Regular expressions
Javascript form to interactively test regular expressions agains multiple text fragments.
Basic regular expression elements:
| Literals | |
| a B G 7 0 @ - = % | letters and digits match exactly |
| \. \\ \$ \[ | escaped special characters |
| \n \r \t \dec_code \xhex_code | non printable characters |
| Anchors | |
| ^ $ | begin/end of line |
| \b | word boundary |
| \B | not a word boundary |
| Character groups | |
| . | any char except newline |
| \d \D \s \S \w | decimal digit, non digit, whitespace, not whitespace, char from [a-zA-Z0-9_] |
| [char_list] | any char from list, i.e. [0123456789], [a-zA-Z0-9_] |
| [^char_list] | any char outside list, i.e. [^0-9] |
| Counts - add ? for non-greedy. | |
| expr* | 0 or more |
| expr? | 0 or 1 |
| expr+ | 1 or more |
| expr{n,m} | n to m |
| expr{n} | exactly n |
| expr{n,} | n or more |
| Alternation: expr1|expr2 | |