BUILT-IN DATA STRUCTURES
Through the lens of Big O
Now that we've covered BIG O...
Let's spend a couple minutes analyzing the things we do all the time in JS: working with Arrays, Objects, and built-in methods.
We spend a lot of this course talking about data structures.
Let's start by discussing the ones we get for free
OBJECTIVES
- Understand how objects and arrays work, through the lens of Big O
- Explain why adding elements to the beginning of an array is costly
- Compare and contrast the runtime for arrays and objects, as well as built-in methods
OBJECTS
let instructor = {
firstName: "Kelly",
isInstructor: true,
favoriteNumbers: [1,2,3,4]
}Unordered, key value pairs!
When to use objects
- When you don't need order
- When you need fast access / insertion and removal
Big O of Objects
Insertion - O(1)
Removal - O(1)
Searching - O(N)
Access - O(1)
When you don't need any ordering, objects are an excellent choice!
Big O of Object Methods
Object.keys - O(N)
Object.values - O(N)
Object.entries - O(N)
hasOwnProperty - O(1)
ARRAYS
let names = ["Michael", "Melissa", "Andrea"];
let values = [true, {}, [], 2, "awesome"];Ordered lists!
WHEN TO USE ARRAYS
- When you need order
- When you need fast access / insertion and removal (sort of....)
Big O of Arrays
Insertion - It depends....
Removal - It depends....
Searching - O(N)
Access - O(1)
Let's see what we mean by that!
Big O of Array Operations
- push - O(1)
- pop - O(1)
- shift - O(N)
- unshift - O(N)
- concat - O(N)
- slice - O(N)
- splice - O(N)
- sort - O(N * log N)
- forEach/map/filter/reduce/etc. - O(N)
You don't need to know all this...
😵
Limitations of Arrays
Inserting at the beginning is not as easy as we might think! There are more efficient data structures for that!
Big O Of Arrays and Objects
By colt_steele
Big O Of Arrays and Objects
- 21,439
