Dynamically create an unknown number of arrays


#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


#2

On 06.02.2009 17:21, Shandy N. 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

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


#3

Shandy N. 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]


#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


#5

7stud – wrote:

Shandy N. 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+/)