Re: Ruby List

Die_Optimisten · 13 January 2022 08:57

Hi

No, there is just Array, which is a list.

Maybe there are some gems providing real arrays.

Opti

Edward1 · 13 January 2022 10:04

Just out of curiosity, what benefits are you looking for that aren't
already in Ruby's implementation of an Array?

Edward

···

On 13.01.22 09:57, Die Optimisten wrote:

Hi

No, there is just Array, which is a list.

Maybe there are some gems providing real arrays.

Opti

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--
Freundliche Grüsse

Edward Caulfield

Yamada · 13 January 2022 10:19

Random access to Array is o(1), while to List is o(n).
Please see this article:

Python by default has no Array too, but Array exists in its Numpy library.

ありがとう
えりな

···

On Thu, Jan 13, 2022 at 6:04 PM Edward <edward.caulfield@gmx.ch> wrote:

Just out of curiosity, what benefits are you looking for that aren't
already in Ruby's implementation of an Array?

Edward

On 13.01.22 09:57, Die Optimisten wrote:
> Hi
>
> No, there is just Array, which is a list.
>
> Maybe there are some gems providing real arrays.
>
> Opti
>
>
>
> Unsubscribe: <mailto:ruby-talk-request@ruby-lang.org
?subject=unsubscribe>
> <http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-talk>

--
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Edward Caulfield

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Yamada · 13 January 2022 10:22

A developer from Scala group says, "never use Array unless you know what
you are doing exactly".
List is suitable for 99% of jobs IMO. But sometimes we do need a high
performance computing library.

ありがとう
えりな

···

On Thu, Jan 13, 2022 at 6:19 PM Yamadaえりな <yamoerina@gmail.com> wrote:

Random access to Array is o(1), while to List is o(n).
Please see this article:
Lists Part III: Lists vs Arrays. Data Structures in Ruby | by D. L. Jerome | Medium

Python by default has no Array too, but Array exists in its Numpy library.

ありがとう
えりな

On Thu, Jan 13, 2022 at 6:04 PM Edward <edward.caulfield@gmx.ch> wrote:

Just out of curiosity, what benefits are you looking for that aren't
already in Ruby's implementation of an Array?

Edward

On 13.01.22 09:57, Die Optimisten wrote:
> Hi
>
> No, there is just Array, which is a list.
>
> Maybe there are some gems providing real arrays.
>
> Opti
>
>
>
> Unsubscribe: <mailto:ruby-talk-request@ruby-lang.org
?subject=unsubscribe>
> <http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-talk>

--
Freundliche Grüsse

Edward Caulfield

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Gerard_Fowley · 13 January 2022 17:40

Benchmarks say Array access is O(1):

3.1.0 :156 > array_1k = Array.new(1000,0)
=>
[0,
...
3.1.0 :157 > puts Benchmark.measure { 1_000_000.times { |n|
array_1k[rand*1_000] } }
  0.218302 0.000000 0.218302 ( 0.218310)
=> nil
3.1.0 :158 > puts Benchmark.measure { 1_000_000.times { |n|
array_1k[rand*1_000] } }
  0.235638 0.000000 0.235638 ( 0.235650)
=> nil
3.1.0 :159 > array_100k = Array.new(100000,0)
=>
[0,
...
3.1.0 :160 > puts Benchmark.measure { 1_000_000.times { |n|
array_100k[rand*100_000] } }
  0.213250 0.000000 0.213250 ( 0.213260)
=> nil
3.1.0 :161 > puts Benchmark.measure { 1_000_000.times { |n|
array_100k[rand*100_000] } }
  0.204273 0.000000 0.204273 ( 0.204281)
=> nil
3.1.0 :162 > puts Benchmark.measure { 1_000_000.times { |n|
array_100k[rand*100_000] } }
  0.224937 0.000000 0.224937 ( 0.225697)
=> nil

Source says it's an array:

<goog_628926836>

github.com

ruby/ruby/blob/acd1f45a5c0a35bcafef8c31b1429126a5efa3ea/include/ruby/internal/core/rarray.h#L213


      
          #endif
                          VALUE shared_root;
                      } aux;
          
                      /**
                       * Pointer to the C array that holds the elements of the array.  In
                       * the old days  each array had dedicated memory  regions.  That is
                       * no  longer  true today,  but  there  still  are arrays  of  such
                       * properties.  This field could be used to point such things.
                       */
                      const VALUE *ptr;
                  } heap;
          
                  /**
                   * Embedded elements.  When an array is short enough, it uses this area
                   * to store its elements.  In this  case the length is encoded into the
                   * flags.
                   */
                  const VALUE ary[RARRAY_EMBED_LEN_MAX];
              } as;
          };

/**
* Pointer to the C array that holds the elements of the array. In
* the old days each array had dedicated memory regions. That is
* no longer true today, but there still are arrays of such
* properties. This field could be used to point such things.
*/
const VALUE *ptr;

It may be different for other Ruby implementations.

The sizing of a dynamic array is an exercise in trade-offs. If you have
large amounts of in-memory data and specific performance requirements,
benchmark high perf libraries for your situation.

-gf-

···

On Thu, Jan 13, 2022 at 5:22 AM Yamadaえりな <yamoerina@gmail.com> wrote:

A developer from Scala group says, "never use Array unless you know what
you are doing exactly".
List is suitable for 99% of jobs IMO. But sometimes we do need a high
performance computing library.

ありがとう
えりな

On Thu, Jan 13, 2022 at 6:19 PM Yamadaえりな <yamoerina@gmail.com> wrote:

Random access to Array is o(1), while to List is o(n).
Please see this article:
Lists Part III: Lists vs Arrays. Data Structures in Ruby | by D. L. Jerome | Medium

Python by default has no Array too, but Array exists in its Numpy library.

ありがとう
えりな

On Thu, Jan 13, 2022 at 6:04 PM Edward <edward.caulfield@gmx.ch> wrote:

Just out of curiosity, what benefits are you looking for that aren't
already in Ruby's implementation of an Array?

Edward

On 13.01.22 09:57, Die Optimisten wrote:
> Hi
>
> No, there is just Array, which is a list.
>
> Maybe there are some gems providing real arrays.
>
> Opti
>
>
>
> Unsubscribe: <mailto:ruby-talk-request@ruby-lang.org
?subject=unsubscribe>
> <http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-talk>

--
Freundliche Grüsse

Edward Caulfield

Unsubscribe: <mailto:ruby-talk-request@ruby-lang.org
?subject=unsubscribe>
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Yamada · 14 January 2022 00:53

Thank you for the benchmark and the document. Glad to see the results.
I will take time to test it on my end.

ありがとう
えりな

···

On Fri, Jan 14, 2022 at 1:41 AM Gerard Fowley <gerard.fowley@iqeo.net> wrote:

Benchmarks say Array access is O(1):

3.1.0 :156 > array_1k = Array.new(1000,0)
=>
[0,
...
3.1.0 :157 > puts Benchmark.measure { 1_000_000.times { |n|
array_1k[rand*1_000] } }
  0.218302 0.000000 0.218302 ( 0.218310)
=> nil
3.1.0 :158 > puts Benchmark.measure { 1_000_000.times { |n|
array_1k[rand*1_000] } }
  0.235638 0.000000 0.235638 ( 0.235650)
=> nil
3.1.0 :159 > array_100k = Array.new(100000,0)
=>
[0,
...
3.1.0 :160 > puts Benchmark.measure { 1_000_000.times { |n|
array_100k[rand*100_000] } }
  0.213250 0.000000 0.213250 ( 0.213260)
=> nil
3.1.0 :161 > puts Benchmark.measure { 1_000_000.times { |n|
array_100k[rand*100_000] } }
  0.204273 0.000000 0.204273 ( 0.204281)
=> nil
3.1.0 :162 > puts Benchmark.measure { 1_000_000.times { |n|
array_100k[rand*100_000] } }
  0.224937 0.000000 0.224937 ( 0.225697)
=> nil

Source says it's an array:

<http://goog_628926836>

https://github.com/ruby/ruby/blob/acd1f45a5c0a35bcafef8c31b1429126a5efa3ea/include/ruby/internal/core/rarray.h#L213

/**
* Pointer to the C array that holds the elements of the array. In
* the old days each array had dedicated memory regions. That is
* no longer true today, but there still are arrays of such
* properties. This field could be used to point such things.
*/
const VALUE *ptr;

It may be different for other Ruby implementations.

The sizing of a dynamic array is an exercise in trade-offs. If you have
large amounts of in-memory data and specific performance requirements,
benchmark high perf libraries for your situation.

-gf-

On Thu, Jan 13, 2022 at 5:22 AM Yamadaえりな <yamoerina@gmail.com> wrote:

A developer from Scala group says, "never use Array unless you know what
you are doing exactly".
List is suitable for 99% of jobs IMO. But sometimes we do need a high
performance computing library.

ありがとう
えりな

On Thu, Jan 13, 2022 at 6:19 PM Yamadaえりな <yamoerina@gmail.com> wrote:

Random access to Array is o(1), while to List is o(n).
Please see this article:
https://medium.com/@dljerome/lists-part-iii-lists-vs-arrays-60bdced64eed

Python by default has no Array too, but Array exists in its Numpy
library.

ありがとう
えりな

On Thu, Jan 13, 2022 at 6:04 PM Edward <edward.caulfield@gmx.ch> wrote:

Just out of curiosity, what benefits are you looking for that aren't
already in Ruby's implementation of an Array?

Edward

On 13.01.22 09:57, Die Optimisten wrote:
> Hi
>
> No, there is just Array, which is a list.
>
> Maybe there are some gems providing real arrays.
>
> Opti
>
>
>
> Unsubscribe: <mailto:ruby-talk-request@ruby-lang.org
?subject=unsubscribe>
> <http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-talk>

--
Freundliche Grüsse

Edward Caulfield

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?subject=unsubscribe>
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