Читать книгу Algorithms For Dummies - John Paul Mueller, John Mueller Paul, Luca Massaron - Страница 91

Repeated data can unfairly weight the output of an algorithm so that you get inaccurate results. Sometimes you need unique values to determine the outcome of a data manipulation. Fortunately, Python makes it easy to remove certain types of repeated data. Consider this example:

a = np.array([1,2,3,4,5,6,6,7,7,1,2,3])b = np.array(list(set(a))) print(b)

The output contains only the unique elements:

[1, 2, 3, 4, 5, 6, 7]

In this case, a begins with an assortment of numbers in no particular order and with plenty of repetitions. In Python, a set never contains repeated data. Consequently, by converting the list in a to a set and then back to a list, and then placing that list in an array, you obtain a vector that has no repeats.