3-2 从单词中获取单词出现的频率信息，并把他们写进对应的列表里

流畅的python字典中的示例3-2

创建一个单词从其出现情况的映射

import sys
import re

WORD_RE = re.compile(r'\w+')

index = {}

with open(sys.argv[1], encoding='utf-8') as fp:
    for line_no, line in enumerate(fp, 1):
        for match in WORD_RE.finditer(line):
            word = match.group()
            column_no = match.start() + 1
            location = (line_no, column_no)
            occurrences = index.get(word, [])
            occurrences.append(location)
            index[word] = occurrences

for word in sorted(index, key=str.upper):
    print(word, index[word])

【理解点】

• sys.argv[1]的作用是什么？如何使用？
• enumerate()函数的作用是什么，如何使用？
• word的查询频率是什么？

【运行结果】

# 在index0.py下创建一个aa.txt文件，存入单词
F:\python_interface_test\python_interface_test\prepare_data>python index0.py aa.txt
16 [(14, 19)]
2006 [(11, 93)]
21 [(1, 51)]
21st [(8, 29)]
27 [(1, 41)]
a [(2, 60), (5, 30), (6, 73)]
against [(4, 61)]

 

【优化】

import sys
import re

WORD_RE = re.compile(r'\w+')

index = {}

with open(sys.argv[1], encoding='utf-8') as fp:
    for line_no, line in enumerate(fp, 1):
        for match in WORD_RE.finditer(line):
            word = match.group()
            column_no = match.start() + 1
            location = (line_no, column_no)
            
            index.setdefault(word, []).append(location )

for word in sorted(index, key=str.upper):
    print(word, index[word])