ruby - how to set a mixed array with an integer and a hash [closed]

Question

I want to populate an array that has an integer and a hash, something like:

my_a=[Integer,{}]

then for example I am trying to have:

my_a[5,{:direction=>'up'}]
my_a[5,{:speed=>'fast'}]
my_a[3,{:direction=>'up'}]
my_a[3,{:speed=>'slow'}]

but I get

ArgumentError: wrong number of arguments(2 for 1)

How do I set my_a to have an entry for 5 with :direction => 'up'?

Maybe the whole thing should be a hash?

Trying to find someway to store this:

[0,{:top => ' ―― '},{:top_mid => '|__|'},{:bot_mid => '|  |'},{:bot => '――'}]
[1,{:top => ' ―― '},{:top_mid => '|__|'},{:bot_mid => '|  |'},{:bot => '――'}]
[2,{:top => ' ―― '},{:top_mid => '|__|'},{:bot_mid => '|  |'},{:bot => '――'}]

Answer 1

I think you're looking for an array of hashes. Alternatively, if the numeric indices are not consecutive, a hash of hashes.

To create such an array, you can use an array literal ([...]) with hash literals ({...}) inside:

my_arr = [
  {:top => 'top0', :bot => 'bot0'},
  {:top => 'top1', :bot => 'bot1'}
]

(whitespace optional). Then my_arr[0] will refer to the first hash (with top0 and bot0 inside), and my_arr[1] will refer to the second hash. my_arr[0][:bot] will refer to the :bot value in the first hash, bot0.

Note that my_arr[2][:bot] will raise an exception since my_arr[2] is nil. Make sure to include any neccessary checks if you're accessing by an index.

See:

• the documentation on Array
• Array#[]
• Array#each
  ...
• the documentation on Hash
• Hash#[]
• Hash#each ...
• the documentation on Enumerable, that Array and Hash include, and its methods.

Answer 2

You wrote:

Trying to find someway to store this:

[0,{:top => ' ―― '},{:top_mid => '|__|'},{:bot_mid => '|  |'},{:bot => '――'}]
[1,{:top => ' ―― '},{:top_mid => '|__|'},{:bot_mid => '|  |'},{:bot => '――'}]
[2,{:top => ' ―― '},{:top_mid => '|__|'},{:bot_mid => '|  |'},{:bot => '――'}]

I don't think that's what you really want. What you show there is a discrete set of arrays, each of which has a single integer and a bunch of one-element hashes. I think you really want this:

a = [
  {:top => ' ―― ', :top_mid => '|__|', :bot_mid => '|  |', :bot => '――'},
  {:top => ' ―― ', :top_mid => '|__|', :bot_mid => '|  |', :bot => '――'},
  {:top => ' ―― ', :top_mid => '|__|', :bot_mid => '|  |', :bot => '――'}
]

With the above structure data, you can ask for items by index and name like so:

puts a[1][:top] #=> ' ―― '

You can create this either directly like I showed above, or you can add to it like so:

a = [] # Just an array; the contents are arbitrary

# Add an entire row at once…
a[0] = {:top => ' ―― ', :top_mid => '|__|', :bot_mid => '|  |', :bot => '――'}

# …or add to it piecemeal
a[1] = {} # An empty hash, waiting to be filled
a[1][:top] = ' ―― '
a[1][:bot] = ' ―― '
# et cetera

Note that if you do not know the index of each entry directly, but just want to add rows to the end, you can do:

a << {} # push this hash onto the end of the array
a.last[:top] = ' ―― '
# and so on

Answer 3

You are trying to store an hash with values of arrays of hashes. Try this:

my_a = {}
my_a[0] = [{:top => ' ―― '},{:top_mid => '|__|'},{:bot_mid => '|  |'},{:bot => '――'}]
my_a[1] = [{:top => ' ―― '},{:top_mid => '|__|'},{:bot_mid => '|  |'},{:bot => '――'}]
my_a[2] = [{:top => ' ―― '},{:top_mid => '|__|'},{:bot_mid => '|  |'},{:bot => '――'}]

Unless you want a hash of hashes...

my_a = {}
my_a[0] = {:top => ' ―― ', :top_mid => '|__|', :bot_mid => '|  |', :bot => '――'}
my_a[1] = {:top => ' ―― ', :top_mid => '|__|', :bot_mid => '|  |', :bot => '――'}
my_a[2] = {:top => ' ―― ', :top_mid => '|__|', :bot_mid => '|  |', :bot => '――'}

Also remember that Ruby is dynamically typed, and you can't declare the type stored in an array or hash.

Answer 4

Seems like you want to store a specific structure in an array or in a hash. If you don't want to create a class for that, you can use OpenStruct:

require 'ostruct'
item = OpenStruct.new(top: ' ―― ', top_mid: '|__|', bot_mid: '|  |', bot: '――')
#=> #<OpenStruct top=" ―― ", top_mid="|__|", bot_mid="|  |", bot="――">, 1=>#<OpenStruct top=" ―― ", top_mid="|__|", bot_mid="|  |", bot="――">

You can get and set the attributes like this:

item.top                    # get "top" value
# => ' ―― '

item.top = "other value"    # set "top" value

Multiple items can be stored in an array:

array = []   # shortcut for Array.new

10.times { |index|
  array << OpenStruct.new(top: ' ―― ', top_mid: '|__|', bot_mid: '|  |', bot: '――')
}

array        #=> [<OpenStruct ...>, 2=>#<OpenStruct ...>, ...]
array[0]     #=> <OpenStruct ...>
array[0].top #=> ' ―― '

Or in a hash with numeric keys:

hash = {}    # shortcut for Hash.new

1.upto(10) { |index|
  hash[index] = OpenStruct.new(top: ' ―― ', top_mid: '|__|', bot_mid: '|  |', bot: '――')
}

hash         #=> {1=>#<OpenStruct ...>, 2=>#<OpenStruct ...>, ...}
hash[1]      #=> <OpenStruct ...>
hash[1].top  #=> ' ―― '