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I have a list say a = [5,3,1,4,10]. I need to get indices of the top two values of the list, that is for 5 and 10 I would get [0, 4]. Is there a one-liner that Python offers for such a case?
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In order to get the indices of N maximum values in a NumPy array, we can use the argsort() function.
By using the list. index() method, we can easily get the element index value from list. In this example we have define a list of integer values and uses the list. index() method we can get the index of the item whose value is '210'.
Method #1 : Using sorted() + lambda The combination of above functionality can be used to perform this particular task. In this, we just employ sorted function with reverse flag true, and print the top N elements using list slicing.
If you want to get the indices of the three largest values, you can just slice the list. It also supports sorting from smallest to largest by using the parameter rev=False .
sorted(range(len(a)), key=lambda i: a[i])[-2:] or
sorted(range(len(a)), key=lambda i: a[i], reverse=True)[:2] or
import operator zip(*sorted(enumerate(a), key=operator.itemgetter(1)))[0][-2:] or (for long lists), consider using heapq.nlargest
zip(*heapq.nlargest(2, enumerate(a), key=operator.itemgetter(1)))[0] Just a NumPy alternative:
import numpy as np top_2_idx = np.argsort(a)[-2:] top_2_values = [a[i] for i in top_2_idx] If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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