Python核心编程 第三版 - 正则表达式部分习题

运行下列脚本需要导入的模块

import os
import re
from random import choice, randrange
from string import ascii_lowercase as lc
from sys import maxsize
from time import ctime
from collections import Counter

1 - 择一匹配符的使用

pattern = r'[bh][aiu]t'
result = re.match(pattern, 'bat')
print(result.group())
result = re.match(pattern, 'hut')
print(result.group())

2 - 匹配单个空格分隔的任意单词对

pattern = r'([A-Za-z]+) ([A-Za-z]+)'
result = re.match(pattern, 'Hello World')
print(result.groups())

3 - 匹配单个逗号和单个空白符分隔的单词和字母

pattern = r'([A-Za-z]+), ([A-Za-z])'
result = re.match(pattern, 'Jonathan, Lim')
print(result.groups())

4 - Python标识符

pattern = r'[_A-Za-z][_A-Za-z0-9]+'
result = re.findall(pattern, '_helo __hello _ 34 34_naming naming naming____')
print(result)

6 - 匹配以www.开始，以.com|.net|.edu结尾的网址

pattern = r'www\.([A-Za-z0-9]+\.)+(com|net|edu|cn)'
result = re.match(pattern, 'www.baidu.com')
print(result.group())
result = re.match(pattern, 'www.upc.edn.cn')
print(result.group())

13 - 根据类型字符串吗，提取类型。类型可以通过type()来获取，python2中，类型字符串的格式为<type 'xxx'>；Python3中，类型字符串的格式为<class 'xxx'>

pattern = r'''<(type|class) '(\w+)'>'''
result = re.match(pattern, str(type('')))
print(result.group(2))

14 - 匹配月份

pattern = r'0?[1-9]$|1[0-2]$'
result = re.match(pattern, '03')
print(result.group())
result = re.match(pattern, '12')
print(result.group())

15 - 处理信用卡号码。美国信用卡是由15或者16位数字组成。格式可以是：4-6-5或者是4-4-4-4

pattern = r'\d{4}-\d{6}-\d{5}|(\d{4}-){3}\d{4}'
result = re.match(pattern, '4345-456278-34234')
print(result.group())
result = re.match(pattern, '4345-6278-3423-9909')
print(result.group())

16 - 为gendata.py更新代码，使得结果输出到redata.txt上

tlds = ('com', 'edu', 'net', 'org', 'gov')
with open('redata.txt', 'at') as file:
    for i in range(randrange(5, 11)):
        dtint = randrange(maxsize)  # pick date (seconds from 'epoch')
        dtstr = ctime(dtint)  # date string
        llen = randrange(4, 8)  # login is shorter
        login = ''.join(choice(lc) for j in range(llen))
        dlen = randrange(llen, 13)  # domain is longer
        dom = ''.join(choice(lc) for j in range(llen))
        print('%s::%s@%s.%s::%d-%d-%d' % (dtstr, login, dom, choice(tlds), dtint, llen, dlen), file=file)

def read_textfile(filename):
    with open(filename, 'rt') as file:
        return file.readlines().__str__()

17 - 统计redata.txt.中，一周的每一天出现的次数

pattern = r'(^\w{3})'
resultDic = Counter()
with open('redata.txt', 'rt') as file:
    for line in file:
        key = re.match(pattern, line).group(1)
        resultDic[key] += 1
print(resultDic)

19 - 提取每行中完整的时间戳

pattern = r'(\w{3} \w{3} \d?\d \d{2}:\d{2}:\d{2} \d{4})'
result = re.findall(pattern, read_textfile('redata.txt'))
print(result)

20 - 提取每行中完整的邮件地址

pattern = r'(\w+@\w+\.(edu|com|net|org|gov))'
result = re.findall(pattern, read_textfile('redata.txt'))
print(result)

21 - 仅仅提取时间戳中的月份

pattern = r'\w{3} (\w{3}) \d?\d'
result = re.findall(pattern, read_textfile('redata.txt'))
print(result)

22 - 仅仅提取时间戳中的年份

pattern = r'\d{4}'
result = re.findall(pattern, read_textfile('redata.txt'))
print(result)

23 - 仅仅提取时间戳中的时间

pattern = r'\d\d:\d\d:\d\d'
result = re.findall(pattern, read_textfile('redata.txt'))
print(result)

24 - 仅仅从电子邮件地址中提取登录名和域名 （主域名和高级域名）

pattern = r'::(\w+)@(\w+\.\w+)::'
result = re.findall(pattern, read_textfile('redata.txt'))
print(result)

25 - 仅仅从电子邮件地址中提取登录名和域名

pattern = r'::(\w+)@(\w+)\.\w+::'
result = re.findall(pattern, read_textfile('redata.txt'))
print(result)

26 - 使用你的电子邮件替换每一行数据中的电子邮件地址

pattern = r'\w+@\w+\.(edu|com|net|org|gov)'
result = re.sub(pattern, 'jonlimx@hotmail.com', read_textfile('redata.txt'))
print(result)

27 - 从时间戳中提取月，日和年，然后以“月，日，年”的格式，每一行仅仅迭代一次

pattern = r'(?P<month>\w{3}) (?P<day>\w{3})'
with open('redata.txt', 'rt') as file:
    for line in file:
        result = re.sub(pattern, '\g<day> \g<month>', line)
        print(result)

os.remove('redata.txt')

28, 29 - 处理电话号码，格式为：三位数字区号 - 三位数字 - 四位数字，需要满足以下两个条件：
1. 区号可以省略，也就是可以匹配 800-555-1212，也能匹配555-1212
2. 支持使用圆括号或者连字符连接区号，也就是可以匹配800-555-1212， 555-1212以及(800) 555-1212

pattern = r'(\(?\d{3}\)?[-\s])?(\d{3})-(\d{4})'
print(re.match(pattern, '800-555-1212').group())
print(re.match(pattern, '555-1212').group())
print(re.match(pattern, '(800) 555-1212').group())