A: Regular Expressions
【1】
(1) Definition: a string of well defined manner of operation of the string
(2) Function: Filter the data to match
【2】
(1) simulation scenarios: http://tool.chinaz.com/regex/
(2) string:
(1) Definition: a group of more characters may appear in the same location
(2) forms: []
(3) table to form groups of characters:
| expression | Matching character | result | explain |
| [0123456789] | 6 | True | 0-9 match any number |
| [0-9] | x | False | Matching digital non-alphabetic |
| [a-z] | x | True | Az matches all lowercase letters |
| [A-Z] | A | True | AZ matches all uppercase letters |