How can ruby do this task (Case-insensitive string search & replace in Ruby)?

Question

I have some problem with replace string in Ruby.

My Original string : What the human does is not like what animal does.

I want to replace to: ==What== the human does is not like ==what== animal does.

I face the problem of case sensitive when using gsub. (eg. What , what) I want to keep original text.

any solution?

A better title might be, "Case-insensitive string search & replace in Ruby". Changing the title to something like that might help you get more people looking at your question. — donut, Nov 19 '09 at 09:40

score 21 · Accepted Answer · answered Nov 19 '09 at 09:49

21

If I understood you correctly this is what you want to do:

puts "What the human does is not like what animal does.".gsub(/(what)/i, '==\1==')

which will output

==What== the human does is not like ==what== animal does.

answered Nov 19 '09 at 09:49

hallski

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Updated example using the case insensitive flag to the regexp as was suggested by brianegge. – hallski Nov 19 '09 at 09:54

score 3 · Answer 2 · answered Nov 19 '09 at 09:59

3

another version without brackets () in regex,

puts "What the human does is not like what animal does.".gsub(/what/i,'==\0==')

==What== the human does is not like ==what== animal does.

answered Nov 19 '09 at 09:59

YOU

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score 3 · Answer 3 · answered Nov 19 '09 at 10:46

The important thing to take account of in all 3 answers so far, is the use of the "i" modifier on the regular expression. This is the shorthand way to specify the use of the Regexp::IGNORECASE option.

A useful Ruby Regexp tutorial is here and the class is documented here

score 2 · Answer 4 · edited May 23 '17 at 10:30

2

Use the block form of gsub.

"What the human does is not like what animal does.".gsub(/(what)/i) { |s| "==#{s}==" }
=> "==What== the human does is not like ==what== animal does."

edited May 23 '17 at 10:30

Community

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answered Nov 19 '09 at 09:50

brianegge

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I was writing the exact same thing. Here's the gsub documentation: http://ruby-doc.org/core/classes/String.html#M000817 – Yoann Le Touche Nov 19 '09 at 09:54

How can ruby do this task (Case-insensitive string search & replace in Ruby)?

4 Answers4