Matching number segments using regex

Creating classifications for numbers using only regex.

The below example can be used to segment time in milliseconds into appropriate time groupings;

\b(?:[0-9][0-9]?[0-9]?)\b      // < 1 second

\b(?:[1-2][0-9][0-9][0-9])\b   // 1-3 seconds

\b(?:[3-4][0-9][0-9][0-9])\b   // 3-5 seconds

\b(?:[1-9][0-9][0-9][0-9][0-9]*|[5-9][0-9][0-9])\d\b  // > 5 seconds

What the regex means:

• \b - Word boundary
• (?: - Non capturing group: groups multiple tokens together without creating a capture group.
• [0-9] - Character Set: we use one for each character we expect to see.
• ? - Quantfier: used to allow 0 or 1 or preceding tokens

• The basis for this regex is the following syntax, here matching the range 0-9

  \b[0-9]\b

• This can then be slowly build up to match your desired range. e.g. 1-100

  \b([0-9]|[1-9][0-9]|100)\b