| Characters to Be Matched | Regular Expression |
|---|---|
| VOLTS | VOLTS |
| All uppercase and lowercase versions of volts, that is, VOLTS, Volts, volts, and so on | [Vv][Oo][Ll][Tt][Ss] |
| A space, a plus sign, or a minus sign | [ +-] |
| A sequence of one or more digits | [0-9]+ |
| Zero or more Spaces | \s* or * (that is, a space followed by an asterisk) |
| One or more Spaces, Tabs, Newlines, or Carriage Returns | [\t \r \n \s]+ |
| One or more characters other than digits | [~0-9]+ |
| The word Level only if it begins at the offset position in the string | ^Level |
| The word Volts only if it appears at the end of the string | Volts$ |
| The longest string within parentheses | (.*) |
| The longest string within parentheses but not containing any parentheses within it | ([~( )]*) |
| The character [ | [ [ ] |