Regular Expressions

You can perform advanced text pattern matching using regular expressions. Regular expressions provide more flexibility than simple wildcards in defining rules or views. To match an exact regular expression character, precede the character with a backslash (\). The following table lists regular expression operators and their definitions.

The following table provides examples of regular expressions and ilustrates cases where there is a match or there is not a match.

Menu Item Character Definition
Any Character . Matches any single character.
Character in Range [ ] Matches any single character from within the bracketed list. Within square brackets, most characters are interpreted literally.
Character Not in Range [^] Specifies a set of characters not to be matched.
Beginning of Line ^ Matches the beginning of a line.
End of Line $ Matches the end of a line.
Or | Matches either the regular expression preceding it or the regular expression following it.
Group ( ) Groups one or more regular expressions to establish a logical regular expression consisting of sub-regular expressions. Used to override the standard precedence of certain operators.
0 or 1 Matches ? Specifies that the preceding regular expression is matched 0 or 1 time.
0 or More Matches * Specifies that the preceding regular expression is matched 0 or more times.
1 or More Matches + Specifies that the preceding regular expression is matched 1 or more times.
Exactly nMatches {n} Specifies that the preceding regular expression is matched exactly nnumber of times.
At Least nMatches {n,} Specifies that the preceding regular expression is matched nor more times.
At Most nMatches {,n} Specifies that the preceding regular expression is matched nor fewer times.
nto mMatches {n,m} Specifies that the preceding regular expression is matched a maximum of ntimes and a minimum of mtimes. If not specified, mdefaults to 0.

If nis not specified, the default depends on whether the comma is present. If no comma is present, ndefaults to m. If a comma is present, ndefaults to a very large number.
New Line Character \n Matches a new line.
Tab Character \t Matches a tab character.
Example Matches Does Not Match
st.n Austin and Houston Webster
st[io]n Austin and Houston Stanton
st[^io]n Stanton Austin or Houston
^houston Houston South Houston or Fort Sam Houston
ston$ Houston and Galveston Stonewall
dall|hart Dallas and Dalhart and Lockhart Dale
dal(l|h)art Dalhart Dallas or Lockhart
il?e$ Etoile and Wylie Beeville
il*e$ Etoile and Wylie and Beeville Bellaire
il+e$ Etoile and Beeville Wylie
ad{2} Addison and Caddo Adkins
(la.*){2,} Highland Villiage and Lake Dallas Laredo
il{,1}e$ Bowie and Etoile Brownsville
(a.*){2,3} Alamo Heights and La Blanca Austin or Aransas Pass
not ville Houston and Dallas Brownsville