Hope someone can give me a supplement.
| character |
Function and Introduction |
| one, |
non-printing characters |
| \cx |
Matches the control character indicated by x. For example: \cM matches a Control-M or carriage return. The x value must be one of AZ or az, otherwise, c is treated as a literal "c" character |
| \f |
Matches a form feed character. Equivalent to \x0c and \cL |
| \n |
Matches a newline character. Equivalent to \x0a and \cJ |
| \r |
Matches a carriage return. Equivalent to \x0d and \cM |
| \s |
Matches any whitespace character, including spaces, tabs, form feeds, and so on. Equivalent to [\f\n\r\t\v]. Note that Unicode regular expressions will match full-width spaces |
| \S |
Matches any non-whitespace character. Equivalent to [^\f\n\r\t\v] |
| \t |
Matches a tab character. Equivalent to \x09 and \cl |
| \v |
Matches a vertical tab character. Equivalent to \x0b and \cK |
| two, |
Special characters |
| () |
Matches the start and end of a subexpression. |
| . |
Matches any single character except newline \n (must have a matching character). |
| [] |
Matches any one character that appears in square brackets . Such as: [bce] represents one of b, c, e. |
| \ |
Mark the next character as a special character, a literal character, a backreference, or an octal escape. For example, \\n matches \n, \n matches a newline character, \\ matches \ |
| {} |
Marks the start and end of a qualifier expression. |
| | |
Pipeline selection, indicating that one of the two options is selected. |
| \d |
Matches a numeric character. Equivalent to [0-9] |
| [0-9] |
matches any number. Equivalent to \d |
| \D |
Matches a non-numeric character. Equivalent to [^0-9] |
| [a-z] |
matches any lowercase letter |
| [A-Z] |
matches any uppercase letter |
| [a-zA-Z0-9] |
matches any letter and number |
| \w |
Matches any word character that contains an underscore. Equivalent to [A-Za-z0-9_] |
| \W |
Matches any non-word character. Equivalent to [^A-Za-z0-9_] |
| [\u4e00-\u9fa5] |
Match pure Chinese |
| three, |
locator |
| * |
Matches the preceding subexpression zero or more times |
| + |
Matches the preceding subexpression one or more times |
| ? |
Matches the preceding subexpression zero or one time, or specifies a non-greedy qualifier. By placing ? after the *, +, or ? qualifiers, the expression is converted from a "greedy" expression to a "non-greedy" expression or minimal match. |
| {n} |
n is a non-negative integer. Matches the preceding subexpression n times |
| {n,} |
n is a non-negative integer. Matches the preceding subexpression at least n times |
| {n,m} |
Both m and n are non-negative integers, where n≤m. Matches the preceding subexpression at least n and at most m times. Note that there can be no spaces between the comma and n, m |
| Four, |
qualifier |
| ^ |
The start position of the matching string, such as: ^h matches the beginning of h; when it is in the square bracket expression, it means that the character set is not accepted, for example [^0-9] matches characters other than numbers |
| $ |
match the end of the string |
| \b |
Matches a word boundary, that is, the position of a word and a space |
| \B |
Non-word boundary matching |
5. Modifier:
Modifier: i, the variable provided by the re module: re.I, makes the mode case-insensitive, that is, case-insensitive.
Modifier: m, the variable provided by the re module: re.M, so that the mode can have multiple line headers and line positions in multi-line text, affecting ^ and $.
Modifier: s, the variable provided by the re module: re.S, let the wildcard character . represent any character (including the newline character \n).