Built-in Functions In Python - Letter D

delattr(object, name)

The arguments are an object and a string. The string must be the name of one of the object’s attributes. The function deletes the named attribute, provided the object allows it. For example, delattr(x, 'foobar') is equivalent to del x.foobar.

class dict(**kwarg)

class dict(mapping, **kwarg)

class dict(iterable, **kwarg)

Create a new dictionary. The dict object is the dictionary class. See dict and Mapping Types — dict for documentation about this class.

For other containers see the built-in list, set, and tuple classes, as well as the collections module.                                                                                                                                                                   

dir([object])

Without arguments, return the list of names in the current local scope. With an argument, attempt to return a list of valid attributes for that object.

If the object has a method named __dir__(), this method will be called and must return the list of attributes. This allows objects that implement a custom __getattr__() or __getattribute__() function to customize the way dir() reports their attributes.

If the object does not provide __dir__(), the function tries its best to gather information from the object’s __dict__ attribute, if defined, and from its type object. The resulting list is not necessarily complete, and may be inaccurate when the object has a custom __getattr__().

The default dir() mechanism behaves differently with different types of objects, as it attempts to produce the most relevant, rather than complete, information:

If the object is a module object, the list contains the names of the module’s attributes.

If the object is a type or class object, the list contains the names of its attributes, and recursively of the attributes of its bases.

Otherwise, the list contains the object’s attributes’ names, the names of its class’s attributes, and recursively of the attributes of its class’s base classes.

The resulting list is sorted alphabetically. For example:

>>>

>>> import struct

>>> dir()   # show the names in the module namespace

['__builtins__', '__doc__', '__name__', 'struct']

>>> dir(struct)   # show the names in the struct module

['Struct', '__builtins__', '__doc__', '__file__', '__name__',

 '__package__', '_clearcache', 'calcsize', 'error', 'pack', 'pack_into',

 'unpack', 'unpack_from']

>>> class Shape(object):

        def __dir__(self):

            return ['area', 'perimeter', 'location']

>>> s = Shape()

>>> dir(s)

['area', 'perimeter', 'location']

Note Because dir() is supplied primarily as a convenience for use at an interactive prompt, it tries to supply an interesting set of names more than it tries to supply a rigorously or consistently defined set of names, and its detailed behavior may change across releases. For example, metaclass attributes are not in the result list when the argument is a class.                   

divmod(a, b)

Take two (non complex) numbers as arguments and return a pair of numbers consisting of their quotient and remainder when using long division. With mixed operand types, the rules for binary arithmetic operators apply. For plain and long integers, the result is the same as (a // b, a % b). For floating point numbers the result is (q, a % b), where q is usually math.floor(a / b) but may be 1 less than that. In any case q * b + a % b is very close to a, if a % b is non-zero it has the same sign as b, and 0 <= abs(a % b) < abs(b).

Changed in version 2.3: Using divmod() with complex numbers is deprecated.

enumerate(sequence, start=0)

Return an enumerate object. sequence must be a sequence, an iterator, or some other object which supports iteration. The next() method of the iterator returned by enumerate() returns a tuple containing a count (from start which defaults to 0) and the values obtained from iterating oversequence:

>>>

>>> seasons = ['Spring', 'Summer', 'Fall', 'Winter']

>>> list(enumerate(seasons))

[(0, 'Spring'), (1, 'Summer'), (2, 'Fall'), (3, 'Winter')]

>>> list(enumerate(seasons, start=1))

[(1, 'Spring'), (2, 'Summer'), (3, 'Fall'), (4, 'Winter')]

Equivalent to:

def enumerate(sequence, start=0):

    n = start

    for elem in sequence:

        yield n, elem

        n += 1