def isPhoneNumber(text):
if len(text) != 11:
return False
for i in range(0, len(text)):
if (i == 3 or i == 7) and text[i] != "-":
return False
elif i != 3 and i != 7 and not text[i].isdecimal():
return False
return True
text = "123-456-789"
print(text)
print(isPhoneNumber(text))
2. 用正则表达式来查找文本模式
2.1 创建正则表达式（Regex）对象
python复制代码
import re
text = re.compile(r'\d\d\d-\d\d\d-\d\d\d')
2.2 匹配Regex对象
python复制代码
import re
text = re.compile(r'\d\d\d-\d\d\d-\d\d\d')
match = text.search("~~~123-456-789~~~")
print(match.group())
3. 用正则表达式匹配更多模式
3.1 利用括号分组
python复制代码
import re
text = re.compile(r'(\d\d\d)-(\d\d\d-\d\d\d)')
match = text.search("~~~123-456-789~~~")
print(match.group(1))
# 123
print(match.group(2))
# 456-789
print(match.groups())
# ('123', '456-789')
3.2 用管道匹配多个分组
| ：管道
python复制代码
import re
text = re.compile(r'456|123')
match = text.search("123-456-789")
print(match.group())
# 123
3.3 用问号实现可选匹配
python复制代码
import re
text = re.compile(r'\d\d\d(~)?\d\d\d')
match = text.search("123123")
print(match.group())
# 123123
match = text.search("123~123")
print(match.group())
# 123~123
3.4 用星号匹配零次或多次
python复制代码
import re
text = re.compile(r'\d\d\d(~)*\d\d\d')
match = text.search("123123")
print(match.group())
# 123123
match = text.search("123~~~123")
print(match.group())
# 123~~~123
3.5 用加号匹配一次或多次
python复制代码
import re
text = re.compile(r'\d\d\d(~)+\d\d\d')
match = text.search("123~123")
print(match.group())
# 123~123
match = text.search("123~~~123")
print(match.group())
# 123~~~123
3.6 用花括号匹配特定次数
python复制代码
import re
text = re.compile(r'\d\d\d(~){3,5}\d\d\d')
match = text.search("123~~~123")
print(match.group())
# 123~~~123
match = text.search("123~~~~~123")
print(match.group())
# 123~~~~~123
4. 贪心和非贪心匹配
贪心匹配：尽可能匹配最长的字符串
非贪心匹配：尽可能匹配最短的字符串
python复制代码
import re
text = re.compile(r'(123 ){2,4}')
match = text.search("123 123 123 123 123 ")
print(match.group())
# 123 123 123 123
text = re.compile(r'(123 ){2,4}?')
match = text.search("123 123 123 123 123 ")
print(match.group())
# 123 123
5. findall() 方法
python复制代码
import re
text = re.compile(r'\d\d\d-\d\d\d-\d\d\d')
match = text.search("~~~123-456-789~~~111-222-333~~~")
print(match.group())
# 123-456-789
match = text.findall("~~~123-456-789~~~111-222-333~~~")
print(match)
# ['123-456-789', '111-222-333']
6. 字符分类
编写字符分类
表示
\d
0~9的任何数字
\D
除0~9的数字以外的任何字符
\w
任何字母、数字和下划线字符
\W
除字母、数字和下划线以外的任何字符
\s
空格、制表符或换行符
\S
除空格、制表符和换行符以外的任何字符
7. 建立自己的字符分类
python复制代码
import re
text = re.compile(r'[0-5]')
match = text.findall("1a2b3c4d")
print(match)
# ['1', '2', '3', '4']
text = re.compile(r'[abc]')
match = text.findall("1a2b3c4d")
print(match)
# ['a', 'b', 'c']
text = re.compile(r'[^abc]')
match = text.findall("1a2b3c4d")
print(match)
# ['1', '2', '3', '4', 'd']
8. 插入字符和美元字符
^ ：以指定文本开始
$ ：以指定文本结束
python复制代码
import re
text = re.compile(r'^\d\d\d')
match = text.search("123abc456")
print(match)
# <re.Match object; span=(0, 3), match='123'>
text = re.compile(r'\d\d\d$')
match = text.search("123abc456")
print(match)
# <re.Match object; span=(6, 9), match='456'>
9. 通配字符
. ：匹配换行符之外的所有字符
python复制代码
import re
text = re.compile(r'..23')
match = text.findall("123abc23")
print(match)
# ['bc23']
9.1 用点-星匹配所有字符
python复制代码
import re
text = re.compile(r'123(.*)456(.*)')
match = text.findall("123abc456def")
print(match)
# [('abc', 'def')]
9.2 用句点字符匹配换行符
re.DOTALL ：让句点字符匹配所有字符（包括换行符）
python复制代码
import re
text = re.compile(r'.*')
match = text.search("123abc\n456def")
print(match.group())
# 123abc
text = re.compile(r'.*', re.DOTALL)
match = text.search("123abc\n456def")
print(match.group())
# 123abc\n456def
10. 不区分大小写的匹配
re.I ：不区分大小写
python复制代码
import re
text = re.compile(r'abc', re.I)
match = text.findall("abcABC")
print(match)
# ['abc', 'ABC']
11. 用 sub() 方法替换字符串
python复制代码
import re
text = re.compile(r'ABC\w*')
match = text.sub("abc", "ABC : 123")
print(match)
# abc : 123