Regular expression matching method

A note on how to match regular expressions in Python

2 Call the re.compile () function to create a Regex object (using a raw string). Example: phone_num_regex = re.compile (r'\ d \ d \ d- \ d \ d \ d- \ d \ d \ d \ d')

3 If you pass the string to be searched to the search () method of the Regex object, a Match object will be returned. Example: mo = phone_num_regex.search ('My phone number is 415-555-4242.') mo means Matching object

4 Call the group () method of the Match object to get the actual matched string. Example: print ('phone number found:' + mo.group ()) → Phone number found: 415-555-4242

Shortened form	meaning
\d	0~Number 9
\D	0~Other than the number 9
\w	Letters, numbers, underlining(Word word w)
\W	Other than letters, numbers and underscores
\s	Spaces, tabs, line breaks(Blank space s)
\S	Other than spaces, tabs and line breaks

+? Matches 0 or 1 occurrences of the previous group.

- Matches 0 or more occurrences of the previous group.
- Matches one or more occurrences of the previous group.
{n} matches n occurrences of the previous group.
{n,} matches n or more occurrences of the previous group.
{, m} matches 0 to m occurrences of the previous group.
{n, m} matches n ~ m occurrences of the previous group.
{n, m} ?, *?, +? Make a non-greedy match for the previous group.
^ spam matches strings starting with "spam".
spam $ matches strings ending in "spam". +. Matches any single character other than the newline character.
\ d, \ w, \ s match numbers, letters that make up words, and whitespace characters, respectively.
\ D, \ W, \ S match numbers, letters that make up words, and non-whitespace characters, respectively.
[abc] matches any single character in square brackets.
[^ abc] matches any single character except the square bracket character.