The Immutable Package

This package presents access to an Immutable object which adheres to the Python Mapping and Sequence APIs. That is, function calls like .items(), .count(), .index(), .keys(), etc will work.

It allows you to instantiate via a tuple or via kwargs. It simplifies the case where you know ahead of time what the values of an Immutable should be and you just need to instantiate it once.

It also allows for nested objects and Immutable object comparisons. It should be noted that you can change these objects by accessing the .__dict__ attr, accessing the self.__dict__['_ordered_dict'] object. The idea is that there are enough red flags at that point to steer anyone away.

Install

pip install immutable

Details

Immutable

This is the main class in the package. You can use it like this:

from immutable import Immutable

# This results in an unordered object.
imm = Immutable(zero=0, one=1, two=2, three=3)

# This results in an ordered object.
imm = Immutable(('zero', 0), ('one', 1), ('two', 2), ('three', 3))

# You can access like a Sequence with indices.
two = imm[2]

# You can also access via the '.' operator.
three = imm.three

# Iterating works as you'd expect.
for value in imm.values():
    print value

# Trying to set an attribute via the '.' operator will fail.
imm.two = 3  # ImmutableError

# Trying to set an attribute via the `[]` operator will fail.
imm[2] = 3  # ImmutableError

# Instantiating with a mutable will fail (which is desirable).
imm = Immutable(mutable=[1, 2, 3])  # Immutable Error

# You can nest Immutable objects too (which gets around using dicts).
imm = Immutable(
    key = 'something',
    sub_imm = Immutable(
        sub_key = (1, 2, 3)
    )
)