Dynamically create an unknown number of arrays

ruby-talk
1

I need to create an unknow number of arrays on the fly (could be 1 array
could be 10, I don't know), is there a way to do this in Ruby and also
name them dynamically? I also need to set those array's to a collection
of stuff found in a table. My Ruby is pretty rusty, and I am not sure if
I can simply set an array to a group of stuff. If I have rows in a table
that can be accessed by saying @user.table_name, can I say:

a = Array.new
a = @user.table_name

Thanks for any help,

-S

···

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2

You can say, or rather: write, that - but the effect would be disappointing. The second assignment simply overwrites the first one rendering it completely superfluous.

You can do this

arrays = Array.new(how_many) {}

Cheers

  robert

···

On 06.02.2009 17:21, Shandy Nantz wrote:

I need to create an unknow number of arrays on the fly (could be 1 array
could be 10, I don't know), is there a way to do this in Ruby and also
name them dynamically? I also need to set those array's to a collection
of stuff found in a table. My Ruby is pretty rusty, and I am not sure if
I can simply set an array to a group of stuff. If I have rows in a table
that can be accessed by saying @user.table_name, can I say:

a = Array.new
a = @user.table_name

3

Shandy Nantz wrote:

I need to create an unknow number of arrays on the fly (could be 1 array
could be 10, I don't know), is there a way to do this in Ruby and also
name them dynamically? I also need to set those array's to a collection
of stuff found in a table. My Ruby is pretty rusty, and I am not sure if
I can simply set an array to a group of stuff. If I have rows in a table
that can be accessed by saying @user.table_name, can I say:

a = Array.new
a = @user.table_name

Thanks for any help,

-S

--data.txt--
apple, banana, strawberry
10, 20, 30, 40
red blue green yellow black
100 200 300
a b c d

···

-----------

data =
num_arrays = rand(5)

File.open("data.txt") do |f|
  num_arrays.times do
    line = f.gets.strip()
    data << line.split("/,?\s*/")
  end
end

p data

--output:--
[["apple, banana, strawberry"], ["10, 20, 30, 40"], ["red blue green
yellow black"]]

The names of the arrays are: data[0], data[1], data[2]

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4

You can say, or rather: write, that - but the effect would be
disappointing. The second assignment simply overwrites the first one
rendering it completely superfluous.

You can do this

arrays = Array.new(how_many) {}

Cheers

  robert

I have done some digging around and this is what I have written down on
paper - not tested yet at all:

@array_count = @user.tabledef.count #returns a 3, for example
@count = 0

until @count == @array_count - 1 do
  eval("#{@count} = @user.tabledefs["#{count}.items)
  @count += 1
end

What I was hoping is that this would return 3 distintive arrays, is this
not correct? What I am trying to do is build a table with x many columns
and y many rows but before hand I know neither what x or y is going to
be.

Also, assuming the above codes works (and assuming that there is not an
easier way to do this, which I'm thinking there is) how do I access the
arrays? Are they stored in a hash? or a variable? Thanks,

-S

···

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5

7stud -- wrote:

Shandy Nantz wrote:

I need to create an unknow number of arrays on the fly (could be 1 array
could be 10, I don't know), is there a way to do this in Ruby and also
name them dynamically? I also need to set those array's to a collection
of stuff found in a table. My Ruby is pretty rusty, and I am not sure if
I can simply set an array to a group of stuff. If I have rows in a table
that can be accessed by saying @user.table_name, can I say:

a = Array.new
a = @user.table_name

Thanks for any help,

-S

--data.txt--
apple, banana, strawberry
10, 20, 30, 40
red blue green yellow black
100 200 300
a b c d
-----------

data =
num_arrays = rand(5)

File.open("data.txt") do |f|
  num_arrays.times do
    line = f.gets.strip()
    data << line.split("/,?\s*/")
  end
end

p data

--output:--
[["apple, banana, strawberry"], ["10, 20, 30, 40"], ["red blue green
yellow black"]]

The names of the arrays are: data[0], data[1], data[2]

Whoops. No quotes around regex's in ruby, and that regex doesn't work
anyway.

If you have comma delimited data like this:

--data.txt-----------
apple, banana, strawberry
10, 20, 30, 40
red, blue, green, yellow, black
100, 200, 300
a, b, c, d

···

---------------------

you can use this for the regex:

pieces = line.split(/,\s*/)

If your data is space delimited, you can use:

pieces = line.split(/\s+/)

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