第11章总体程序

首先是测试文本，为了有效验证结果是否正确，使用'new.txt'文件如下
I do love you.
Do you love me?
Yes, I do.

（注意最后一句写完之后也要回车，保证存在n）

程序：

# wordstats.py
keep={'a','b','c','d','e','f','g',
      'h','i','j','k','l','m','n',
      'o','p','q','r','s','t','u',
      'v','w','x','y','z',' ','-',"'",'n'}

def normalize(s):
    result=''
    for c in s.lower():
        if c in keep:
            result=result+c
    return result

def make_freq_dict(s):
    s=normalize(s)
    words=s.split()
    d={}
    for w in words:
        if w in d:
            d[w]+=1
        else:
            d[w]=1
    return d

def print_file_stats(fname):
    s=open(fname,'r').read()
    num_chars=len(s)
    num_lines=s.count('n')
    d=make_freq_dict(s)
    num_words=sum(d[w] for w in d)

    lst=[(d[w],w) for w in d]
    lst.sort()
    lst.reverse()

    print("The file '%s' has: "%fname)
    print(' ',str(num_chars),' characters')
    print(' ',str(num_lines),' lines')
    print(' ',str(num_words),' words')

    print("nThe top 10 most frequent words are:")
    i=1
    for count, word in lst[:10]:
        print('No.'+str(i),count,word)
        i+=1
   
IDLE shell结果

>>> print_file_stats('new.txt')
The file 'new.txt' has:
     42 characters
     3 lines
     11 words

The top 10 most frequent words are:
No.1 3 do
No.2 2 you
No.3 2 love
No.4 2 i
No.5 1 yes
No.6 1 me