Regular Expression Tester
Anytime I use regular expressions (aka "regex"), I find myself doing a bit of trial-and-error until I get the right pattern. So, I whipped up this simple utility to help.
The tool will tell you where, if any, the patten is matched in your string by replacing any matching parts with [!MATCH!], and will point out parenthesized substrings.
If you're new to regexes, a good book to check out is Mastering Regular Expressions.
Helpful Hints
| ^ | Start of String |
| $ | End of string |
| \ | Escape the next character; interpret it literally |
| n* | Zero or more of 'n' |
| n+ | One or more of 'n' |
| n? | A possible 'n' |
| n | Exactly two of 'n' |
| n | At least 2 or more of 'n' |
| n | From 2 to 4 of 'n' |
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| () | Parenthesis to group substrings |
| (n|a) | Either 'n' or 'a' |
| . | Any single character |
| [1-6] | A number between 1 and 6 |
| [c-h] | A lower case character between c and h |
| [D-M] | An upper case character between D and M |
| [^a-z] | Absence of lower case a to z |
| [_a-zA-Z] | An underscore or any letter of the alpha |
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