Lecture3

There is 0 or 1 of the preceding element there is 0 or

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Unformatted text preview: A range of character \ Turn on/off the special meaning of a character RE: Pre- defined Paberns Class Meaning Class Meaning [:alnum:] Alphanumeric characters [:lower:] Lowercase characters [:alpha:] Alphabetic characters [:print:] Printable characters [:blank:] Space and tab characters [:punct:] Punctuation characters [:cntrl:] Control characters [:space:] Whitespace characters [:digit:] Numeric characters [:upper:] Uppercase characters [:graph:] Nonspace characters [:xdigit:] Hexadecimal digits NOTE: use [[:alpha:]] RE: Qualifier Character Meaning ? There is 0 or 1 of the preceding element * There is 0 or more of the preceding element + There is 1 or more of the preceding element \{n\} There is n of the preceding element \{n,m\} There is x of the preceding element, where n<=x<=m Examples •  What do the following paberns stand for? –  [a- zA- Z].* –  [abc]\{10\} –  [[:alpha:]] –  ABC, ^ABC, ^ABC$ •...
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