【初学python】实例九：词频统计

今天我们来统计一下一本书里面的一些关键字。
这里首先忽略了一个问题：这是一本什么书？中文？还是英文？
如果是英文，我们要解决的问题有很多：比如说大小写问题，标点符号问题等等，首先我们在网上下载一个全英的TXT文本（这里以莎士比亚的哈姆雷特为蓝本），然后我们给出代码：

#实例9：词频统计
def gettext():
    txt = open("471228.txt","r",encoding="utf-8").read()
    txt = txt.lower()
    for ch in '|\/*-+.!@#$%^&*()''/.,?><"~`':
        txt = txt.replace(ch," ")
    return txt
hamlettxt = gettext()
words = hamlettxt.split()
counts = {}
for word in words:
    counts[word] = counts.get(word,0) +1
items = list(counts.items())
items.sort(key = lambda x:x[1],reverse = True)
for i in range(10):
    word,count = items[i]
    print("{0:<10}{1:>5}".format(word,count))

运行效果：

类似的，我们给出中文版式的名著《三国演义》，要求统计人物姓名的出场次数，相比于英文版，这个比较简单，因为不存在大小写问题，这里我们引入了一个非常优秀的第三方库函数：jieba，如果我们按照上面的格式来编程：

#实例9：词频统计
import jieba
txt = open("三国演义.txt","r",encoding = "gb18030").read()
words = jieba.lcut(txt)
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(15):
    word,count = items[i]
    print("{0:<10}{1:>5}".format(word,count))

运行效果确是这样的：

我们发现：这里的很多词并不是人名，因此我们需要对程序进行改进：
1.将前十以内的不是人名的剔除
2.将同一个人的不同称呼与这个人相关联
于是 2.0 版本正式诞生：

#实例9：词频统计
import jieba
txt = open("三国演义.txt","r",encoding = "gb18030").read()
excludes = {"将军","却说","荆州","二人","不可","不能","如此","商议","如何","主公","军士","吕布","左右","军马","引兵","次日","大喜","天下","东吴","于是","不敢","人马","都督","一人","魏兵","陛下","今日"}
words = jieba.lcut(txt)
counts = {}
for word in words:
    if len(word) ==1:
        continue
    elif word=="诸葛亮" or word == "孔明曰":
        rword = "孔明"
    elif word=="关公" or word == "关云长":
        rword = "关羽"
    elif word=="玄德" or word == "玄德曰":
        rword = "刘备"
    elif word=="孟德" or word == "丞相":
        rword = "曹操"
    else:
        rword = word
    counts[rword] = counts.get(rword,0) + 1
for word in excludes:
    del counts[word]
items = list(counts.items())
items.sort(key = lambda x:x[1],reverse = True)
for i in range(10):
    word,count = items[i]
    print("{0:<10}{1:>5}".format(word,count))

运行结果：重磅发布！三国演义前十名英雄人物！

同样的：
《西游记》呢？
《红楼梦》呢？
留给你做思考呦