python基础（三）——正则表达式

import re
#匹配abc
m = re.findall("abc", "aabbccabccbaccbaaabcabc")
print(m)
#匹配一位数字，digit
m = re.findall("\d", "123abc1a2b3c1b2c3a")
print(m)
#匹配四位数字
m = re.findall("\d\d\d\d", "123abc1234ab12345c")
print(m)
#贪婪匹配
m = re.findall("<div>(.*)</div>", "<div>hello</div>")
print(m)
m = re.findall("<div>(.*)</div>",     "<div>hello</div><div>world</div>")
print(m)
#非贪婪匹配
m = re.findall("<div>(.*?)</div>",     "<div>hello</div><div>world</div>")
print(m)
#除换行符以外的所有字符
m = re.findall(".", "asdd\ndwjh\r")
print(m)
#转义字符
m = re.findall("\.", "a.c")
print(m)
#字符集，匹配中括号中任意一个字符
m = re.findall("a[bc]d", "abcdabdacdabbsdad")
print(m)
#数字
m = re.findall("\d", "abc1a2a32b")
print(m)
#非数字
m = re.findall("\D", "abc1a2a32b#")
print(m)
#空白字符
m = re.findall("\s", "abc a\na\r asd")
print(m)
#非空白字符
m = re.findall("\S", "abc a\na\r asd")
print(m)
#数字&字母
m = re.findall("\w", "ald!@n12\n1s\rk13")
print(m)
#非数字*字母
m = re.findall("\W", "ald!@n12\n1s\rk13")
print(m)
#匹配开头
m = re.findall("^abc", "abccbaabc")
print(m)
#匹配结尾
m = re.findall("cba$", "cbaabccba")
print(m)
#不区分大小写re.I
m = re.findall("abc", "AbcaBcabC", re.I)
print(m)
#匹配换行符&组合使用re.I
s = "<dIv>hello\nworld</DIV>"
m = re.findall(r"<div>(.*)</div>", s, re.S | re.I)
print(m)
#匹配多行
m = re.findall("^abc", "abc\nabc")
print(m)
m = re.findall("^abc", "abc\nabc", re.M)
print(m)
#匹配0或1个
m = re.findall("ab?", "abbbabbaaab")
print(m)
#匹配至少1个
m = re.findall("ab+", "abbbabbaaab")
print(m)
#匹配至少0个
m = re.findall("ab*", "abbbabbaaab")
print(m)
#实例：匹配邮箱
mail = "qq4786@qq.com"
m = re.findall("\w+@\w+\.com", mail)
print(m)
#先编译后使用
a = re.compile("\w+@\w+\.com")
m = a.findall("4786@qq.com")
n = a.findall("lir208@163.com")
print(m, n) 

---

输出结果：

['abc', 'abc', 'abc']
['1', '2', '3', '1', '2', '3', '1', '2', '3']
['1234', '1234']
['hello']
['hello</div><div>world']
['hello', 'world']
['a', 's', 'd', 'd', 'd', 'w', 'j', 'h', '\r']
['.']
['abd', 'acd']
['1', '2', '3', '2']
['a', 'b', 'c', 'a', 'a', 'b', '#']
[' ', '\n', '\r', ' ']
['a', 'b', 'c', 'a', 'a', 'a', 's', 'd']
['a', 'l', 'd', 'n', '1', '2', '1', 's', 'k', '1', '3']
['!', '@', '\n', '\r']
['abc']
['cba']
['Abc', 'aBc', 'abC']
['hello\nworld']
['abc']
['abc', 'abc']
['ab', 'ab', 'a', 'a', 'ab']
['abbb', 'abb', 'ab']
['abbb', 'abb', 'a', 'a', 'ab']
['qq4786@qq.com']
['4786@qq.com'] ['lir208@163.com']