User Guide

Using Regular Expressions 91
Special characters
Because special characters are the operators in regular expressions, in order to
represent a special character as an ordinary one, you need to precede it with a
backslash. To represent a backslash, for instance, use a double backslash (\\).
Single-character regular expressions
This section describes the rules for creating regular expressions. You can use regular
expressions in the Search > Extended Find and Replace command to match complex
string patterns.
The following rules govern one-character RegExp that match a single character:
• Special characters are: + * ? . [ ] ^ $ ( ) { } | \ &
• Any character that is not a special character matches itself.
• Use the keyboard (Tab, Enter) to match whitespace characters.
• The asterisk (*) matches the specified characters throughout the entire
document.
• The carat (^) matches the beginning of the document.
• The dollar sign ($) matches the end of the document.
• A backslash (\) followed by any special character matches the literal character
itself, that is, the backslash escapes the special character.
• The # and - characters must be escaped in expressions (## --) just as though they
were special characters.
• A period (.) matches any character, including a new line. To match any character
except a new line, use
[^#chr(13)##chr(10)#], which excludes the ASCII
carriage return and line feed codes.
• A set of characters enclosed in brackets ([]) is a one-character RE that matches
any of the characters in that set. For example,
[akm] matches an a, k, or m. Note
that if you want to include a closing square bracket (]) in square brackets, it must
be the first character. Otherwise, it does not work even if you use \].
• Any regular expression can be followed by one of the following suffixes:
− {m,n} forces a match of m through n (inclusive) occurrences of the preceding
regular expression
− {m,} forces a match of at least m occurrences of the preceding regular
expression
The syntax {,n} is not allowed.
• A range of characters can be indicated with a dash. For example,
[a-z] matches
any lowercase letter. However, if the first character of the set is the caret (^), the
RegExp matches any character except those in the set. It does not match the
empty string. For example,
[^akm] matches any character except a, k, or m. The
caret loses its special meaning if it is not the first character of the set.
• All regular expressions can be made case-insensitive by substituting individual
characters with character sets, for example,
[Nn][Ii][Cc][Kk].