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I recently encountered a scenario in which if a set only contained a single element, I wanted to do something with that element. To get the element, I settled on this approach:
element = list(myset)[0] But this isn't very satisfying, as it creates an unnecessary list. It could also be done with iteration, but iteration seems unnatural as well, since there is only a single element. Am I missing something simple?
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To retrieve all elements from a set, you can use a simple for-loop. Another approach is to create an iterator object and retrieve the items from it using the next() function. The next() function raises StopIteration when the iterator is exhausted. You can also supply a default value to the next() function.
You cannot access items in a set by referring to an index or a key. But you can loop through the set items using a for loop, or ask if a specified value is present in a set, by using the in keyword.
Using Python's import numpy, the unique elements in the array are also obtained. In the first step convert the list to x=numpy. array(list) and then use numpy. unique(x) function to get the unique values from the list.
Tuple unpacking works.
(element,) = myset (By the way, python-dev has explored but rejected the addition of myset.get() to return an arbitrary element from a set. Discussion here, Guido van Rossum answers 1 and 2.)
My personal favorite for getting an arbitrary element is (when you have an unknown number, but also works if you have just one):
element = next(iter(myset)) ¹ 1: in Python 2.5 and before, you have to use iter(myset).next()
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