[PYTHON] Regular expression re

import re

"""
match()Determine if it matches the regular expression at the beginning of the string
search()Manipulate strings to find out where regular expressions match
findall()Find all substrings that match the regular expression and return them as a list
finditer()Returns a unique match object iterator
"""

# .Is any one character
#A match object is returned
m = re.match('a.c', 'abc')
# group()You can see the contents at.
print(m.group())

#A match object is returned
m = re.search('a.c', 'test abc test abc')
print(m)
print(m.span())
print(m.group())

m = re.findall('a.c', 'test abc test abc')
print(m)

#Match object iterator is returned
m = re.finditer('a.c', 'test abc test abc')
print([w.group() for w in m])

#Repeat 0 or 1
m = re.match('ab?', 'a')
print(m)
#Repeat 0 or more times
m = re.match('ab*', 'abb')
print(m)

#Repeat one or more times
m = re.match('ab+', 'abbb')
print(m)

#Repeat 3 times
m = re.match('a{3}', 'aaaa')
print(m)

# 2-Repeat 4 times
m = re.match('a{2,4}', 'aaaa')
print(m)

#Alphanumeric and underscore,[]The part of is called a set.
m = re.match('[a-zA-Z0-9_]', '1')
# m = re.match('\w', '1')
print(m)

#Other than alphanumeric characters and underscore
m = re.match('[^a-zA-Z0-9_]', '@')
# m = re.match('\W', '1')
print(m)

#Any number
m = re.match('[0-9]', '1')
# m = re.match('\d', '1')
print(m)

#Other than arbitrary numbers
m = re.match('[^0-9]', '@')
# m = re.match('\D', '1')
print(m)

#a or b
m = re.match('a|b', 'b')
print(m)

#Treat as a lump
m = re.match('(abc)+', 'abcabc')
print(m)

#space
m = re.match('\s', ' ')
print(m)

#Other than space
m = re.match('\S', '1')
print(m)

#escape
m = re.match('\*', '*')
print(m)
m = re.match('\?', '?')
print(m)

#First match
m = re.search('^abc', 'abctest abc')
print(m)
#end
m = re.search('abc$', 'test abc')
print(m)

Execution result:

abc
<re.Match object; span=(5, 8), match='abc'>
(5, 8)
abc
['abc', 'abc']
['abc', 'abc']
<re.Match object; span=(0, 1), match='a'>
<re.Match object; span=(0, 3), match='abb'>
<re.Match object; span=(0, 4), match='abbb'>
<re.Match object; span=(0, 3), match='aaa'>
<re.Match object; span=(0, 4), match='aaaa'>
<re.Match object; span=(0, 1), match='1'>
<re.Match object; span=(0, 1), match='@'>
<re.Match object; span=(0, 1), match='1'>
<re.Match object; span=(0, 1), match='@'>
<re.Match object; span=(0, 1), match='b'>
<re.Match object; span=(0, 6), match='abcabc'>
<re.Match object; span=(0, 1), match=' '>
<re.Match object; span=(0, 1), match='1'>
<re.Match object; span=(0, 1), match='*'>
<re.Match object; span=(0, 1), match='?'>
<re.Match object; span=(0, 3), match='abc'>
<re.Match object; span=(5, 8), match='abc'>

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