Filtering Arrays with the filter() Method
This chapter delves into the intricacies of the filter()
method, elucidating its syntax, applications, and how it facilitates the creation of refined arrays.
filter()
The filter()
method selects elements that meet a particular condition. Let's decipher the syntax:
js9123array.filter((element, index, array) => {// Callback body});
Here's what we need to know about the filter() method:
It does not alter the original array;
It iterates over the original array element by element;
It returns a new array;
Elements are added to the new array if they satisfy the callback condition;
If the callback returns true, the element is included; otherwise, it is omitted.
Examples
The true prowess of the filter()
method becomes apparent when applied to diverse scenarios. Let's delve into some illustrative examples:
Example 1: Filtering Odd Numbers
In this example, the filter()
method creates an array (oddNumbers
) comprising only odd numbers from the original array.
123456const numbers = [15, 22, 37, 41, 58, 67, 72]; const oddNumbers = numbers.filter((number) => { return number % 2 !== 0; }); console.log(oddNumbers); // Output: 15, 37, 41, 67
Example 2: Filtering Products by Price Range
Here, the filter()
method is utilized to extract products with prices below $500, creating a new array (affordableProducts
).
js9912345678910const products = [{ name: "Keyboard", price: 220 },{ name: "Smartphone", price: 800 },{ name: "Tablet", price: 500 },{ name: "Headphones", price: 120 },{ name: "Camera", price: 1500 },];const affordableProducts = products.filter((product) => product.price < 500);console.log(affordableProducts); // Output: [ { name: "Keyboard", price: 220 }, { name: "Headphones", price: 120 } ]
1. What does the filter()
method do?
2. What is a key characteristic of the filter()
method?
3. In the example below, what should be the condition so that the numbersGreaterThan20
array would contain numbers greater than 20?
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