Float Representation:

  • Double Precision: Python’s float type uses double-precision (64-bit) IEEE 754 format.

  • Storage: Consists of sign bit, exponent, and mantissa.

• Example:

pi = 3.141592653589793
print(pi)  # Output: 3.141592653589793

• Memory Storage:

  • Internally stored as binary fractions.

  • Limited precision can lead to rounding errors.

print(0.1 + 0.2)  # Output: 0.30000000000000004

JavaScript

• Float Representation:

  • Double Precision: JavaScript’s Number type also uses double-precision (64-bit) IEEE 754 format.

  • Storage: Similar structure with sign bit, exponent, and mantissa.

• Example:

let pi = 3.141592653589793;
console.log(pi); // Output: 3.141592653589793

• Memory Storage:

  • Internally stored as binary fractions.

  • Limited precision can lead to rounding errors.

console.log(0.1 + 0.2); // Output: 0.30000000000000004

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6. Types of Functions with Examples and Syntax

Python

• Function Types:
  • Standard Functions:

def greet(name):
    return f"Hello, {name}!"

print(greet("Alice"))  # Output: Hello, Alice!

• Lambda Functions (Anonymous Functions):

add = lambda a, b: a + b
print(add(3, 5))  # Output: 8

• Higher-Order Functions:

def apply_function(func, value):
    return func(value)

def square(x):
    return x * x

print(apply_function(square, 4))  # Output: 16

• Generator Functions:

def count_up_to(max):
    count = 1
    while count <= max:
        yield count
        count += 1

counter = count_up_to(5)
for num in counter:
    print(num)
# Output: 1 2 3 4 5

JavaScript

• Function Types:
  • Function Declarations:

function greet(name) {
  return `Hello, ${name}!`;
}

console.log(greet('Alice')); // Output: Hello, Alice!

• Function Expressions:

const add = function (a, b) {
  return a + b;
};

console.log(add(3, 5)); // Output: 8

• Arrow Functions:

const multiply = (a, b) => a * b;
console.log(multiply(3, 5)); // Output: 15

• Higher-Order Functions:

function applyFunction(func, value) {
  return func(value);
}

function square(x) {
  return x * x;
}

console.log(applyFunction(square, 4)); // Output: 16

• Generator Functions:

function* countUpTo(max) {
  let count = 1;
  while (count <= max) {
    yield count;
    count++;
  }
}

const counter = countUpTo(5);
for (let num of counter) {
  console.log(num);
}
// Output: 1 2 3 4 5

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7. OOP and Inheritance with Examples and Syntax

Python

• Class Definition and Inheritance:

class Animal:
    def __init__(self, name):
        self.name = name

    def speak(self):
        pass

class Dog(Animal):
    def speak(self):
        return f"{self.name} says Woof!"

class Cat(Animal):
    def speak(self):
        return f"{self.name} says Meow!"

dog = Dog("Buddy")
cat = Cat("Whiskers")

print(dog.speak())  # Output: Buddy says Woof!
print(cat.speak())  # Output: Whiskers says Meow!

• Key Points:

  • Inheritance: Use parentheses to inherit from a parent class.

  • Method Overriding: Subclasses can override methods of the parent class.

  • super() Function: To call methods from the parent class.

• Class Definition and Inheritance (ES6 Syntax):

class Animal {
  constructor(name) {
    this.name = name;
  }

  speak() {
    // To be overridden by subclasses
  }
}

class Dog extends Animal {
  speak() {
    return `${this.name} says Woof!`;
  }
}

class Cat extends Animal {
  speak() {
    return `${this.name} says Meow!`;
  }
}

const dog = new Dog('Buddy');
const cat = new Cat('Whiskers');

console.log(dog.speak()); // Output: Buddy says Woof!
console.log(cat.speak()); // Output: Whiskers says Meow!

• Key Points:

  • Inheritance: Use extends keyword to inherit from a parent class.

  • Method Overriding: Subclasses can override methods of the parent class.

  • super() Function: To call the constructor or methods from the parent class.

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Summary Table

Topic	Python	JavaScript
Syntax	Indentation-based, readableExample:python def greet(name): print(f"Hello, {name}!")	Brace-based, flexibleExample:javascript function greet(name) { console.log(Hello, ${name}!); }
Memory Management	Automatic with reference counting and garbage collector	Automatic with mark-and-sweep and generational collection
Data Types	int, float, str, bool, list, tuple, dict, setExample:python age = 30	Number, String, Boolean, Undefined, Null, Symbol, Object, ArrayExample:javascript let age = 30;
Basic Constructs	if, for, while, def, list, dictExample:python if x > 5: print(x)	if, for, while, function, array, objectExample:javascript if (x > 5) { console.log(x); }
Floats	Double-precision (float)Example:python pi = 3.14	Double-precision (Number)Example:javascript let pi = 3.14;
Functions	Standard, lambda, higher-order, generatorsExample:python def add(a, b): return a + b	Function declarations, expressions, arrow functions, higher-order, generatorsExample:javascript function add(a, b) { return a + b; }
OOP & Inheritance	class, inheritance using parenthesesExample:python class Dog(Animal): def speak(self): return "Woof!"	class, extends keywordExample:javascript class Dog extends Animal { speak() { return "Woof!"; } }

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This comparison covers the fundamental aspects of Python and JavaScript across various programming concepts. Make sure to practice writing and understanding code in both languages to solidify your understanding for the exam. Good luck!