The use of regular expressions

[] Table one character, [1-9] table appears 1-9 in any one character, is random

[^] table except for those characters, the rest can be

{} The number of times the rule appears, {1,5} indicates a minimum of 1 occurrences, up to 5 times

？ Table 0-1 Times

+ Table 1-At least one occurrence at any time

* Table 0-any time

(|) Represents grouping

Example

I need to specify that an input is a positive integer within 20000 and a multiple of 100

(200|1[0-9]{2}| [1-9] [1-9]?) 00 only a multiple of the input 100, no more than 20000, no letters, negative numbers, the space can be

If it is necessary to specify that the input character is a letter

([a-z]| [A-z]) Only one letter or a-Z between the input A-Z will be

The use of regular expressions