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71 lines
1.3 KiB
Perl
71 lines
1.3 KiB
Perl
#Square brackets ([ and ]) delimits a range of characters.!
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[aA] means either a or A.
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[a-z] matches any lowercase character.
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[0-9] matches any digit.
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[0-9a-zA-Z] for characters commonly used in variable names.
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You can combine the brackets with other patterns.
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Pattern Interpretation
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/[aA]/ Matches against a or A.
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/[aA]+/ Matches one or more instances of a or A.
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/[aA]*/ Matches zero or more instances of a or A.
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/[aA]?/ Matches zero or one instance of a or A.
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/[^aA]/ Returns true if any character is found that is not a or A.
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/[aA]|[bB]/ Matches an instance of a or A or b or B; redundant in this case, as it is the same as /[aAbB]/.
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#The [] special characters enable you to define patterns that match one of a group of alternatives.!
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For example, the following pattern matches def or dEf:
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/d[eE]f/
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#Combine [] with + to match a sequence of characters of any length.!
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/d[eE]+f/
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This matches all of the following:
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def
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dEf
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deef
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dEef
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dEEEeeeEef
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#The bracketed character class!
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while(<DATA>){
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print if /[A-Za-z0-9_]/;
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}
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__DATA__
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Tom 101
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Jack 201
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Nart 301
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