Hash tables allow mapping keys to values by using a hashing function. Here the hashing function actually computes the index of the key mapped to a specific value. But I just can't get my head around why we even use hash tables it in the first place? Why do you need a hash table? Are maps/dictionaries not good enough? Why not declare a dictionary ({'key1': 'value1'} in Python) and use it in the places where a hash table is required? I read a lot about it and still don't get it. Can you help me understand this?
why do you need a hashtable, is the map/dictionary not good
This is like asking why you need an automotive engine, isn't a car good enough? An engine is how a car works; you just don't see the engine when you are driving the car. But if you are learning to become an automotive engineer, then you should learn how engines work and how to design, build and maintain them.
Likewise, a hash table is how a dictionary works, you just don't see the hash table if you are writing code that uses a dictionary. But if you are learning to become a computer scientist, then you should learn how hash tables and other data structures work, and how to design, build and maintain them.