Basic Learning of regular expression (1)

Today, we will record some basic knowledge about regulator for future use.
1. Some syntaxes to be remembered.
Character matching Syntax:
\ D matches the number '\ d' to 3, not C;

\ D match non-digit '\ d' match C, not match 3;

\ W matches any single character '\ W \ W' to match A3, not @ 3;

\ W match non-single character '\ W' match @, does not match C;

\ S matches blank characters '\ D \ s \ d' to match 3 D, not ABC;

\ S matches non-null characters '\ s \ s' to match a #4, not 3 D;

. Match any character '...' matches a $5, does not match line feed;

[…] Matching any character in the brackets [B-d] matches B, C, and D, but does not match E;

[^…] Match non-Parentheses [^ B-Z]: Match A. do not match B-Z;

Repeated matching Syntax:

{N} matched n characters \ D {3} matched \ D, not matched \ D or \ D

{N ,}match n times or more \ W {2} match \ W and \ W or above, not match \ W

{N, m} matches \ s, mismatch \ s

? Match 0 or 1 time 5? Match 5 or 0, not 5 or 0

+ Match one or more \ s + matches more than one \ s, and does not match more than one \ s

* Match 0 or more times \ W * match 0 or more \ W, not match non-N * \ W

Character locating Syntax:

^ Locate the start position of the subsequent mode

$ The front mode is at the end of the string

\ A Start position of the previous Mode

\ Z front mode end position

\ Z front mode end position (before line feed)

\ B matches a word boundary

\ B matches a non-word boundary

Escape matching Syntax:

"\" + Actual character \. * +? | () {}^ $ For example: \ matched character "\"

\ N match line feed

\ R match and press ENTER

\ T matches horizontal tabs

\ V matches vertical tabs

\ F match form feed

\ NNN matches an octal ASCII

\ Xnn matches a hexadecimal ASCII

\ Unnnn matches four hexadecimal uniode

\ C + uppercase letters match Ctrl-UPPERCASE letters, for example, \ CS-match Ctrl + S

The above are some regulator syntaxes that must be memorized.