This is a more general answer for future viewers.
Regex in Dart works much like other languages. You use the RegExp class to define a matching pattern. Then use hasMatch() to test the pattern on a string.
Examples
Alphanumeric
final alphanumeric = RegExp(r'^[a-zA-Z0-9]+$');
alphanumeric.hasMatch('abc123'); // true
alphanumeric.hasMatch('abc123%'); // false
Hex colors
RegExp hexColor = RegExp(r'^#?([0-9a-fA-F]{3}|[0-9a-fA-F]{6})$');
hexColor.hasMatch('#3b5'); // true
hexColor.hasMatch('#FF7723'); // true
hexColor.hasMatch('#000000z'); // false
Extracting text
final myString = '25F8..25FF ; Common # Sm [8] UPPER LEFT TRIANGLE';
// find a variable length hex value at the beginning of the line
final regexp = RegExp(r'^[0-9a-fA-F]+');
// find the first match though you could also do `allMatches`
final match = regexp.firstMatch(myString);
// group(0) is the full matched text
// if your regex had groups (using parentheses) then you could get the
// text from them by using group(1), group(2), etc.
final matchedText = match?.group(0); // 25F8
There are some more examples here.
See also:
- Extracting text from a string with regex groups in Dart