This is part of a large trend in python to use more iterators (and generators), rather than copies of lists all over the place.ĭict.keys() should work with comprehensions, though - check carefully for typos or something. Very similarly for zip() - in the vast majority of cases, it is iterated through - why create an entire new list of tuples just to iterate through it and then throw it away again? And if you do need them as a list you can call list(). In real use-cases, the most common thing to do with the keys in a dict is to iterate through them, so this makes sense. a list is also an iterable, but an iterable is NOT a list (or sequence.) It will work anywhere an iterable will work - not any place a list will. In a similar fashion, you can create tuples and sets of dictionary keys: > *newdict,īeware of the trailing comma in the tuple case!Ī bit off on the "duck typing" definition - dict.keys() returns an iterable object, not a list-like object.
With larger dictionaries the speed is pretty much the same (the overhead of iterating through a large collection trumps the small cost of a function call). Though equivalent to list(newdict) with the difference that it's faster (at least for small dictionaries) because no function call is actually performed: %timeit ġ000000 loops, best of 3: 249 ns per loopġ000000 loops, best of 3: 508 ns per loopġ000000 loops, best of 3: 574 ns per loop
#Where are the last 3 small keys in obscure 2 manual#
With PEP 448 the restriction on where *iterable could appear was loosened allowing it to also be placed in list, set and tuple literals, the reference manual on Expression lists was also updated to state this. The *iterable syntax is similar to doing list(iterable) and its behaviour was initially documented in the Calls section of the Python Reference manual. (which, in all honesty, isn't something you should really be worried about). keys() i.e might help in making your intent a bit more explicit though it will cost you a function look-up and invocation. Unpacking with * works with any object that is iterable and, since dictionaries return their keys when iterated through, you can easily create a list by using it within a list literal.Īdding. And of course, watching videos on YouTube. They’re reading all the articles, watching all the webinars, and signing up for all the newsletters.
3 The country was known for its prosperous phosphate mining operations in the early 20th century. Nauru is the world's smallest island country with an area of just 8.5 square miles and a population of about 11,000 people. New unpacking generalizations (PEP 448) were introduced with Python 3.5 allowing you to now easily do: > newdict = This is usually the beginning of a person’s journey of recovery from narcissistic abuse. Nauru is a small island nation located in the South Pacific Ocean in the region of Oceania. Python >= 3.5 alternative: unpack into a list literal
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