NoneSafe-EX

A None-safe wrapper for Python containers, preventing KeyError, IndexError, and AttributeError when accessing missing or None values.

** Warn: NoneLike is not None. Please do not use NoneLike is None to check if a value is None. == None or is NoneLike is recommended.**

Features

• NoneSafeDict: None-safe dictionary - returns NoneLike instead of raising KeyError
• NoneSafeList: None-safe list - returns NoneLike for out-of-bounds access
• NoneLike: Sentinel object that supports arbitrary chained access without raising exceptions

Installation

pip install nonesafe_ex

Usage

NoneSafeDict

from nonesafe_ex import NoneSafeDict

data = NoneSafeDict({"name": "Alice", "info": {"age": 25}})

# Access existing key
print(data["name"])  # "Alice"

# Access non-existing key - returns NoneLike instead of KeyError
print(data["non_existing"])  # None
print(bool(data["non_existing"]))  # False

# Nested access with automatic wrapping
print(data["info"]["age"])  # 25
print(data["info"]["non_existing"])  # None (NoneLike)

# Safe chained access
result = data["info"]["address"]["city"]
print(result)  # None

NoneSafeList

from nonesafe import NoneSafeList

items = NoneSafeList([1, 2, {"value": 3}])

# Access existing index
print(items[0])  # 1

# Out-of-bounds access - returns NoneLike instead of IndexError
print(items[100])  # None
print(items[-100])  # None

# Nested access with automatic wrapping
print(items[2]["value"])  # 3
print(items[2]["non_existing"])  # None

# Iteration with automatic wrapping
for item in items:
    print(item)

NoneLike

from nonesafe import NoneLike

# Supports arbitrary chained access
result = NoneLike.foo.bar.baz()["key"]
print(result)  # None
print(bool(result))  # False

# Safe for any operation
print(NoneLike + 1)  # None
print(NoneLike * 2)  # None
print(len(NoneLike))  # 0

API

NoneSafeDict

• __getitem__(key) - Returns wrapped value or NoneLike if key not found
• get(key, default=None) - Returns wrapped value or wrapped default
• values() - Returns wrapped values view
• items() - Returns items view with wrapped values
• pop(key, default=None) - Removes and returns wrapped value
• copy() - Returns new NoneSafeDict

NoneSafeList

• __getitem__(index) - Returns wrapped value or NoneLike if out of bounds
• pop(index=-1) - Removes and returns wrapped value
• copy() - Returns new NoneSafeList
• first(default=None) - Returns first item or wrapped default
• last(default=None) - Returns last item or wrapped default

NoneLike

• Supports chained attribute access: NoneLike.attr.subattr
• Supports chained item access: NoneLike["key"]["subkey"]
• Supports function calls: NoneLike.method()
• Boolean value is False
• String representation is "None"

License

MIT