Table of Contents
The dict() constructor creates a dictionary in Python.
Different forms of dict()
constructors are:
class dict(**kwarg) class dict(mapping, **kwarg) class dict(iterable, **kwarg)
Note: **kwarg
let you take an arbitrary number of keyword arguments.
A keyword argument is an argument preceded by an identifier (eg. name=
). Hence, the keyword argument of the form kwarg=value
is passed to dict()
constructor to create dictionaries.
dict()
doesn’t return any value (returns None
).
1. Example 1: Create Dictionary Using keyword arguments only
numbers = dict(x=5, y=0) print('numbers =', numbers) print(type(numbers)) empty = dict() print('empty =', empty) print(type(empty))
Output
numbers = {'y': 0, 'x': 5} <class 'dict'> empty = {} <class 'dict'>
2. Example 2: Create Dictionary Using Iterable
# keyword argument is not passed numbers1 = dict([('x', 5), ('y', -5)]) print('numbers1 =',numbers1) # keyword argument is also passed numbers2 = dict([('x', 5), ('y', -5)], z=8) print('numbers2 =',numbers2) # zip() creates an iterable in Python 3 numbers3 = dict(dict(zip(['x', 'y', 'z'], [1, 2, 3]))) print('numbers3 =',numbers3)
Output
numbers1 = {'y': -5, 'x': 5} numbers2 = {'z': 8, 'y': -5, 'x': 5} numbers3 = {'z': 3, 'y': 2, 'x': 1}
3. Example 3: Create Dictionary Using Mapping
numbers1 = dict({'x': 4, 'y': 5}) print('numbers1 =',numbers1) # you don't need to use dict() in above code numbers2 = {'x': 4, 'y': 5} print('numbers2 =',numbers2) # keyword argument is also passed numbers3 = dict({'x': 4, 'y': 5}, z=8) print('numbers3 =',numbers3)
Output
numbers1 = {'x': 4, 'y': 5} numbers2 = {'x': 4, 'y': 5} numbers3 = {'x': 4, 'z': 8, 'y': 5}
Recommended Reading: Python dictionary and how to work with them.
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