>>> pattern = re.compile(r'([a-z]+) ([a-z]+)', re.I)

>>> pattern.match("Hello World Wide Web")

<re.Match object; span=(0, 11), match='Hello World'>

>>> pattern1 = re.compile(r'([a-z]+)', re.I)

>>> pattern1.match("Hello World Wide Web")

<re.Match object; span=(0, 5), match='Hello'>

>>> pattern.match("Hello World Wide Web").group()

'Hello World'

>>> pattern.match("Hello World Wide Web").group(0)

'Hello World'

>>> pattern.match("Hello World Wide Web").group(1)

'Hello'

>>> pattern.match("Hello World Wide Web").group(2)

'World'

>>> pattern.match("Hello World Wide Web").group(3)

Traceback (most recent call last):

  File "<pyshell#11>", line 1, in <module>

    pattern.match("Hello World Wide Web").group(3)

IndexError: no such group

>>> 

程序：

import re

pattern = re.compile(r'([a-z]+) ([a-z]+)', re.I)

aa=pattern.match("Hello World Wide Web")

print(aa)

print(len(str(aa)))

print(aa.group())

print(aa.span(0))

print(type(aa.span(0)))

print(len(aa.span(0)))

pattern1 = re.compile(r'([a-z]+)', re.I)

aaa=pattern1.match("Hello World Wide Web")

print(aaa)

print(len(str(aaa)))

print(aaa.group())

print(aaa.span(0))

print(type(aaa.span(0)))

结果：

<re.Match object; span=(0, 11), match='Hello World'>

52

Hello World

(0, 11)

<class 'tuple'>

2

<re.Match object; span=(0, 5), match='Hello'>

45

Hello

(0, 5)

<class 'tuple'>

>>>