Create a dictionary with list comprehension

Question

I like the Python list comprehension syntax.

Can it be used to create dictionaries too? For example, by iterating over pairs of keys and values:

mydict = {(k,v) for (k,v) in blah blah blah}  # doesn't work 

Answer 1

Use a dict comprehension (Python 2.7 and later):

{key: value for (key, value) in iterable} 

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Alternatively for simpler cases or earlier version of Python, use the dict constructor, e.g.:

pairs = [('a', 1), ('b', 2)] dict(pairs)                         #=> {'a': 1, 'b': 2} dict([(k, v+1) for k, v in pairs])  #=> {'a': 2, 'b': 3} 

Given separate arrays of keys and values, use the dict constructor with zip:

keys = ['a', 'b'] values = [1, 2] dict(zip(keys, values))  #=> {'a': 1, 'b': 2} 

2) "zip'ped" from two separate iterables of keys/vals dict(zip(list_of_keys, list_of_values)) 

Answer 2

In Python 3 and Python 2.7+, dictionary comprehensions look like the below:

d = {k:v for k, v in iterable} 

For Python 2.6 or earlier, see fortran's answer.