python正则表达式（三）

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表示边界

示例1：$

需求：匹配163.com的邮箱地址

#coding=utf-8

import re

# 正确的地址

ret = re.match("[\w]{4,20}@163\.com", "xiaoWang@163.com")

ret.group()

# 不正确的地址

ret = re.match("[\w]{4,20}@163\.com", "xiaoWang@163.comheihei")

ret.group()

# 通过$来确定末尾

ret = re.match("[\w]{4,20}@163\.com$", "xiaoWang@163.comheihei")

ret.group()

示例2: \b

>>> re.match(r".*\bver\b", "ho ver abc").group()

'ho ver'

>>> re.match(r".*\bver\b", "ho verabc").group()

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

AttributeError: 'NoneType' object has no attribute 'group'

>>> re.match(r".*\bver\b", "hover abc").group()

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

AttributeError: 'NoneType' object has no attribute 'group'

示例3：\B

>>> re.match(r".*\Bver\B", "hoverabc").group()

'hover'

>>> re.match(r".*\Bver\B", "ho verabc").group()

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

AttributeError: 'NoneType' object has no attribute 'group'

>>> re.match(r".*\Bver\B", "hover abc").group()

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

AttributeError: 'NoneType' object has no attribute 'group'

>>> re.match(r".*\Bver\B", "ho ver abc").group()

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

AttributeError: 'NoneType' object has no attribute 'group'

匹配分组

示例1：|

需求：匹配出0-100之间的数字

#coding=utf-8

import re

ret = re.match("[1-9]?\d","")

ret.group()

ret = re.match("[1-9]?\d","")

ret.group()

# 不正确的情况

ret = re.match("[1-9]?\d","")

ret.group()

# 修正之后的

ret = re.match("[1-9]?\d$","")

ret.group()

# 添加|

ret = re.match("[1-9]?\d$|100","")

ret.group()

ret = re.match("[1-9]?\d$|100","")

ret.group()

ret = re.match("[1-9]?\d$|100","")

ret.group()

ret = re.match("[1-9]?\d$|100","")

ret.group()

示例2：( )

需求：匹配出163、126、qq邮箱之间的数字

#coding=utf-8

import re

ret = re.match("\w{4,20}@163\.com", "test@163.com")

ret.group()

ret = re.match("\w{4,20}@(163|126|qq)\.com", "test@126.com")

ret.group()

ret = re.match("\w{4,20}@(163|126|qq)\.com", "test@qq.com")

ret.group()

ret = re.match("\w{4,20}@(163|126|qq)\.com", "test@gmail.com")

ret.group()