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First solution in Clear category for Sort Array by Element Frequency by MSL
def sortbyfreq(item):
return -item[1], item[2]
def frequency_sort(items):
d = [[item, items.count(item), items.index(item)] for item in items]
return [item[0] for item in sorted(d, key = sortbyfreq)]
if __name__ == '__main__':
print("Example:")
print(frequency_sort([4, 6, 2, 2, 6, 4, 4, 4]))
# These "asserts" are used for self-checking and not for an auto-testing
assert list(frequency_sort([4, 6, 2, 2, 6, 4, 4, 4])) == [4, 4, 4, 4, 6, 6, 2, 2]
assert list(frequency_sort(['bob', 'bob', 'carl', 'alex', 'bob'])) == ['bob', 'bob', 'bob', 'carl', 'alex']
assert list(frequency_sort([17, 99, 42])) == [17, 99, 42]
assert list(frequency_sort([])) == []
assert list(frequency_sort([1])) == [1]
assert list(frequency_sort([4,6,2,2,2,6,4,4,4])) == [4,4,4,4,2,2,2,6,6]
print("Coding complete? Click 'Check' to earn cool rewards!")
Feb. 6, 2019