| 1 |
For single characters, alternates can be specified by square brackets with
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[abc] meaning a or b or c
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| 2 |
For general strings one can use | to represent alternatives or so that above example can also be written
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a|b|c means a or b or c but this operator can be generalized to longer sequences so that 1995 CPS616 (first year this course was taught!) instructor can be written
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Fox|Furmanski or if we can't spell Polish names
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Fox|Furmansk(i|y|ie) # See later for use of parentheses
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| 3 |
Patterns can be Anchored in four ways:
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/^Keyname:/ matches to Keyname: ONLY if it starts string -- ^ only has this special meaning at start of regular expression
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/Quit$/ matches Quit ONLY if it ends string -- $ only has this meaning if at end of regular expression
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\b matches a word(PERL/C variable) boundary so that
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/Variable\b/ matches Variable but not Variables ( inside [] construct, \b means a backspace as described in earlier table)
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\B matches NOT a word boundary so that
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/Variable\B/ matches Variables but not Variable
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