python - 索引错误: list assignment index out of range Python

Question

def mode(given_list):
    highest_list = []
    highest = 0
    index = 0
    for x in range(0, len(given_list)):
        occurrences = given_list.count(given_list[x])
        if occurrences > highest:
            highest = occurrences
            highest_list[0] = given_list[x]
        elif occurrences == highest:
            highest_list.append(given_list[x])

该代码旨在计算出给定列表的模式。我不明白我哪里出了问题。

我收到的确切错误。

line 30, in mode
    highest_list[0] = given_list[x]
IndexError: list assignment index out of range

Answer 1

问题是你原来有一个空列表:

highest_list = []

然后在循环中尝试在索引 0 处访问它:

highest_list[0] = ...

这是不可能的，因为它是一个空列表，因此在位置 0 处不可索引。

查找列表模式的更好方法是使用 collections.Counter 对象:

>>> from collections import Counter
>>> L = [1,2,3,3,4]
>>> counter = Counter(L)
>>> max(counter, key=counter.get)
3
>>> [(mode, n_occurrences)] = counter.most_common(1)
>>> mode, n_occurrences
(3, 2)