From: Jim Menard <jimm@...>
Date: 2001-12-16T23:15:25+09:00
Subject: [ruby-talk:28677] Re: How do you do "character filtering" of a string using each_byte.

olczyk@interaccess.com (Thaddeus L. Olczyk) writes:

> I'm trying to do several things where I produce new strings from old
> strings by manipulating characters, and am stuck.
> As an example (please keep in mind this is an example and I am
> interested in the general technique ), consider a method which takes
> a string and produces a new string such that:
> 1) all digits are removed.
> 2) all lowercase are changed to uppercase.
> 3) multiple spaces are converted to one space
> 4) tab is converted to one space.

I'd use regulare expressions and String methods instead. For example,

    str = "abc 123    DeF\tghi"
    str.gsub!(/[0-9]/, '')		# Get rid of digits
    str.upcase!()			# Lower case to upper case
    str.gsub!(/[ \t]+/, ' ')		# Multiple spaces and tabs => ' '

    p str				# => "ABC DEF GHI"

The last line may not be exactly what you want. To implement (3) and (4)
exactly, you may want to do this instead

    str.gsub!(/  +/, ' ')		# There are two spaces before the '+'
    str.gsub!(/[\t]/, ' ')		# Tabs become single spaces

[snip]
>     string.each_byte{ |c| # aside: is it legal to pt the brace on the 
>                                      # next line?
[snip]

The brace, no. The |c|, yes.

Jim
-- 
Jim Menard, jimm@io.com, http://www.io.com/~jimm/
"Dvorak users of the world flgkd!" -- Kirsten Chevalier in rec.humor.oracle.d