Theocacao: Regex Replacement in Ruby

Regex Replacement in Ruby

I'm stumped at to why Ruby's gsub() method works the way it does. Take a look at this following snippet.

(Update: I grabbed the pattern directly from the Pragmatic Rails book, not realizing it was a typo.)

value1 = "3 3 393923 2932--3 2939"

value2 = value1.clone

value3 = value1.clone



value1.gsub!(/[\w]/, '')  

puts "'#{value1}'"



value2.gsub!(/[^\w]/, '')

puts "'#{value2}'"



value3.gsub!(/[^\d]/, '')

puts "'#{value3}'"

The result is this:

'   -- '

'33393923293232939'

'33393923293232939'

I would have really expected the first one would work, as I'd be describing the pattern that I want to replace. Instead, for it seems that I have to negate the whitespace that I want to replace. Also, why is it that hyphens are considered whitespace?

Regex Replacement in Ruby
Posted Oct 30, 2005 — 3 comments below

Elliott Hughes — Oct 30, 05 481

\w means "word", not whitespace. you meant \s.

Scott Stevenson — Oct 30, 05 482

Doh. You're right. I grabbed the pattern from the Pragmatic Rails book (page 276), but I should have realized it was wrong anyway.

Pancho — Nov 09, 05 527

Ruby SUX anyway... Lets do asma!

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