Regex Regular Expression Learning notes

A practical example

1  Public Static voidMain (string[] args) {2         //Simple Practice3System.out.println (" -123". Matches ("-?\\d+")));4System.out.println ("+5678". Matches ("(-|\\+)? \\d+"));5         //QQ Number6System.out.println ("174678839431". Matches ("\\d{5,12}"));7         8         //Fixed phone number9System.out.println ("010 88886666". Matches ("\ \ 0\\d{2}[)-]?\\d{8}"));TenSystem.out.println ("010-88886666". Matches ("\ \ 0\\d{2}[)-]?\\d{8}")); OneSystem.out.println ("(010) 88886666". Matches ("\ (? 0\\d{2}[)-]?\\d{8}")); A          -         //number or letter (length limit 8-12) -System.out.println ("zhengbin123". Matches ("^[a-za-z0-9]{8,12}$"))); the          -         //rule-compliant IP address -System.out.println ("8.8.8.256". Matches ("(2[0-4]\\d|25[0-5]|[ 01]?\\d\\d?).) {3} (2[0-4]\\d|25[0-5]| [01]?\\d\\d?])); -          +         //only Chinese characters can be entered -System.out.println ("Man-Mo in Zhengzhou". Matches ("^[^\\w^[email protected]#$%^&* () {}\\\\|~ ',./';:; ',. , ~! ("") "<> ']{2,4}$")); +}

Ii. Expression Usage Rules table

Character

B	Specify character B
\xhh	Characters with a hexadecimal value of oxhh
\uhhhh	Hexadecimal representation of Unicode characters as Oxhhhh
\ t	TAB tab
\ n	Line break
\ r	Enter
\f	Page change
\e	Escaping (Escape)

Character class

.	Any character
[ABC]	Any character that contains a, B, and C (same as A|b|c)
[^ABC]	Any character except A, B, and C (negation)
[A-za-z]	Any character (range) from A to Z or from A to Z
[Abc[hij]]	Any A, B, C, H, I, and J characters (same as A|B|C|H|I|J) (consolidated)
[A-z&&[hij]]	Any h, I or J (cross)
\s	Whitespace (Space, tab, line feed, page feed, and carriage return)
\s	Non-whitespace character ([^\s])
\d	Number [0-9]
\d	Non-digital [^0-9]
\w	Word character [a-za-z0-9]
\w	Non-word character [^\w]

logical operators

Xy	Y followed by X.
X| Y	X or Y
X	Capture Group. I and capturing groups can be referenced in expressions using \i

Boundary Match character

^	Start of a row
$	End of Line
\b	The boundary of the word
\b	The boundaries of non-words
\g	The end of the previous match

Third, attention

Insert a normal backslash in Java, which should be ' \\\\ '

The ' \* ' in the table above is ' \\* ' in Java

Regex Regular Expression Learning notes