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Regular Expressions | ||
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.... Yet to be finished ....
Elements in regular expressionsy
A character that has no special meaning (such as for example y) is matched against itself
.
A dot matches any character, except new lines.
*
0 repetitions means that the previous element doesn't exist!
+
So, \+ is like a *, except that a * matches also if the previous element doesn't occur.
?
0 repetitions means that the previous element doesn't exist!
{n}{n,m}{,m}{n,}(regular-expressions)
A regular expression group.
Back references refer to regular expression groups.
\s
Whitespace characters (tabulator, space, newline?)
\S
Opposite of \s.
\d
Matches a digits. equivalent to [0123456789] or [0-9].
\D
Opposite of \d. equivalent to [^0-9].
\x
Matches a hex digit, equivalent to [0-9A-Fa-f].
\X
Opposite of \X.
\o
Matches an octal digit, equivalent to [0-7].
\O
Opposite of \o.
\w
Matches a word character, equivalent to [0-9A-Za-z].
\W
Opposite of \w.
\h
Head of word character (vim only?)
\H
Opposite of \h.
\a
Matches an alphabetic character, equivalent to [A-Za-z].
\A
Opposite of \a
\l
Lowercase character, equivalent to [a-z].
\L
Opposite of \l
\u
Uppercase letter, equivalent to [A-Z].
\U
Opposite of \u.
^
Matches the start of a line.
$
Matches the end of a line.
[abcd]
Matches one character that is between [ and ]. So [abcd] matches either a, b, c or d.
[^abcd]
Matches one character that is not between [ and ]. So [^abcd] matches neither a nor b nor c nor d. But it matches A, e, ...
regular-expression-1|regular-expression-2
Matches either regular-expression-1 or regular-expression-2
[[:META:]]
META can be:
It can be combined like so:
[[:digit:]a-f]
That would match hexa decimal representations of numbers.
\n
\n: a number. Matches the nth regular expression group.
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