词频统计 python

词频统计是指统计一段文本中各个单词出现的频率。在Python中，有多种方法可以实现词频统计。其中一种方法是使用集合去重和列表的count方法来统计频数，然后将结果按照出现次数进行排序。另一种方法是使用字典来统计单词出现的次数，然后根据次数进行排序。还有一种方法是使用计数器来实现词频统计。

方法一：

def word_count1(words, n):
    word_list = []
    for word in set(words):
        num = words.count(word)
        word_list.append([word, num])
    word_list.sort(key=lambda x: x[1], reverse=True)
    for i in range(n):
        word, count = word_list[i]
        print("{0:<15}{1:>5}".format(word, count))

方法二：

def word_count2(words, n):
    counts = {}
    for word in words:
        if len(word) == 1:
            continue
        else:
            counts[word] = counts.get(word, 0) + 1
    items = list(counts.items())
    items.sort(key=lambda x: x[1], reverse=True)
    for i in range(n):
        word, count = items[i]
        print("{0:<15}{1:>5}".format(word, count))

方法三：

def word_count3(words, n):
    from collections import Counter
    counts = Counter(words)
    for ch in "":
        del counts[ch]
    for word, count in counts.most_common(n):
        print("{0:<15}{1:>5}".format(word, count))