Question

Let say I have this string: a = "Vallås centrum HALMSTAD"
And I would like to remove all lowercase, whitespace and the first uppercase letter so I only have a string with a => "HALMSTAD"

I tried something like this:

a = "Vallås centrum HALMSTAD"
b = a.gsub(/[:lower:]/, "")
puts b

But I get this output: a => "Vaås cntum HALMSTAD"

any ideas on how to to do this?

Answer 1

Try this:

a = "Vallås centrum ISN'T blah Blah HALMSTAD AND "
b = a.gsub(/\b[A-Z]?[^A-Z\s']+\s*\b/, '')
puts b

This should take care of most lower case words but you need to deal with other possible cases where you have punctuation symbols, question marks, exclamation marks, non-ASCII characters, etc…

You can fiddle with this here

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In view of @TimPietzcker’s comment of non-ASCII characters, you could replace the A-Z with the POSIX bracket expression [[:upper:]]

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UPDATE:
This would be a more complete solution:

Regex to find most lowercase words (This can still be extended for more symbols):

\b(?:[^\s]?[[:lower:]][^\s]?)+\s*\b[?!]?

Test the regex here

Ruby Code:

a = "Vallås centrum ISN'T blah Blah HALMSTAD AND BlaG and bLag's? FINISH "
b = a.gsub(/\b(?:[^\s]?[[:lower:]][^\s]?)+\s*\b[?!]?/, '')
puts b

Fiddle with the code here