Contents
In this post, we will go over how to sort an array in JavaScript. We will discuss the different methods for sorting an array as well as the time and space complexity for each method.
Checkout this video:
Introduction
JavaScript arrays are sparse arrays, which means that not all of the elements in an array may contain data. Because of this, it’s important to know how to sort an array in JavaScript so that you can manipulate the data in it.
There are a few different ways to sort an array in JavaScript, but the most common way is to use the Array.sort() method. This method sorts the elements of an array in place and doesn’t return a new array.
What is an Array?
An array is a collection of items stored at contiguous memory locations. The idea is to store multiple items of the same type together. This makes it easier to calculate the position of each item by simply adding an offset to a base value, i.e., the memory location of the first item in the array ( generically referred to as the “base address” ).
Each item in an array is called an element, and each element is accessed by its numerical index. As such, arrays are sometimes referred to as zero-based indexing.
The following declaration creates an array named courses that stores five elements:
var courses = new Array(“HTML”, “CSS”, “JavaScript”, “jQuery”, “Bootstrap”);
What is Sorting?
In computer science, sorting is the process of organizing data so that it can be easily accessed and analyzed. There are a variety of different sorting algorithms that can be used to sort data, and each has its own advantages and disadvantages. The most common sorting algorithm used in JavaScript is the quicksort algorithm, which is an efficient way to sort small sets of data.
Why Sort an Array?
Sorting arrays in JavaScript is a complex problem with many different solutions. The reason for this is because there are so many different ways to sort an array. Some sorting algorithms are very simple, while others are very complex. The most common way to sort an array is by using the Array.sort() method.
The Array.sort() method accepts a callback function as its first argument. The callback function is used to compare two values in the array. The callback function must return a positive number if the first value is greater than the second value, a negative number if the first value is less than the second value, or 0 if the two values are equal.
In order to use the Array.sort() method, you need to understand how it works. In this article, we will take a closer look at how the Array.sort() method works and how you can use it to sort an array in JavaScript.
How to Sort an Array in JavaScript?
JavaScript arrays are used to store multiple values in a single variable. You can sort an array in JavaScript using the sort() method. The sort() method will sort the elements of an array in place and return the sorted array. The default sort order is alphabetical, but you can pass a compare function to the sort() method to customize the sort order.
Comparison Functions
When you call the sort() method on an array, JavaScript will sort the element in alphabetically ascending order. However, if you want to sort the element in a certain way, you can pass a comparison function to the sort() method.
A comparison function is a callback function that compares two values and returns a negative value if the first value is less than the second value, a zero if both values are equal, or a positive value if the first value is greater than the second value.
The comparison function has the following syntax:
function(a, b) {
// return value goes here
}
For example, let’s say you have an array of numbers and you want to sort them in ascending order. However, you want all of the even numbers to come before all of the odd numbers. In this case, you can pass a comparison function to the sort() method that checks whether or not a number is even or odd. If it’s even, it will come before all odd numbers; if it’s odd, it will come after all even numbers.
The following code sorts an array of numbers in ascending order and uses a comparison function to put all of the even numbers first:
var arr = [1,2,3,4,5];
arr.sort(function(a, b){return a-b}) // [1, 2, 3 ,4 ,5 ]
Sorting Strings
You can use the sort() method of Array, which takes a callback function, which takes as parameters 2 items in the Array being sorted.
The following code sorts an array of strings in alphabetical order:
let fruits = [“cherry”, “apple”, “blueberry”];
fruits.sort();
// Result: [“apple”, “blueberry”, “cherry”]
Sorting Numbers
In JavaScript, there are multiple ways to sort an array of numbers.
One way is to use the built-in sort() method. The sort method takes an optional function as a parameter, which can be used to control how the array is sorted.
If no function is passed as a parameter, the array elements are sorted according to converted them to strings and comparing them in Unicode code point order.
var numbers = [4, 2, 5, 1, 3];
numbers.sort();
//=> [1, 2, 3, 4, 5]
To sort the array in descending order, you can pass in a function that reversing the result of the comparison between two element values.
var numbers = [4, 2, 5, 1, 3];
numbers.sort(function(a, b) {
return b – a;
});
//=> [5, 4 ,3 ,2 ,1]
Sorting Dates
Sorting dates can be a little tricky, but luckily, there are a few different ways to do it. If you have an array of dates that you need to sort, you can use the Array.sort() method. This method will take an array of dates and sort them in ascending order. If you need to sort the dates in descending order, you can use the Array().reverse() method.
The Array.sort() method will take an array of dates and sort them in ascending order. To sort the dates in descending order, you can use the Array().reverse() method.
Conclusion
Though there are many ways to sort an array in JavaScript, the most common way is to use the Array.sort() method. This method will take an array as input and output a new array with the values sorted in ascending or descending order. To sort in ascending order, simply pass in a comparator function that returns a positive number if the first value is greater than the second, a negative number if the first value is less than the second, or 0 if they are equal. To sort in descending order, simply reverse the Comparator function so that it returns a negative number if the first value is greater than the second, etc.
