Math.round(); Math.max(); Math.min(); Math.abs(); Math.pow(); Math.sqrt(); Math.sign(); Math.trunc(); teach me these function with examples
JavaScript Math Functions Tutorial
Let me walk you through these essential JavaScript Math functions with practical examples.
Math.round()
The Math.round() function rounds a number to the nearest integer.
// Basic rounding
console.log(Math.round(4.3)); // 4
console.log(Math.round(4.5)); // 5
console.log(Math.round(4.7)); // 5
// Negative numbers
console.log(Math.round(-4.3)); // -4
console.log(Math.round(-4.5)); // -4 (rounds toward positive infinity)
console.log(Math.round(-4.7)); // -5Math.max()
The Math.max() function returns the largest of the provided numbers.
// Finding maximum value
console.log(Math.max(5, 10, 15)); // 15
console.log(Math.max(-5, -10, -15)); // -5
// With arrays (using spread operator)
const numbers = [5, 10, 15, 20];
console.log(Math.max(...numbers)); // 20
// If no arguments are provided
console.log(Math.max()); // -InfinityMath.min()
The Math.min() function returns the smallest of the provided numbers.
// Finding minimum value
console.log(Math.min(5, 10, 15)); // 5
console.log(Math.min(-5, -10, -15)); // -15
// With arrays (using spread operator)
const numbers = [5, 10, 15, 20];
console.log(Math.min(...numbers)); // 5
// If no arguments are provided
console.log(Math.min()); // InfinityMath.abs()
The Math.abs() function returns the absolute value of a number.
// Absolute values
console.log(Math.abs(5)); // 5
console.log(Math.abs(-5)); // 5
console.log(Math.abs(-3.14)); // 3.14
// Useful for calculating differences
const point1 = 10;
const point2 = 25;
const distance = Math.abs(point1 - point2);
console.log(distance); // 15Math.pow()
The Math.pow() function returns the base to the exponent power.
// Basic powers
console.log(Math.pow(2, 3)); // 8 (2³)
console.log(Math.pow(5, 2)); // 25 (5²)
console.log(Math.pow(4, 0.5)); // 2 (square root of 4)
// Negative exponents
console.log(Math.pow(2, -2)); // 0.25 (1/2²)
// Note: Modern JavaScript also offers the ** operator
console.log(2 ** 3); // 8 (same as Math.pow(2, 3))Math.sqrt()
The Math.sqrt() function returns the square root of a number.
// Square roots
console.log(Math.sqrt(9)); // 3
console.log(Math.sqrt(2)); // 1.4142135623730951 (√2)
console.log(Math.sqrt(0)); // 0
// Negative numbers return NaN
console.log(Math.sqrt(-4)); // NaNMath.sign()
The Math.sign() function returns the sign of a number, indicating whether it's positive, negative, or zero.
// Sign of numbers
console.log(Math.sign(10)); // 1 (positive)
console.log(Math.sign(-10)); // -1 (negative)
console.log(Math.sign(0)); // 0
console.log(Math.sign(-0)); // -0
// Non-number values
console.log(Math.sign('10')); // 1 (converts to number first)
console.log(Math.sign('hello')); // NaNMath.trunc()
The Math.trunc() function returns the integer part of a number by removing any fractional digits.
// Truncating numbers
console.log(Math.trunc(13.37)); // 13
console.log(Math.trunc(42.84)); // 42
console.log(Math.trunc(0.123)); // 0
// Negative numbers
console.log(Math.trunc(-13.37)); // -13
// Difference from Math.floor() with negative numbers
console.log(Math.trunc(-4.9)); // -4
console.log(Math.floor(-4.9)); // -5Key Differences Between These Functions
- Math.round() vs Math.trunc():
Math.round()rounds to the nearest integer, whileMath.trunc()simply removes the decimal part. - Math.trunc() vs Math.floor(): For positive numbers, they behave the same, but for negative numbers,
Math.floor(-4.9)returns -5, whileMath.trunc(-4.9)returns -4. - Math.pow() vs Math.sqrt():
Math.pow(x, 0.5)is equivalent toMath.sqrt(x)- both calculate the square root. - Math.abs() vs Math.sign():
Math.abs()returns the magnitude of a number, whileMath.sign()only tells you if it's positive (1), negative (-1), or zero (0).
Practical Applications
- Math.round(): Useful for rounding prices, percentages, or any decimal values to whole numbers.
- Math.max()/Math.min(): Great for finding highest/lowest scores, temperatures, or values in datasets.
- Math.abs(): Perfect for calculating distances or differences without caring about direction.
- Math.pow(): Used in calculations involving area, volume, compound interest, or exponential growth.
- Math.sqrt(): Essential for distance calculations (Pythagorean theorem), standard deviations, and more.
- Math.sign(): Helpful for determining direction or trend (positive/negative).
- Math.trunc(): Useful when you need just the integer part without rounding.
I've created an interactive demo above where you can try out each of these functions with your own inputs!
Array() filter(); explain me this in chat with examples
Understanding JavaScript's Array.filter() Method
The Array.filter() method creates a new array containing elements that pass a test implemented by the provided function. It's one of the most useful array methods for extracting specific elements from an array based on certain conditions.
Basic Syntax
const newArray = array.filter(callback(element[, index[, array]])[, thisArg])Where:
callback: Function to test each element of the arrayelement: The current element being processedindex(optional): The index of the current elementarray(optional): The array filter() was called uponthisArg(optional): Value to use asthiswhen executing callback
How filter() Works
- It iterates through each element in the array
- It runs the callback function on each element
- If the callback returns
true, the element is included in the new array - If the callback returns
false, the element is excluded - It returns a new array without modifying the original
Basic Examples
Filtering Numbers
Let's filter out numbers less than 10:
const numbers = [5, 12, 8, 130, 44];
const filtered = numbers.filter(num => num >= 10);
console.log(filtered); // Output: [12, 130, 44]Filtering Strings
Filter strings with more than 5 characters:
const fruits = ["apple", "banana", "grape", "watermelon", "kiwi"];
const longFruits = fruits.filter(fruit => fruit.length > 5);
console.log(longFruits); // Output: ["banana", "watermelon"]More Complex Examples
Filtering Objects
Filter objects based on a property:
const products = [
{ name: "Laptop", price: 1200, inStock: true },
{ name: "Phone", price: 800, inStock: true },
{ name: "Tablet", price: 650, inStock: false },
{ name: "Headphones", price: 300, inStock: true }
];
// Get only in-stock products
const availableProducts = products.filter(product => product.inStock);
console.log(availableProducts);
// Output: [
// { name: "Laptop", price: 1200, inStock: true },
// { name: "Phone", price: 800, inStock: true },
// { name: "Headphones", price: 300, inStock: true }
// ]
// Get products with price less than 1000
const affordableProducts = products.filter(product => product.price < 1000);
console.log(affordableProducts);
// Output: [
// { name: "Phone", price: 800, inStock: true },
// { name: "Tablet", price: 650, inStock: false },
// { name: "Headphones", price: 300, inStock: true }
// ]Using Index Parameter
Filter elements based on their position:
const numbers = [10, 20, 30, 40, 50];
const evenIndexedNumbers = numbers.filter((num, index) => index % 2 === 0);
console.log(evenIndexedNumbers); // Output: [10, 30, 50]Filtering Out Falsy Values
Remove all falsy values from an array:
const mixedArray = [0, 1, false, 2, '', 3, null, undefined, NaN];
const truthyValues = mixedArray.filter(Boolean);
console.log(truthyValues); // Output: [1, 2, 3]Filtering Unique Values
Create an array with unique values (before Set was widely available):
const numbers = [1, 2, 2, 3, 4, 4, 5];
const unique = numbers.filter((value, index, self) => {
return self.indexOf(value) === index;
});
console.log(unique); // Output: [1, 2, 3, 4, 5]Search Functionality
Implementing a simple search filter:
const users = [
{ name: "John Smith", age: 28 },
{ name: "Jane Doe", age: 32 },
{ name: "John Doe", age: 40 },
{ name: "Mary Smith", age: 25 }
];
function searchUsers(query) {
return users.filter(user =>
user.name.toLowerCase().includes(query.toLowerCase())
);
}
console.log(searchUsers("john"));
// Output: [
// { name: "John Smith", age: 28 },
// { name: "John Doe", age: 40 }
// ]
console.log(searchUsers("smith"));
// Output: [
// { name: "John Smith", age: 28 },
// { name: "Mary Smith", age: 25 }
// ]Chaining with Other Array Methods
You can chain filter() with other array methods like map() or reduce():
const numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
// Filter even numbers and double them
const doubledEvens = numbers
.filter(num => num % 2 === 0)
.map(num => num * 2);
console.log(doubledEvens); // Output: [4, 8, 12, 16, 20]
// Filter numbers greater than 5 and calculate their sum
const sumOfLargeNumbers = numbers
.filter(num => num > 5)
.reduce((sum, num) => sum + num, 0);
console.log(sumOfLargeNumbers); // Output: 40 (6+7+8+9+10)Important Notes
filter()always returns a new array and doesn't modify the original array 1- If no elements pass the test, an empty array is returned
filter()does not execute the callback function for empty array elements- Unlike
forEach(), you can't break out of afilter()operation
Practical Use Cases
- Filtering data based on user input
- Removing unwanted elements (like null values)
- Implementing search functionality
- Data validation
- Creating subsets of data for different views
The filter() method is a powerful tool for working with arrays in JavaScript, allowing you to extract exactly the data you need based on specific conditions.
how the memory alocation is there if in heap then is in date varaible there will address of that heap memory
