| Character
| Description
|
\
| Marks
the next
character as either a special
character or a literal. For example, "n" matches the character "n".
"\n" matches a newline character. The sequence "\\" matches "\" and
"\(" matches "(". |
| ^
|
Matches the
beginning of input.
|
$
| Matches
the end of
input. |
*
| Matches
the preceding
character zero or more times.
For example, "zo*" matches either "z" or "zoo". |
+
| Matches
the preceding
character one or more times.
For example, "zo+" matches "zoo" but not "z". |
?
| Matches
the preceding
character zero or one time.
For example, "a?ve?" matches the "ve" in "never".
|
.
| Matches
any single
character except a newline
character. |
| (pattern )
| Matches pattern
and remembers
the match. The matched substring can be retrieved from the resulting Matches
collection, using Item [0]...[n]. To match
parentheses characters ( ), use "\(" or "\)". |
x|y
| Matches
either x
or y.
For example, "z|wood" matches "z" or "wood". "(z|w)oo" matches "zoo" or
"wood". |
| {n}
| n
is a nonnegative integer. Matches exactly n times.
For example, "o{2}" does not match the "o" in "Bob," but matches the
first two o's in "foooood". |
{n,}
| n is
a nonnegative integer.
Matches at least n times. For example, "o{2,}" does
not match the "o" in "Bob" and matches all the o's in "foooood."
"o{1,}" is equivalent to "o+". "o{0,}" is equivalent to "o*".
|
{n,m}
| m
and n are
nonnegative integers. Matches at least n and at
most m times. For example, "o{1,3}" matches the
first three o's in "fooooood." "o{0,1}" is equivalent to "o?".
|
[xyz]
| A character set.
Matches any one of the enclosed
characters. For example, "[abc]" matches the "a" in "plain".
|
[^xyz]
| A negative character
set. Matches any character not
enclosed. For example, "[^abc]" matches the "p" in "plain".
|
[a-z]
| A range of characters.
Matches any character in the
specified range. For example, "[a-z]" matches any lowercase alphabetic
character in the range "a" through "z". |
[^m-z]
| A negative range
characters. Matches any character
not in the specified range. For example, "[m-z]" matches any character
not in the range "m" through "z". |
\b
| Matches
a word
boundary, that is, the position
between a word and a space. For example, "er\b" matches the "er" in
"never" but not the "er" in "verb". |
\B
| Matches
a non-word
boundary. "ea*r\B" matches the
"ear" in "never early". |
\d
| Matches
a digit
character. Equivalent to [0-9].
|
\D
| Matches
a
non-digit character. Equivalent to
[^0-9]. |
| \f
|
Matches
a form-feed character. |
\n
| Matches
a newline
character.
|
\r
| Matches
a carriage
return character.
|
\s
| Matches
any white
space including space, tab,
form-feed, etc.
Equivalent to "[ \f\n\r\t\v]".
|
\S
| Matches
any
nonwhite space character.
Equivalent to
"[^ \f\n\r\t\v]". |
| \t
|
Matches
a tab character. |
| \v
|
Matches
a vertical tab character. |
\w
| Matches
any word
character including underscore.
Equivalent to "[A-Za-z0-9_]". |
\W
| Matches
any
non-word character.
Equivalent to
"[^A-Za-z0-9_]". |
| \num
|
Matches num,
where num
is a positive integer. A reference back to remembered matches. For
example, "(.)\1" matches two consecutive identical characters.
|
\n
| Matches
n, where n is an octal escape
value. Octal escape values must be 1, 2, or 3 digits long. For example,
"\11" and "\011" both match a tab character. "\0011" is the equivalent
of "\001" & "1". Octal escape values must not exceed 256. If
they do, only the first two digits comprise the expression. Allows
ASCII codes to be used in regular expressions. |
\xn
| Matches
n,
where n
is a hexadecimal escape value. Hexadecimal escape values must be
exactly two digits long. For example, "\x41" matches "A". "\x041" is
equivalent to "\x04" & "1". Allows ASCII codes to be used in
regular expressions. |
