python一些东西
assert repr()
1 >>> a 2 ['d', 'c', 'c', 'f', 'a', 'a', 'b', 'c', 'd'] 3 >>> sorted(a) 4 ['a', 'a', 'b', 'c', 'c', 'c', 'd', 'd', 'f'] 5 >>> from collections import Counter 6 >>> a_counter = Counter(a) 7 >>> a_counter 8 Counter({'c': 3, 'd': 2, 'a': 2, 'f': 1, 'b': 1}) 9 >>> a_counter.update(["d","d"]) 10 >>> a_counter 11 Counter({'d': 4, 'c': 3, 'a': 2, 'f': 1, 'b': 1}) 12 >>> type(a_counter) 13 <class 'collections.Counter'> 14 >>> a_counter.most_common(3) 15 [('d', 4), ('c', 3), ('a', 2)]
1 #round() 方法返回浮点数x的四舍五入值。 2 3 round(70.23456) : 70 4 round(56.659,1) : 56.7 5 round(80.264, 2) : 80.26 6 round(100.000056, 3) : 100.0 7 round(-100.000056, 3) : -100.0
