regular expression

Metacharacters

effect

*

The previous character matches 0 Times or any number of times

.

Match any character except newline

^

Match the beginning of the line . for example ：^hello Will match to hello Beginning line

$

Match the end of the line . for example ：hello& Will match to hello Line ending with

[]

Matches any character specified in brackets , Match only one character .

for example ：[aoeiu] Match any vowel ,[0-9] Match any digit ,[a-z][0-9] Match two characters consisting of lowercase letters and one digit .

[^]

Match any character except the character in bracket . for example ：[^0-9] Match any non numeric character ,[^a-z] Any non lowercase letter .

\

Escape character . Used to cancel the meaning of special symbols .

\{n\}

Indicates that the character preceding it happens to appear n Time . for example ：[0-9]\{4\} matching 4 Digit number ,[1][3-8][0-9]\{9\} Match cell phone number .

\{n,\}

Indicates that the character before it is not less than n Time . for example ：[0-9]\{2,\} Two or more digits

\{n,m\}

Indicates that the character preceding it appears at least n Time , Most appear m Time . for example ：[a-z]\{6,8\} matching 6 To 8 The lower case letter of bit .