[#20675] RCR: non-bang equivalent to []= — Tobias Reif <tobiasreif@...>

Hi,

49 messages 2001/09/01
[#20774] Re: RCR: non-bang equivalent to []= — Tobias Reif <tobiasreif@...> 2001/09/03

I wrote:

[#20778] Re: RCR: non-bang equivalent to []= — Kevin Smith <kevinbsmith@...> 2001/09/03

--- Tobias Reif <tobiasreif@pinkjuice.com> wrote:

[#20715] oreilly buch von matz - website online — markus jais <info@...>

hi

43 messages 2001/09/02
[#20717] Re: OReilly Ruby book has snail on cover — ptkwt@...1.aracnet.com (Phil Tomson) 2001/09/02

Actually, thanks for posting it here. I was trying to search OReilly's

[#20922] Re: OReilly Ruby book has snail on cover — Paul Brannan <pbrannan@...> 2001/09/05

On Mon, 3 Sep 2001, Phil Tomson wrote:

[#20768] Minor cgi.rb question — "Hal E. Fulton" <hal9000@...>

I don't have much experience with

25 messages 2001/09/03

[#20770] Calling member methods from C++ — jglueck@... (Bernhard Glk)

Some quetsions have been solved for me, but my message system does not

12 messages 2001/09/03

[#20976] destructor — Frank Sonnemans <ruby@...>

Does Ruby have a destructor as in C++?

25 messages 2001/09/07

[#21218] Ruby objects <-> XML: anyone working on this? — senderista@... (Tobin Baker)

Are there any Ruby analogs of these two Python modules (xml_pickle,

13 messages 2001/09/15

[#21296] nested require files need path internally — Bob Gustafson <bobgus@...>

Version: 1.64

29 messages 2001/09/18
[#21298] Re: nested require files need path internally — David Alan Black <dblack@...> 2001/09/18

Hello --

[#21302] Re: nested require files need path internally — Bob Gustafson <bobgus@...> 2001/09/18

On Tue, 18 Sep 2001, David Alan Black wrote:

[#21303] Re: nested require files need path internally — matz@... (Yukihiro Matsumoto) 2001/09/18

Hi,

[#21306] Re: nested require files need path internally — Lars Christensen <larsch@...> 2001/09/18

On Tue, 18 Sep 2001, Yukihiro Matsumoto wrote:

[#21307] Re: nested require files need path internally — matz@... (Yukihiro Matsumoto) 2001/09/18

Hi,

[#21331] Re: nested require files need path internally — Paul Brannan <pbrannan@...> 2001/09/18

> The big difference is C++ search done in compile time, Ruby search

[#21340] Re: nested require files need path internally — matz@... (Yukihiro Matsumoto) 2001/09/18

Hi,

[#21353] Re: nested require files need path internally — Paul Brannan <pbrannan@...> 2001/09/18

On Wed, 19 Sep 2001, Yukihiro Matsumoto wrote:

[#21366] Re: nested require files need path internally — matz@... (Yukihiro Matsumoto) 2001/09/19

Hi,

[#21368] Re: nested require files need path internally — "Julian Fitzell" <julian-ml@...4.com> 2001/09/19

On 19/09/2001 at 10:12 AM matz@ruby-lang.org wrote:

[#21376] Re: nested require files need path internally — matz@... (Yukihiro Matsumoto) 2001/09/19

Hi,

[#21406] Re: nested require files need path internally — Paul Brannan <pbrannan@...> 2001/09/19

On Wed, 19 Sep 2001, Yukihiro Matsumoto wrote:

[#21315] Suggestions for new CGI lib — anders@... (Anders Johannsen)

From the comp.lang.ruby thread "Minor cgi.rb question" (2001-09-03), I

21 messages 2001/09/18

[#21413] Ruby/objects book in style of The Little Lisper — Brian Marick <marick@...>

I fell in love with Lisp in the early 80's. Back then, I read a book called

36 messages 2001/09/19
[#21420] Re: Ruby/objects book in style of The Little Lisper — Christopher Sawtell <csawtell@...> 2001/09/20

On 20 Sep 2001 06:19:44 +0900, Brian Marick wrote:

[#21479] Re: Ruby/objects book in style of The Little Lisper — Kevin Smith <kevinbsmith@...> 2001/09/21

--- Christopher Sawtell <csawtell@paradise.net.nz> wrote:

[#21491] SV: Re: Ruby/objects book in style of The Little Lisper — "Mikkel Damsgaard" <mikkel_damsgaard@...> 2001/09/21

[#21494] Re: SV: Re: Ruby/objects book in style of The Little Lisper — Kevin Smith <kevinbsmith@...> 2001/09/21

--- Mikkel Damsgaard <mikkel_damsgaard@mailme.dk> wrote:

[#21510] Re: SV: Re: Ruby/objects book in style of The Little Lisper — Todd Gillespie <toddg@...> 2001/09/22

On Sat, 22 Sep 2001, Kevin Smith wrote:

[#21514] Re: SV: Re: Ruby/objects book in style of The Little Lisper — Kevin Smith <kevinbsmith@...> 2001/09/22

--- Todd Gillespie <toddg@mail.ma.utexas.edu> wrote:

[#21535] irb — Fabio <fabio.spelta@...>

Hello. :) I'm new here, and I have not found an archive of the previous

15 messages 2001/09/22

[#21616] opening a named pipe? — "Avdi B. Grimm" <avdi@...>

I'm having trouble reading from a named pipe in linux. basicly, I'm

12 messages 2001/09/24

[#21685] manipulating "immutable" objects such as Fixnum from within callbacks & al... — Guillaume Cottenceau <gc@...>

Hello,

15 messages 2001/09/25

[#21798] Ruby internal (guide to the source) — "Benoit Cerrina" <benoit.cerrina@...>

Hi,

22 messages 2001/09/28

[ruby-talk:20672] Re: corresponding "non-bang" method to []=

From: Michael Neumann <neumann@...>
Date: 2001-09-01 15:44:59 UTC
List: ruby-talk #20672
Tobias Reif wrote:
> Hi,

Hi,

> There's "collect", and the bang version "collect!"
> 
> AFAICS, []= is bang. What's the non-bang version?

There's no one.
Does it make sense to have one? Not for me.
You may copy the receiver before with dup or clone, like Python's does with [:] when
changing an array inside a for-loop.

> I'm trying to modify specific members of an array, depending on their 
> position in the array ("second and last get a newline" etc.).

> I'm working my way through the docs, faqs, and the Pickaxe.
> Now after hours of trying, I only got it to work using a dirty hack.
> I'm looking for a nice way.
> 
> So because in collect there is no index passed to the block, I need to 
> use each_index, where I need to use []= to set the new value. (AFAIK)
> 
> But I don't want to modify the original, because I need to modify it 
> differently in another method starting from it's previous state.
> 
> In pseudo-code:
> 
> an_array.each_index do |x|
>   new_val = an_array.at(x) + "\n"
>   if (x == 2) or (x == (an_array.size - 1))
>    an_array.set_at(x,new_val)
>   end
> end

  an_array.dup.each_index do |x|
     ...
  end

should do it.

> or
> 
> an_array.collect |index,item|
>    if (index == 2) or (index == (an_array.size - 1))
>      item + "\n"
>    else
>      item
>    end
> end

How about:

  an_array[0..1]  + [an_array[2]  + "\n"] + 
  an_array[3..-2] + [an_array[-1] + "\n"] 

Alternatively, you may use a counter:

  index = -1
  an_array.collect do |item|
     index += 1
     if (index == 2) or (index == (an_array.size - 1))
       item + "\n"
     else
       item
     end
  end

or otherwise create an array that contains subarrays with "index,item" as elements:

  an_array.collect {|i| [nil, i]}.each_with_index{|i, e| e[0] = i}.collect do |index, item|
    ... proceed as above
  end


Regards,

  Michael

-- 
Michael Neumann
merlin.zwo InfoDesign GmbH
http://www.merlin-zwo.de

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