Regular-Expression: Unterschied zwischen den Versionen

Version vom 15. Juni 2008, 07:01 Uhr

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Beschreibung

Reguläre Ausdrücke sind Muster, mit denen man den Aufbau von Zeichenketten beschreibt.

Characters

Ausdruck	Bedeutung
`x`	The character x
`\\`	The backslash character
`\0n`	The character with octal value 0n (0 <= n <= 7)
`\0nn`	The character with octal value 0nn (0 <= n <= 7)
`\0mnn`	The character with octal value 0mnn (0 <= m <= 3, 0 <= n <= 7)
`\xhh`	The character with hexadecimal value 0xhh
`\uhhhh`	The character with hexadecimal value 0xhhhh
`\t`	The tab character ('\u0009')
`\n`	The newline (line feed) character ('\u000A')
`\r`	The carriage-return character ('\u000D')
`\f`	The form-feed character ('\u000C')
`\a`	The alert (bell) character ('\u0007')
`\e`	The escape character ('\u001B')
`\cx`	The control character corresponding to x

Character classes

Ausdruck	Bedeutung
`xxx`	xxx
`xxx`	xxx

Predefined character classes

Ausdruck	Bedeutung
`xxx`	xxx
`xxx`	xxx

POSIX character classes (US-ASCII only)

Ausdruck	Bedeutung
`xxx`	xxx
`xxx`	xxx

Classes for Unicode blocks and categories

Ausdruck	Bedeutung
`xxx`	xxx
`xxx`	xxx

Boundary matchers

Ausdruck	Bedeutung
`xxx`	xxx
`xxx`	xxx

Greedy quantifiers

Ausdruck	Bedeutung
`xxx`	xxx
`xxx`	xxx

Reluctant quantifiers

Ausdruck	Bedeutung
`xxx`	xxx
`xxx`	xxx

Possessive quantifiers

Ausdruck	Bedeutung
`xxx`	xxx
`xxx`	xxx

Logical operators

Ausdruck	Bedeutung
`xxx`	xxx
`xxx`	xxx

Back references

Ausdruck	Bedeutung
`xxx`	xxx
`xxx`	xxx

Quotation

Ausdruck	Bedeutung
`\`	Nothing, but quotes the following character
`\Q`	Nothing, but quotes all characters until \E
`\E`	Nothing, but ends quoting started by \Q

Special constructs (non-capturing)

Ausdruck	Bedeutung
`(?:X)`	X, as a non-capturing group
`(?idmsux-idmsux)`	Nothing, but turns match flags on - off
`(?idmsux-idmsux:X)`	X, as a non-capturing group with the given flags on - off
`(?=X)`	X, via zero-width positive lookahead
`(?!X)`	X, via zero-width negative lookahead
`(?<=X)`	X, via zero-width negative lookahead
`(?>X)`	X, as an independent, non-capturing group

Embedded flag expressions

Ausdruck	Bedeutung
`(?u)`	Pattern.UNICODE_CASE
`(?s)`	Pattern.DOTALL
`(?m)`	Pattern.MULTILINE
`(?i)`	Pattern.CASE_INSENSITIVE
`(?x)`	Pattern.COMMENTS
`(?d)`	Pattern.UNIX_LINES
`---`	Pattern.CANON_EQ (not available)

@@ Zeile 183: / Zeile 183: @@
 ! Ausdruck || Bedeutung
 |-
-| <code>xxx</code>
+| <code>\</code>
-| xxx
+| Nothing, but quotes the following character
 |-
-| <code>xxx</code>
+| <code>\Q</code>
-| xxx
+| Nothing, but quotes all characters until \E
+|-
+| <code>\E</code>
+| Nothing, but ends quoting started by \Q
 |}
@@ Zeile 195: / Zeile 198: @@
 ! Ausdruck || Bedeutung
 |-
-| <code>xxx</code>
+| <code>(?:X)</code>
-| xxx
+| X, as a non-capturing group
+|-
+| <code>(?idmsux-idmsux)</code>
+| Nothing, but turns match flags on - off
+|-
+| <code>(?idmsux-idmsux:X)</code>
+| X, as a non-capturing group with the given flags on - off
+|-
+| <code>(?=X)</code>
+| X, via zero-width positive lookahead
+|-
+| <code>(?!X)</code>
+| X, via zero-width negative lookahead
+|-
+| <code>(?<=X)</code>
+| X, via zero-width negative lookahead
 |-
-| <code>xxx</code>
+| <code>(?>X)</code>
-| xxx
+| X, as an independent, non-capturing group
 |}