2D array assigns input to all inner arrays? [duplicate] - arrays

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Create multiple arrays in one line
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I'm trying to get the method input to be stored and outputted like this:
Want [ ["email addresses"], ["phone numbers"], ["names"] ] - > [["bobsmith#example.com","sallyfield#example.com"],["555-555-5555","111-111-1111"],["Bob Smith","Sally Field"]]
This is my code:
def hash_2_array contacts
2 # Extract like info from each hash into arrays
3 stringArr = Array.new(3,Array.new(2)) #=> [ [ nil,nil] , [nil,nil] , [nil,nil] ]
4
5 if contacts.empty?
6 return nonsense = Array.new(3, Array.new)
7 else
8 n=0 #name counter
9 e=0 #email counter
10 p=0 #phone counter
11 contacts.each do |key, value|
12 stringArr[2][n] = key.to_s #adds name to array
13 n+=1
14 value.each do |key2, value2|
15 if key2.to_s.eql?("email")
16 stringArr[0][e] = value2.to_s #adds email address to array
17 e+=1
18 else
19 stringArr[1][p] = value2.to_s #adds phone number to array
20 p+=1
21 end
22 end
23 end
24 end
25 return stringArr
26 end
27
28
29 hash_2_array({:"Bob Smith"=>{:email=>"bobsmith#example.com", :phone=>"555-555-5555"}, :"Sally Field"=>{:email=>"sallyfield#example.com", :phone=>"111-111-1111"}})
It returns:
got: [["555-555-5555", "111-111-1111"], ["555-555-5555", "111-111-1111"], ["555-555-5555", "111-111-1111"]]
It's really confusing why it's not just assigning only the the index in the array that I'm specifying. I think this code worked before, but now it's broken somehow. Any help would be great

Answer 1

From the fine manual:
new(size=0, default=nil)
new(array)
new(size) {|index| block }
[...]
Common gotchas
When sending the second parameter, the same object will be used as the value for all the array elements:
a = Array.new(2, Hash.new)
# => [{}, {}]
a[0]['cat'] = 'feline'
a # => [{"cat"=>"feline"}, {"cat"=>"feline"}]
a[1]['cat'] = 'Felix'
a # => [{"cat"=>"Felix"}, {"cat"=>"Felix"}]
If multiple copies are what you want, you should use the block version which uses the result of that block each time an element of the array needs to be initialized:
a = Array.new(2) { Hash.new }
a[0]['cat'] = 'feline'
a # => [{"cat"=>"feline"}, {}]
When you say this:
stringArr = Array.new(3,Array.new(2))
You're creating an array with three elements but all those elements are exactly the same array. You want an array that contains three different arrays as elements:
stringArr = Array.new(3) { Array.new(2) }