How can I convert a dictionary into a list of tuples?

Question

>>> d = { 'a': 1, 'b': 2, 'c': 3 }
>>> list(d.items())
[('a', 1), ('c', 3), ('b', 2)]

For Python 3.6 and later, the order of the list is what you would expect.

In Python 2, you don't need list.

since no one else did, I'll add py3k versions:

>>> d = { 'a': 1, 'b': 2, 'c': 3 }
>>> list(d.items())
[('a', 1), ('c', 3), ('b', 2)]
>>> [(v, k) for k, v in d.items()]
[(1, 'a'), (3, 'c'), (2, 'b')]

You can use list comprehensions.

[(k,v) for k,v in a.iteritems()] 

will get you [ ('a', 1), ('b', 2), ('c', 3) ] and

[(v,k) for k,v in a.iteritems()] 

the other example.

Read more about list comprehensions if you like, it's very interesting what you can do with them.

Create a list of namedtuples

It can often be very handy to use namedtuple. For example, you have a dictionary of 'name' as keys and 'score' as values like:

d = {'John':5, 'Alex':10, 'Richard': 7}

You can list the items as tuples, sorted if you like, and get the name and score of, let's say the player with the highest score (index=0) very Pythonically like this:

>>> player = best[0]

>>> player.name
        'Alex'
>>> player.score
         10

How to do this:

list in random order or keeping order of collections.OrderedDict:

import collections
Player = collections.namedtuple('Player', 'name score')
players = list(Player(*item) for item in d.items())

in order, sorted by value ('score'):

import collections
Player = collections.namedtuple('Player', 'score name')

sorted with lowest score first:

worst = sorted(Player(v,k) for (k,v) in d.items())

sorted with highest score first:

best = sorted([Player(v,k) for (k,v) in d.items()], reverse=True)

[(k,v) for (k,v) in d.iteritems()]

and

[(v,k) for (k,v) in d.iteritems()]