Regex Range

Generates a Regular Expression that matches a range of numbers or characters.

Features

• Number ranges: range(1, 100)
• Negative to positive number ranges: range(-100, 100)
• Character ranges: range('A', 'Z')
• Case insensitive character ranges: range('a', 'Z')

Getting Started

dart pub add regex_range

And import the package:

import 'package:regex_range/regex_range.dart';

Usage

To generate a regex, you may use the range function to generate both number and character ranges, depending on what's passed in.

A number range is generated when passing numbers, and a character range is generated when passing strings of a single character.

Alternatively, you may use the numberRange and charRange functions to generate a number or character range, respectively.

Expression Pattern

You can get the generated expression pattern by using the pattern property of the RegExp object.

final regex = range(0, 255);

print(regex.pattern); // 25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9]

You may also use the exact parameter to generate an exact match, this will add ^ and $ to the expression to ensure it matches as a whole.

Number Range

final regex = range(-10, 10, exact: true);
// or
final regex = numberRange(-10, 10, exact: true);

print(regex.hasMatch('-5')); // true
print(regex.hasMatch('5')); // true
print(regex.hasMatch('11')); // false

Character Range

Case sensitivity is disabled when passing 2 characters with a different case. Case sensitivity can be set manually with the caseSensitive parameter in the charRange function.

final regex = range('b', 'Y', exact: true);
// or
final regex = charRange('B', 'Y', caseSensitive: false, exact: true);

print(regex.hasMatch('b')); // true
print(regex.hasMatch('Y')); // true
print(regex.hasMatch('Z')); // false

Generated Regex

The expressions below are not the exact expressions generated by the package, they are the simplified and equivalent.

Number Range

Range	Expression
0, 5	[0-5]
0, 10	[0-9]|10
25, 100	2[5-9]|[3-9][0-9]|100
-10, 10	-?[0-9]|-?10

Character Range

Range	Expression
A, Z	[A-Z]
a, z	[a-z]
a, Z	[a-zA-Z]
b, Y	[b-yB-Y]

Contributing

Contributions are welcome! Please open an issue or pull request if you find a bug or have a feature request.