045-001. using regular expressing, re.match(), re.search(), ^, $, |
@ # Regular expression is way to express string which has specific pattern # So, regular expression is used to search string in specific pattern, and to extract them, and to replace them with other pattern # And, regular expression is also used to check if some string follows specific rules @ # match() judges if entire "pattern" is contained in string or not re.match(pattern, string) import re # It judges if 'Hello, world!' contains 'Hello' re.match('Hello', 'Hello, world!') # <_sre.SRE_Match object; span=(0, 5), match='Hello'> # It judges if 'Hello, world!' contains 'Python' re.match('Python', 'Hello, world!') @ # search() judges if partial pattern is matched or not # Since 'Hello, world!' starts with Hello, pattern '^Hello' is matched with 'Hello, world!' re.search('^Hello', 'Hello, world!') # <_sre.SRE_Match object; span=(0, 5), match='Hello'> # Since 'Hello, world!' ends with world!, pattern 'world!$' is matched with 'Hello, world!' re.search('world!$', 'Hello, world!') # <_sre.SRE_Match object; span=(7, 13), match='world!'> @ # We can use | when using match() # There are hello or world in 'hello', pattern of 'hello|world' is matched with 'hello' re.match('hello|world', 'hello') # <_sre.SRE_Match object; span=(0, 5), match='hello'>