From: Eric Hodel <drbrain@...7.net>
Date: 2003-10-15T16:26:17-07:00
Subject: Re: General Ruby Programming questions


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Florian Gross (flgr@ccan.de) wrote:

> Simon Kitching wrote:
>
> >(b) changing "require" searchpath
> >The $: variable holds the path used to locate files when the "require"
> >command is used. However this variable is read-only. In Perl, it is
> >possible to modify the equivalent path; can this be done in ruby?
>=20
> It might be read-only, but that doesn't mean that you can't change the=20
> object which it refers to:
>=20
> irb(main):002:0> $:.push('new')
> =3D> [..., 'new']

You really want to unshift here, the Array is read front to back, so new
libs that override base libs won't get require'd.

> >(d) iterating in reverse=20
> >I have an Array object, and wish to iterate over its members in reverse.
> >I would prefer not to have to create a new Array object in order to do
> >this iteration. Is there any way other than writing
>=20
> irb(main):004:0> [1, 2, 3].reverse_each { |item| puts item }
> 3
> 2
> 1

You can also use reverse.  An Array is smart, reverse takes constant time.

[1,2,3].reverse.map do |i| i * 2 end

--=20
Eric Hodel - drbrain@segment7.net - http://segment7.net
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