FlatDict

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FlatDict is a Python module for interacting with nested dicts as a single level dict with delimited keys. FlatDict supports Python 2.7+ and 3.4+.

Jump to Installation, Example Use, Class Documentation, or license.

For example:

foo = {'foo': {'bar': 'baz', 'qux': 'corge'}}

is represented as:

{'foo:bar': 'baz',
 'foo:qux': 'corge'}

And can still be accessed as:

foo['foo']['bar']

and

foo['foo:bar']

Additionally, lists and tuples are also converted into dicts using enumerate().

For example:

d = {'list': ['a', 'b', 'c',]}

Will be flattened as follows:

flat = {'list:0': 'a', 'list:1': 'b', 'list:2': 'c'}

Installation

$ pip install flatdict

Example Use

import flatdict

values = {'foo': {'bar': {'baz': 0,
                          'qux': 1,
                          'corge': 2},
                  'grault': {'baz': 3,
                             'qux': 4,
                             'corge': 5}},
          'garply': {'foo': 0, 'bar': 1, 'baz': 2, 'qux': {'corge': 3}}}

flat = flatdict.FlatDict(values)

print(flat['foo:bar:baz'])

flat['test:value:key'] = 10

del flat['test']

for key in flat:
    print(key)

for values in flat.itervalues():
    print(value)

print(repr(flat.as_dict()))

print(flat == flat.as_dict())

Class Documentation

FlatDict is a dict object that allows for single level, delimited key/value pair mapping of nested dictionaries.

class flatdict.FlatDict(value=None, delimiter=':')[source]

FlatDict is a dictionary object that allows for single level, delimited key/value pair mapping of nested dictionaries. The default delimiter value is : but can be changed in the constructor or by calling FlatDict.set_delimiter().

as_dict()[source]

Return the FlatDict as a dict

Return type:dict
clear()[source]

Remove all items from the flat dictionary.

copy()[source]

Return a shallow copy of the flat dictionary.

Return type:flatdict.FlatDict
fromkeys(S[, v]) → New dict with keys from S and values equal to v.

v defaults to None.

get(key, d=None)[source]

Return the value for key if key is in the flat dictionary, else default. If default is not given, it defaults to None, so that this method never raises KeyError.

Parameters:
  • key (mixed) – The key to get
  • d (mixed) – The default value
Return type:

mixed
has_key(k) → True if D has a key k, else False
items()[source]

Return a copy of the flat dictionary’s list of (key, value) pairs.

Note

CPython implementation detail: Keys and values are listed in an arbitrary order which is non-random, varies across Python implementations, and depends on the flat dictionary’s history of insertions and deletions.

Return type:list
iteritems()[source]

Return an iterator over the flat dictionary’s (key, value) pairs. See the note for flatdict.FlatDict.items().

Using iteritems() while adding or deleting entries in the flat dictionary may raise RuntimeError or fail to iterate over all entries.

Return type:Iterator
Raises:RuntimeError
iterkeys()[source]

Iterate over the flat dictionary’s keys. See the note for flatdict.FlatDict.items().

Using iterkeys() while adding or deleting entries in the flat dictionary may raise RuntimeError or fail to iterate over all entries.

Return type:Iterator
Raises:RuntimeError
itervalues()[source]

Return an iterator over the flat dictionary’s values. See the note flatdict.FlatDict.items().

Using itervalues() while adding or deleting entries in the flat dictionary may raise a RuntimeError or fail to iterate over all entries.

Return type:Iterator
Raises:RuntimeError
keys()[source]

Return a copy of the flat dictionary’s list of keys. See the note for flatdict.FlatDict.items().

Return type:list
pop(key, default=None)[source]

If key is in the flat dictionary, remove it and return its value, else return default. If default is not given and key is not in the dictionary, KeyError is raised.

Parameters:
  • key (mixed) – The key name
  • default (mixed) – The default value
Return type:

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

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

set_delimiter(delimiter)[source]

Override the default or passed in delimiter with a new value. If the requested delimiter already exists in a key, a ValueError will be raised.

Parameters:delimiter (str) – The delimiter to use
Raises:ValueError
setdefault(key, default)[source]

If key is in the flat dictionary, return its value. If not, insert key with a value of default and return default. default defaults to None.

Parameters:
  • key (mixed) – The key name
  • default (mixed) – The default value
Return type:

mixed
update(other=None, **kwargs)[source]

Update the flat dictionary with the key/value pairs from other, overwriting existing keys.

update() accepts either another flat dictionary object or an iterable of key/value pairs (as tuples or other iterables of length two). If keyword arguments are specified, the flat dictionary is then updated with those key/value pairs: d.update(red=1, blue=2).

Parameters:other (iterable) – Iterable of key, value pairs
Return type:None
values()[source]

Return a copy of the flat dictionary’s list of values. See the note for flatdict.FlatDict.items().

Return type:list
viewitems() → a set-like object providing a view on D's items
viewkeys() → a set-like object providing a view on D's keys
viewvalues() → an object providing a view on D's values
class flatdict.FlatterDict(value=None, delimiter=':')[source]

Like FlatDict but also coerces lists and sets to child-dict instances with the offset as the key. Alternative to the implementation added in v1.2 of FlatDict.

as_dict()[source]

Return the FlatDict as a dict, or if the class was originally populated as a list or tuple, return it as such.

Return type:dict
clear()

Remove all items from the flat dictionary.

copy()

Return a shallow copy of the flat dictionary.

Return type:flatdict.FlatDict
fromkeys(S[, v]) → New dict with keys from S and values equal to v.

v defaults to None.

get(key, d=None)

Return the value for key if key is in the flat dictionary, else default. If default is not given, it defaults to None, so that this method never raises KeyError.

Parameters:
  • key (mixed) – The key to get
  • d (mixed) – The default value
Return type:

mixed
has_key(k) → True if D has a key k, else False
items()

Return a copy of the flat dictionary’s list of (key, value) pairs.

Note

CPython implementation detail: Keys and values are listed in an arbitrary order which is non-random, varies across Python implementations, and depends on the flat dictionary’s history of insertions and deletions.

Return type:list
iteritems()

Return an iterator over the flat dictionary’s (key, value) pairs. See the note for flatdict.FlatDict.items().

Using iteritems() while adding or deleting entries in the flat dictionary may raise RuntimeError or fail to iterate over all entries.

Return type:Iterator
Raises:RuntimeError
iterkeys()

Iterate over the flat dictionary’s keys. See the note for flatdict.FlatDict.items().

Using iterkeys() while adding or deleting entries in the flat dictionary may raise RuntimeError or fail to iterate over all entries.

Return type:Iterator
Raises:RuntimeError
itervalues()

Return an iterator over the flat dictionary’s values. See the note flatdict.FlatDict.items().

Using itervalues() while adding or deleting entries in the flat dictionary may raise a RuntimeError or fail to iterate over all entries.

Return type:Iterator
Raises:RuntimeError
keys()

Return a copy of the flat dictionary’s list of keys. See the note for flatdict.FlatDict.items().

Return type:list
pop(key, default=None)

If key is in the flat dictionary, remove it and return its value, else return default. If default is not given and key is not in the dictionary, KeyError is raised.

Parameters:
  • key (mixed) – The key name
  • default (mixed) – The default value
Return type:

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

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

set_delimiter(delimiter)

Override the default or passed in delimiter with a new value. If the requested delimiter already exists in a key, a ValueError will be raised.

Parameters:delimiter (str) – The delimiter to use
Raises:ValueError
setdefault(key, default)

If key is in the flat dictionary, return its value. If not, insert key with a value of default and return default. default defaults to None.

Parameters:
  • key (mixed) – The key name
  • default (mixed) – The default value
Return type:

mixed
update(other=None, **kwargs)

Update the flat dictionary with the key/value pairs from other, overwriting existing keys.

update() accepts either another flat dictionary object or an iterable of key/value pairs (as tuples or other iterables of length two). If keyword arguments are specified, the flat dictionary is then updated with those key/value pairs: d.update(red=1, blue=2).

Parameters:other (iterable) – Iterable of key, value pairs
Return type:None
values()

Return a copy of the flat dictionary’s list of values. See the note for flatdict.FlatDict.items().

Return type:list
viewitems() → a set-like object providing a view on D's items
viewkeys() → a set-like object providing a view on D's keys
viewvalues() → an object providing a view on D's values