w, n, d =3D frac_str =3D~ %r{/} \

? frac_str.matc= h(%r{(?:(\S+) )*?(\S+)/(\S+)}).captures \

: [1, frac_str, 0]

I've use %r{} to quote regex, so no need to escape = for /

On= Thu, Dec 20, 2012 at 8:45 AM, Derrick B. <lists@ruby-forum.com>= wrote:

Hello all,

I am converting a Perl program to Ruby in order to learn Ruby. =A0There is<= br> an expression that takes a string, ("1 3/4" or "5", for= example)
determines what kind of fraction was entered, and assigns variables (w,
n, d), appropriately. =A0If a whole number was entered, then it assigns
the variables differently, of course.

The expression first checks for the presence of a slash ("/") to<= br> determine if it is a fraction or whole number. =A0Then, using the
conditional operator, assigns the variables, appropriately.

Here are the two expressions:

Perl:

=A0 =A0 my ($w, $n, $d) =3D ( $frac_str =3D~ /\// )
=A0 =A0 =A0 =A0 =A0 =A0 ? $frac_str =3D~ /(?:(\S+) )??(\S+)\/(\S+)/
=A0 =A0 =A0 =A0 =A0 =A0 : ( 1, $frac_str, 0 );

Ruby:

=A0 =A0 w, n, d =3D frac_str.match(/\//) \
=A0 =A0 =A0 =A0 ? frac_str.match(/(?:(\S+) )*?(\S+)\/(\S+)/).captures \
=A0 =A0 =A0 =A0 : 0, frac_str, 1
=A0 =A0 puts "w: #{w}, n: #{n}, d: #{d}" =A0# check assignment

I used irb to test the regex and it works just fine:

exp =3D Regexp.new(/(?:(\S+) )*?(\S+)\/(\S+)/)
=3D> /(?:(\S+) )*?(\S+)\/(\S+)/

str =3D "1 3/4"
=3D> "1 3/4"

n, w, d =3D str.match(exp).captures
=3D> ["1", "3", "4"]

w
=3D> "3"

n
=3D> "1"

d
=3D> "4"

But, the above version outputs:

w: 134, n: 1 3/4, d: 1

It appears to recurse over the regex and duplicate the captures. =A0But, since I am new to this language, I know I can use an 'if..else'
statement, but since I am coming from Perl, I figured that a similar
expression would "just work"! =A0:)

Thanks for your time and input,

Derrick

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Wei Feng

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