use part of the current match later in that match allows you to look for various forms of repetition. : Regexps Repetition « Development « Ruby






  1. Ruby
  2. Development
  3. Regexps Repetition

use part of the current match later in that match allows you to look for various forms of repetition.



def show_regexp(a, re) 
    if a =~ re 
        "#{$`}<<#{$&}>>#{$'}" 
    else 
        "no match" 
    end 
end 

# match duplicated letter 
show_regexp('He said "Hello"', /(\w)\1/) # He said "He<<ll>>o" 
# match duplicated substrings 
show_regexp('Mississippi', /(\w+)\1/)  # M<<ississ>>ippi








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6.You can also specify repetition within patterns.
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10.Match Perl, a space, and Python
11.Match Perl, zero or more spaces, and Python
12.Match Perl, one or more spaces, and Python
13.Match Perl, whitespace characters, then Python
14.Match Ruby, a space, and either Perl or Python
15.The match operator =~ can be used to match a string against a regular expression.
16.The part of a string matched by a regular expression can be replaced
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