Ruby RegEx
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Regular expressions allow matching and manipulation of textual data. They are commonly abbreviated as regex or regexp. Regular expressions in Ruby can be used to scan strings for patterns, replace parts of strings, and split strings based on matching separators. Regular expression syntax uses forward slashes to delimit patterns and backslashes to escape characters. Common regex constructs include character sets, quantifiers, word boundaries, and capturing groups. Methods like match, =~, scan, split, gsub can be used to apply regular expressions to strings in Ruby.
![They are escaped with a backward slash (\).Characters That Need to be Escaped. | ( ) [ ] { } + \ ^ $ * ?](https://image.slidesharecdn.com/regex-100803201744-phpapp01/85/Ruby-RegEx-6-320.jpg)
![Regex Basics[abc] A single character: a, b or c [^abc] Any single character but a, b, or c [a-z] Any single character in the range a-z [a-zA-Z] Any single character in the range a-z or A-Z ^ Start of line $ End of line \A Start of string \z End of string](https://image.slidesharecdn.com/regex-100803201744-phpapp01/85/Ruby-RegEx-7-320.jpg)
![Scan>> numbers = "one two three"=> "one two three">> numbers.scan(/\w+/)=> ["one", "two", "three”]](https://image.slidesharecdn.com/regex-100803201744-phpapp01/85/Ruby-RegEx-12-320.jpg)
![Split with Regular Expressions>> "one two\tthree".split(/\s/)=> ["one", ”two", "three"]](https://image.slidesharecdn.com/regex-100803201744-phpapp01/85/Ruby-RegEx-13-320.jpg)
Ruby RegEx
- 1. /regex will find me/Regular Expressions
- 2. What are Regular ExpressionsRegular expressions allow matching and manipulation of textual data.Abbreviated as regex or regexp, or alternatively, just patterns
- 3. Regular Expressions in Ruby
- 4. Using Regular Expressions Scan a string for multiple occurrences of a pattern.Replace part of a string with another string.Split a string based on a matching separator.
- 5. Regular Expression Syntax Regular expressions are put between two forward slashes (/match_me/)
- 6. They are escaped with a backward slash (\).Characters That Need to be Escaped. | ( ) [ ] { } + \ ^ $ * ?
- 7. Regex Basics[abc] A single character: a, b or c [^abc] Any single character but a, b, or c [a-z] Any single character in the range a-z [a-zA-Z] Any single character in the range a-z or A-Z ^ Start of line $ End of line \A Start of string \z End of string
- 8. Regex Basics cont.... Any single character \s Any whitespace character \S Any non-whitespace character \d Any digit \D Any non-digit \w Any word character (letter, number, underscore) \W Any non-word character \b Any word boundary character
- 9. Regex Basics cont...(...) Capture everything enclosed (a|b) a or b a? Zero or one of a a* Zero or more of a a+ One or more of a a{3} Exactly 3 of a a{3,} 3 or more of a a{3,6} Between 3 and 6 of a
- 10. Regex: .match>> category = "power tools"=> "power tools">> puts "on Sale" if category.match(/power tools/)on Sale>> puts "on Sale" if /power tools/.match(category)on Sale
- 11. Regex: =~>> category = "shoes"=> "shoes">> puts "15 % off" if category =~ /shoes/15 % off>> puts "15 % off" if /shoes/ =~ category15 % off>> /pants/ =~ category=> nil>> /shoes/ =~ category=> 0>> category = "women's shoes”>> /shoes/ =~ category=> 88th character
- 12. Scan>> numbers = "one two three"=> "one two three">> numbers.scan(/\w+/)=> ["one", "two", "three”]
- 13. Split with Regular Expressions>> "one two\tthree".split(/\s/)=> ["one", ”two", "three"]
- 15. gsub with a block"one two\tthree".gsub(/(\w+)/) do |w| puts wendonetwothree
- 16. Title CaseCapitalize All Words of a Sentence:>> full_name.gsub(/\b\w/){|s| s.upcase}=> "Yukihiro Matsumoto"
Editor's Notes
- #14: s finds spaces, tabs and new lines