dantro.utils.ordereddict module

Definition of an OrderedDict-subclass that maintains the order key values rather than the insertion order. It can be specialized to use a specific comparison function for ordering keys.

class dantro.utils.ordereddict.KeyOrderedDict(*args, key: Callable = None, **kwds)

Bases: dict

This dict maintains the order of keys not by their insertion but by their value. It is a re-implementation of collections.OrderedDict, because subclassing that class is really difficult.

Ordering is maintained by adjusting those methods of OrderedDict that take care of building and maintaining the doubly-linked list that provides the ordering. See OrderedDict for details, e.g. the weak-referencing.

In effect, this relates only to __setitem__; all other methods rely on this to add elements to the mapping.

For comparison, the key callable given at initialisation can be used to perform a operation on keys, the result of which is used in comparison. If this is not given, the DEFAULT_KEY_COMPARATOR class variable is used; note that this needs to be a binary function, where the first argument is equivalent to self and the second is the actual key to perform the unary operation on.

DEFAULT_KEY_COMPARATOR(k)

__init__(*args, key: Callable = None, **kwds)

Initialize a KeyOrderedDict, which maintains key ordering. If no custom ordering function is given, orders by simple “smaller than” comparison.

Apart from that, the interface is the same as for regular dictionaries.

Parameters

• *args – a single sequence of (key, value) pairs to insert

• key (Callable, optional) – The callable used to

• **kwds – Passed on to update method

Raises

TypeError – on len(args) > 1

_key_comp_lt(k1, k2) → bool

The key comparator. Returns true for k1 < k2.

Before comparison, the unary self._key method is invoked on both keys.

Parameters

• k1 – lhs of comparison

• k2 – rhs of comparison

Returns

k1 < k2

Return type

bool

__setitem__(key, value, *, dict_setitem=<slot wrapper '__setitem__' of 'dict' objects>, proxy=<built-in function proxy>, Link=<class 'collections._Link'>)

Set the item with the provided key to the given value, maintaining the ordering specified by NEW_KEY_GT_NEXT_KEY

If the key is not available, this takes care of finding the right place to insert the new link in the doubly-linked list.

insert(key, value, *, hint_after=None, hint_before=None)

Inserts a (key, value) pair using hint information to speed up key search.

__delitem__(key, dict_delitem=<slot wrapper '__delitem__' of 'dict' objects>)

kod.__delitem__(y) <==> del kod[y]

Deleting an existing item uses self.__map to find the link which gets removed by updating the links in the predecessor and successor nodes.

__iter__() <==> iter(kod)

Traverse the linked list in order.

__reversed__() <==> reversed(kod)

Traverse the linked list in reverse order.

clear()

Remove all items

__sizeof__()

Get the size of this object

update([E, ]**F) → None. Update D from mapping/iterable E and F.

If E present and has a .keys() method, does: for k in E: D[k] = E[k] If E present and lacks .keys() method, does: for (k, v) in E: D[k] = v In either case, this is followed by: for k, v in F.items(): D[k] = v

keys() → a set-like object providing a view on D's keys

items() → a set-like object providing a view on D's items

values() → an object providing a view on D's values

pop(k[, d]) → v, remove specified key and return the

corresponding value. If key is not found, default is returned if given, otherwise KeyError is raised.

setdefault(k[, d]) → kod.get(k,d), also set kod[k]=d if k not

in kod

__reduce__()

Return state information for pickling

copy() → a shallow copy of kod, maintaining the key comparator

classmethod fromkeys(S[, v]) → New key-ordered dictionary with keys from S.

If not specified, the value defaults to None.

__eq__(other)

kod.__eq__(y) <==> kod==y. Comparison to another KeyOrderedDict or OrderedDict is order-sensitive while comparison to a regular mapping is order-insensitive.

_KeyOrderedDict__marker = <object object>

_KeyOrderedDict__update(**kwds)

D.update([E, ]**F) -> None. Update D from mapping/iterable E and F. If E present and has a .keys() method, does: for k in E: D[k] = E[k] If E present and lacks .keys() method, does: for (k, v) in E: D[k] = v In either case, this is followed by: for k, v in F.items(): D[k] = v

get()

Return the value for key if key is in the dictionary, else default.

popitem() → (k, v), remove and return some (key, value) pair as a

2-tuple; but raise KeyError if D is empty.

class dantro.utils.ordereddict.IntOrderedDict(*args, key: Callable = None, **kwds)

Bases: dantro.utils.ordereddict.KeyOrderedDict

A KeyOrderedDict specialization that assumes keys to be castable to integer and using the comparison of the resulting integer values for maintaining the order

DEFAULT_KEY_COMPARATOR(k)

_KeyOrderedDict__marker = <object object>

_KeyOrderedDict__update(**kwds)

D.update([E, ]**F) -> None. Update D from mapping/iterable E and F. If E present and has a .keys() method, does: for k in E: D[k] = E[k] If E present and lacks .keys() method, does: for (k, v) in E: D[k] = v In either case, this is followed by: for k, v in F.items(): D[k] = v

__delitem__(key, dict_delitem=<slot wrapper '__delitem__' of 'dict' objects>)

kod.__delitem__(y) <==> del kod[y]

Deleting an existing item uses self.__map to find the link which gets removed by updating the links in the predecessor and successor nodes.

__eq__(other)

kod.__eq__(y) <==> kod==y. Comparison to another KeyOrderedDict or OrderedDict is order-sensitive while comparison to a regular mapping is order-insensitive.

__init__(*args, key: Callable = None, **kwds)

Initialize a KeyOrderedDict, which maintains key ordering. If no custom ordering function is given, orders by simple “smaller than” comparison.

Apart from that, the interface is the same as for regular dictionaries.

Parameters

• *args – a single sequence of (key, value) pairs to insert

• key (Callable, optional) – The callable used to

• **kwds – Passed on to update method

Raises

TypeError – on len(args) > 1

__iter__() <==> iter(kod)

Traverse the linked list in order.

__reduce__()

Return state information for pickling

__reversed__() <==> reversed(kod)

Traverse the linked list in reverse order.

__setitem__(key, value, *, dict_setitem=<slot wrapper '__setitem__' of 'dict' objects>, proxy=<built-in function proxy>, Link=<class 'collections._Link'>)

Set the item with the provided key to the given value, maintaining the ordering specified by NEW_KEY_GT_NEXT_KEY

If the key is not available, this takes care of finding the right place to insert the new link in the doubly-linked list.

__sizeof__()

Get the size of this object

_key_comp_lt(k1, k2) → bool

The key comparator. Returns true for k1 < k2.

Before comparison, the unary self._key method is invoked on both keys.

Parameters

• k1 – lhs of comparison

• k2 – rhs of comparison

Returns

k1 < k2

Return type

bool

clear()

Remove all items

copy() → a shallow copy of kod, maintaining the key comparator

classmethod fromkeys(S[, v]) → New key-ordered dictionary with keys from S.

If not specified, the value defaults to None.

get()

Return the value for key if key is in the dictionary, else default.

insert(key, value, *, hint_after=None, hint_before=None)

Inserts a (key, value) pair using hint information to speed up key search.

items() → a set-like object providing a view on D's items

keys() → a set-like object providing a view on D's keys

pop(k[, d]) → v, remove specified key and return the

corresponding value. If key is not found, default is returned if given, otherwise KeyError is raised.

popitem() → (k, v), remove and return some (key, value) pair as a

2-tuple; but raise KeyError if D is empty.

setdefault(k[, d]) → kod.get(k,d), also set kod[k]=d if k not

in kod

update([E, ]**F) → None. Update D from mapping/iterable E and F.

If E present and has a .keys() method, does: for k in E: D[k] = E[k] If E present and lacks .keys() method, does: for (k, v) in E: D[k] = v In either case, this is followed by: for k, v in F.items(): D[k] = v

values() → an object providing a view on D's values