Different meanings of brackets in Python

Question

I am curious, what do the 3 different brackets mean in Python programming? Not sure if I\'m correct about this, but please correct me if I\'m wrong:

[] - # No         


        

Answer 1

In addition to Maltysen's answer and for future readers: you can define the [] and () operators in a class, by defining the class methods:

• __call__(self[, args...]) for ()
• __getitem__(self, key) for []

An example is numpy.mgrid[...]. In this way you can define it on your custom-made objects for any purpose you like.

Answer 2

() parentheses are used for order of operations, or order of evaluation, and are referred to as tuples. [] brackets are used for lists. List contents can be changed, unlike tuple content. {} are used to define a dictionary in a "list" called a literal.

Answer 3

• []: Used to define mutable data types - lists, list comprehensions and for indexing/lookup/slicing.
• (): Define tuples, order of operations, generator expressions, function calls and other syntax.
• {}: The two hash table types - dictionaries and sets.