这是一个免费工具，用于根据给定的正则表达式验证给定的输入字符串，并根据定义的正则表达式匹配输出。
此工具支持：a) 全局搜索，b) 不区分大小写的搜索，c) 多行搜索
Following are the explanations for the flags used.
| Regex Parser Flags | Description |
|---|---|
| g (Global) | Don't return after the first match |
| s (Dot All) | Dot also matches newline |
| i (Case Insensitive) | Case insensitive match, ignores case of alphabets |
| m (Multiline) | Causes ^ and $ to match the begin/end of each line |
| D (Dollar) | Makes the dollar sign '$', to always match the end of the string, instead of end of the line |
| x (Extended) | Spaces in the pattern are ignored |
| U (Ungreedy) | The match becomes lazy by default |
Following are few example input regex and results for the sample input string
| InputRegex | Description | Input string | Result |
|---|---|---|---|
| [A-Z] | Character class: Literally matches all characters given inside '[' ']' | Once upon A time There was a King with Seven sons | |
| [A-Za-z]+ | Checks for one or more matches | Once upon A time | |
| ([A-Z]) | Capturing group: Captures the matches of pattern within '(' and ')' in separate groups | Once upon A time | |
| \w | Matches any word character (similar to [a-zA-Z0-9_]) | Site | |
| ([A-Z])\w+ | Capture all groups starting with uppercase alphabet and match all words starting with upper case alphabet followed by word character | Once |