python

• d.copy()
  

  Return a shallow copy of the dictionary.

• d.fromkeys(seq[, value])
  

  Create a new dictionary with keys from seq and all of values set to value.
  fromkeys() is a class method that return a new dictionary. value defaults to None.

• d.clear()
  

  Remove all items from the dictionary.

• d.pop(key[, default])
  

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

• d.popitem()
  

  Remove and return a arbitrary (key, value) pair from dictionary.
  If the dictionary is empty, calling popitem() raises a KeyError.

• d.update([other])
  

  Update the dictionary with the key/value pairs from other,
  overwriting the existing keys. Return None.
  update() accepts either another dictionary object or an iterable of
  key/value pairs (as tuple or other iterables of length two).
  If the keyword arguments are specified, the dictionary is then updated
  with those key/value pairs: d.update(red=1, blue=2).

• d.setdefault(key[, default])
  

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

• d.get(key[, default])
  

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

• d.keys()
  

  Return a new view of the dictionary’s keys.

• d.values()
  

  Return a new view of the dictionary’s values.

• d.items()
  

  Return a new view of the dictionary’s items ((key, value) pairs).

Dictionaries compare equal if and only if they have the same (key, value) pairs.
Order comparisons(‘<’, ‘<=’, ‘>’, ‘>=’) raise TypeError.

• d.keys()
  

  Return a copy of dictionary’s list of keys.

• d.values()
  

  Return a copy of dictionary’s list of values.

• d.items()
  

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

• d.viewkeys()
  

  Return a new view of the dictionary’s keys.

• d.viewvalues()
  

  Return a new view of the dictionary’s values.

• d.viewitems()
  

  Return a new view of the dictionary’s items ((key, value) pairs).

• d.iterkeys()
  

  Return a iterator over the dictionary’s keys.

• d.itervalues()
  

  Return a iterator over the dictionary’s values.

• d.iteritems()
  

  Return a iterator over the dictionary’s (key, value) pairs.

• d.has_key(key)
  

  Test for the presence of key in the dictionary.
  has_key() is deprecated in favor of key in d.

The objects returned by dict.keys(), dict.values() and dict.items()
(Python2: dict.viewkeys(), dict.viewvalues() and dict.viewitems()) are view object.

They provide a dynamic view on the dictionary’s entries, which means that
when dictionary change, the view reflects these changes.

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# Python3
d = {'a': 1, 'b': 2, 'c': 3, 'd': 4}
keys = d.keys()
print(keys) # ['a', 'b', 'c', 'd']
del d['d']
print(keys) # ['a', 'b', 'c']

• len(dictview)

  Return the number of entries in the dictionary.

• iter(dictview)
  

  Return an iterator over the keys, values or items
  (represented as tuples of (key, value)) in the dictionary.

Iterating views while adding or deleting entries in the dictionary may
raise a RuntimeError or fail to iterate over all entries.

• x in dictview
  

  Return True if x is in the underlying dictionary’s keys, values or
  items (in the latter case, x should be a (key, value) tuple).

Keys and items views are set-like since their entries are unique and hashable.
Values views are not treated as set-like since the entries are generally not unique.
For set-like views, all of the operations defined for the set are available(e.g. &, |, -, ^).