1. Add "/....../" to both sides of the delimiter and use "#......#"
2. Atoms visible Atoms & smallest units of invisible atoms
Visible atoms: Characters that can be seen with the naked eye
Invisible atoms: atoms that are invisible to the naked eye, such as: \ n line break \ t tab
Suggestion: In about Chinese characters to match, first go to Webmaster tools, the Chinese characters into Unicode encoding, in the match, you can avoid coding different errors produced.
3. Meta-Characters
How to filter atoms
| Match two or more branch selections.
[.......] Matches any one of the atoms in the square brackets
[^.......] Match any character except the atoms in square brackets, note: [^ These two symbols must be joined together.
The collection of atoms
. Matches any character except the line break. equivalent to [^\n]
\d matches a decimal number [0-9]
\d matches a non-decimal number [^0-9]
\s matches an invisible atom [\t\n\r\f\v]
\s matches any one visible atom [^\t\n\r\f\v]
\w matches any number, letter, underscore [0-9a-za-z_]
\w matches any one non-digit, letter, underscore [^0-9a-za-z_]
4. quantifiers not only support atoms, they also support the collection of atoms.
{n} The atom in front of it just appears n times
{n,} The atoms in front of it appear at least n times
{n,m} The atom in front of it appears at least n times, with a maximum of M times
* Match 0 times, 1 times, multiple {0,}
+ match 1 times, multiple {1,}
? Match 0 times, 1 times {0,1}
5. Border control
^ Must start with the next atom.
$ must end with the one atom before
() match the whole of which is an atom