Ruby Method of the Month 2009.09. Lightning talk for the Columbus Ruby Brigade.

1. gsub
M e t h o d o f t h e M o n t h
Kevin Munc
@muncman

2. Global SUBstitutions
String#gsub(pattern, replacement)
String#gsub(pattern) { |match| block }

3. Global SUBstitutions
String#gsub(pattern, replacement)
String#gsub(pattern) { |match| block }
The ‘pattern’ can be a String or a Regexp.

4. seq = "0123456789"
=> "0123456789"
seq.gsub('no match',
'anything')
=> "0123456789"
seq.gsub('567', '___')
=> "01234___89"

5. seq.gsub('567', '_')
=> "01234_89"
seq.gsub('567', '.....')
=> "01234.....89"
seq.gsub('567','')
=> "0123489"

7. seq.gsub(/[5-9]/, 'g')
=> "01234ggggg"

8. seq.gsub(/[5-9]/, 'g')
=> "01234ggggg"
seq.sub(/[5-9]/, 'g')
=> "01234g6789"

9. Bang!
(like a gun shot in a
ghetto)
seq = "Matz Dave DHH Zed Why"
=> "Matz Dave DHH Zed Why"

10. Bang!
(like a gun shot in a
ghetto)
seq = "Matz Dave DHH Zed Why"
=> "Matz Dave DHH Zed Why"
seq.gsub!('Zed ','')
=> "Matz Dave DHH Why"
seq
=> "Matz Dave DHH Why"

11. With Blocks

12. With Blocks
“0123456789”.gsub(/d/) do |digit|
digit.to_i + 1
end
=> "12345678910"

13. With Blocks
“0123456789”.gsub(/d/) do |digit|
digit.to_i + 1
end
=> "12345678910"
“0123456789”.gsub(/d/) do |digit|
digit.to_i * 2
end
=> "024681012141618"

14. seq = "0123456789"
=> "0123456789"

15. seq = "0123456789"
=> "0123456789"
seq.gsub(/d/) do |digit|
(digit.to_i * 2).to_s + '-'
end
=> "0-2-4-6-8-10-12-14-16-18-"

16. seq = "0123456789"
=> "0123456789"

17. seq = "0123456789"
=> "0123456789"
seq.gsub(/d/) { |digit|
digit if (digit.to_i % 2 == 0)
}
=> "02468"

18. "COJUG".gsub(/[^C].*$/, 'RB')
=> "CRB"

20. "a1b2c3".gsub(/d/) do |x|
puts "#{x} cheers for CRB!"
end
1 cheers for CRB!
2 cheers for CRB!
3 cheers for CRB!
=> "abc"

21. Questions? Answers? Hungry?
Image Credits: http://www.flickr.com/photos/terry_wha/39869806/ - http://www.flickr.com/photos/bredgur/2740011432/ - http://travel.asianfanatics.net/images/3/35/MTR-Corporation-logo.png - http://www.asiaworld-expo.com/Images/en-US/
static/map/tran_mtrMap3_l.jpg - http://www.flickr.com/photos/32912172@N00/3143351169/ - http://www.vagaemprego.com.br/wp-content/uploads/2009/08/subway_logo_large1.jpg - http://www.flickr.com/photos/25035545@N04/2477315249/ -
http://www.flickr.com/photos/turtlemom_nancy/1393994488/ - http://www.flickr.com/photos/ben_pollard/2203650937/