Regular expressions were first developed from the Perl language and are
commonly used in the java.util.regex package (back):
Pattern class use: (matches() method)
1. Character matching [single character]: indicates the composition of any character
\ \: means'\', \n line break, \t tab
2. [Quantity: single] character set (you can choose one character from it)
[abc]: means any one of the characters a, b, c
[^ abc]: means that it is not any of the characters a, b, c
[a-zA-Z]: means that it is composed of any letter, not case sensitive
[0-9]: means any one of the numbers
3. [Quantity: Single ]: Simplified character set:.
(Dot): represents any character
\d: equivalent to the range of "[0-9]"
\D: equivalent to the range of [^0-9]
\s: matches any one Space, may be spaces, newlines, tabs
\S: match any non-space data
\w: match letters, numbers, underscores, equivalent to [a-zA-Z_0-9]
\W:[^a-zA-Z_0-9]
4. Boundary matching:
^: the beginning of the matching boundary
$: the end of the matching boundary
5. Quantity expression, by default, multi-character
expressions can be matched only if the quantity unit is added ? : The regular can appear 0 or 1 time
expression*: The regular can appear 0, 1 time] or multiple times
Expression+: The regular can appear 1 or more times
Expression {n}: The length of the expression Exactly n times
expression {n,}: the length of the expression is more than n times
Expression {n,m}: the length of the expression is n~m times
6. Logical expression: multiple regular
expressions can be connected X Expression Y: X expression is followed by expression Y
expression X|expression Y: only one expression is satisfied
(expression): set an overall description for the expression, you can set the quantity unit for the overall description
Regularly labeled study notes
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Origin blog.csdn.net/qq_41663470/article/details/113739698
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