import re

m = re.match(r'(\w+) (\w+)(?P<sign>.*)', 'hello world!')

print("m.string:", m.string)

print("m.re:", m.re)

print("m.pos:", m.pos)

print("m.endpos:", m.endpos)

print("m.lastindex:", m.lastindex)

print("m.lastgroup:", m.lastgroup)

print("m.group():", m.group())

print("m.group(1,2):", m.group(1,2))

print("m.groups():", m.groups())

print("m.groupdict():", m.groupdict())

print("m.start(2):", m.start(2))

print("m.span(2):", m.span(2))

print(r"m.expand(r'\g \g\g'):", m.expand(r'\2 \1\3'))

#search 不一定从第0位开始匹配

pattern = re.compile(r'world')

match = re.search(pattern, 'hello world!')

if match:

    print(match.group())

#split 已pattern分割字符串

pattern = re.compile(r'\d+')

print(re.split(pattern, 'one1two2three33four4'))

#findall 以列表形式返回全部能匹配的子串

pattern = re.compile(r'\d+')

print(re.findall(pattern, 'one1two2three33four4'))

#finditer 返回一个顺序访问每一个匹配结果的迭代器

pattern = re.compile(r'\d+')

for m in re.finditer(pattern, 'one1two2three3four4'):

    print(m.group())

#替换

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

s = 'i say, hello world!'

print(re.sub(pattern, r'\2 \1', s))

def func(m):

    return m.group(1).title() + ' ' + m.group(2).title()

print(re.sub(pattern, func, s))

#subn 比替换多返回了一个替换次数

print(re.subn(pattern, func, s))