What data structure underlies the dict in Python? How are collisions resolved?

In Python, dict is implemented based on a hash table with open addressing and the use of open addressing with probing.

Main points:

• Keys are hashed to obtain an index in the array.
• When a collision occurs (when two keys have the same index), a probing method is used, where the next free cell is searched according to a specific algorithm.
• In Python 3.6+, an ordered dictionary implementation is used, which preserves the insertion order.

Collision resolution examples include linear probing or double hashing, but in CPython, a variable step probing algorithm is used to reduce clustering.

This ensures efficient access, insertion, and deletion of elements.