datahold 0.2.27

datahold

Overview

Wrap common mutable datastructures for inheritance with modification.

Content

BaseList

To understand the class BaseList here the beginning of its code:

class BaseList:

    data: list

    @functools.wraps(list.__add__)
    def __add__(self, *args, **kwargs):
        data = self.data
        ans = data.__add__(*args, **kwargs)
        self.data = data
        return ans

The following methods are defined this way: __add__, __contains__, __delitem__, __eq__, __format__, __ge__, __getitem__, __gt__, __hash__, __iadd__, __imul__, __iter__, __le__, __len__, __lt__, __mul__, __repr__, __reversed__, __rmul__, __setitem__, __str__, append, clear, copy, count, extend, index, insert, pop, remove, reverse, sort

The only function present in list and absent in BaseList is __class_getitem__

We can use BaseList as parent for a list-like class. It is recommended to implement is the subclass: - a property named data with getter and setter wrapping a private variable (for example named _data) - the __init__ magic method This allows the creatation of a list-like class with modified behaviour with only minimal effort. To enhance perpormance we can overwrite some of the methods.

OkayList

This class inherits from BaseList and implements some common sense overwrites for further inheritance. For example:

• the comparison operations are overwritten:

• __eq__ returns True iff types are equal and data is equal

• __ne__ negates __eq__

• __ge__ returns type(self)(other).__le__(self)

• __gt__ returns True iff __eq__ returns False and __ge__ returns True

• __lt__ returns True iff __eq__ returns False and __le__ returns True

• __le__ returns self.data.__le__(type(self)(other).data)

• modify __eq__ or __le__ as needed to change the behaviour of the other comparison methods

• __hash__ raises now a more fitting exception

• __iadd__ uses now extend

• __init__ allows now to set data immediately

• see the code for all overwrites

BaseDict

Just like BaseList but for dict… The following methods are implemented: __contains__, __delitem__, __eq__, __format__, __ge__, __getitem__, __gt__, __hash__, __ior__, __iter__, __le__, __len__, __lt__, __or__, __repr__, __reversed__, __ror__, __setitem__, __str__, clear, copy, get, items, keys, pop, popitem, setdefault, update, values`` The classmethods __class_getitem__ and fromkeys are not implemented.

BaseSet

Just like BaseSet but for set… The following methods are implemented: __and__, __contains__, __eq__, __format__, __ge__, __gt__, __hash__, __iand__, __ior__, __isub__, __iter__, __ixor__, __le__, __len__, __lt__, __or__, __rand__, __repr__, __ror__, __rsub__, __rxor__, __str__, __sub__, __xor__, add, clear, copy, difference, difference_update, discard, intersection, intersection_update, isdisjoint, issubset, issuperset, pop, remove, symmetric_difference, symmetric_difference_update, union, update The classmethod __class_getitem__ is not implemented.

Installation

To install datahold, you can use pip. Open your terminal and run:

pip install datahold

License

This project is licensed under the MIT License.

Links

• Download

• Source

Credits

• Author: Johannes

• Email: [e-mail]

Thank you for using datahold!