How to extract dictionary single key-value pair in variables

dictionary, iterable-unpacking, python, python-2.7

Solution

Add another level, with a tuple (just the comma):

(k, v), = d.items()

or with a list:

[(k, v)] = d.items()

or pick out the first element:

k, v = d.items()[0]

The first two have the added advantage that they throw an exception if your dictionary has more than one key, and both work on Python 3 while the latter would have to be spelled as `k, v = next(iter(d.items()))` to work.

Demo:

>>> d = {'foo': 'bar'}
>>> (k, v), = d.items()
>>> k, v
('foo', 'bar')
>>> [(k, v)] = d.items()
>>> k, v
('foo', 'bar')
>>> k, v = d.items()[0]
>>> k, v
('foo', 'bar')
>>> k, v = next(iter(d.items()))  # Python 2 & 3 compatible
>>> k, v
('foo', 'bar')

Problem

I have only a single key-value pair in a dictionary. I want to assign key to one variable and it's value to another variable. I have tried with below ways but I am getting error for same. ``` >>> d = {"a": 1} >>> d.items() [('a', 1)] >>> (k, v) = d.items() Traceback (most recent call last): File "<stdin>", line 1, in <module> ValueError: need more than 1 value to unpack >>> (k, v) = list(d.items()) Traceback (most recent call last): File "<stdin>", line 1, in <module> ValueError: need more than 1 value to unpack ``` I know that we can extract key and value one by one, or by for loop and `iteritems()`, but isn't there a simple way such that we can assign both in a single statement?

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