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I need something like this below.

products['first_category'][0] = ['aaa', 'bb', 'ccc']
products['first_category'][1] = ['aa', 'bb', 'cc']
products['first_category'][2] = ['a', 'b', 'c']
products['second_category'][0] = ['asd', 'sdfb', 'csdfd']
products['second_category'][1] = ['sdf', 'bsdf', 'dsfssd']
all_products = products['first_category'] + products['second_category']

This should produce an array of the form 

all_products[0] = ['aaa', 'bb', 'ccc']
all_products[1] = ['aa', 'bb', 'cc']
all_products[2] = ['a', 'b', 'c']
all_products[3] = ['asd', 'sdfb', 'csdfd']
all_products[4] = ['sdf', 'bsdf', 'dsfssd']

But I don't know how to implement this in ruby. I tried this but it gives error.

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  • 1
    "it gives error" - please include the error. Commented Dec 23, 2015 at 12:09

3 Answers 3

Reset to default
2 
▶ products = {}
#⇒ {}
▶ products['first_category'] = []
#⇒ []
▶ products['second_category'] = []
#⇒ []
▶ products['first_category'][0] = ['aaa', 'bb', 'ccc']
▶ products['first_category'][1] = ['aa', 'bb', 'cc']
▶ products['first_category'][2] = ['a', 'b', 'c']
▶ products['second_category'][0] = ['asd', 'sdfb', 'csdfd']
▶ products['second_category'][1] = ['sdf', 'bsdf', 'dsfssd']
▶ all_products = products['first_category'] + products['second_category']
#⇒ [
#  [0] [
#    [0] "aaa",
#    [1] "bb",
#    [2] "ccc"
#  ],
#  [1] [
#    [0] "aa",
#    [1] "bb",
#    [2] "cc"
#  ],
#  [2] [
#    [0] "a",
#    [1] "b",
#    [2] "c"
#  ],
#  [3] [
#    [0] "asd",
#    [1] "sdfb",
#    [2] "csdfd"
#  ],
#  [4] [
#    [0] "sdf",
#    [1] "bsdf",
#    [2] "dsfssd"
#  ]
# ]

The tricks here are:

  1. Since your top-level indices are strings, the object itself must be a hash rather than an array. Arrays might have integer indices only.
  2. All subarrays must be explicitly created before one might add elements to them.
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Comments

1

Your code is fine. Just use below line to create products (add it to top of your code snippet)

products = Hash.new {|hash, key| hash[key] = [] }

You need to use Hash as Array can't have non-numeric indices. Hash allows you to accepts its elements in array-like syntax even though it's a dictionary. In addition, the above code will ensure that if there is no entry for a given key, an empty array is used as its value and added to hash.

Working sample:

products = Hash.new {|hash, key| hash[key] = [] }

products['first_category'][0] = ['aaa', 'bb', 'ccc']
products['first_category'][1] = ['aa', 'bb', 'cc']
products['first_category'][2] = ['a', 'b', 'c']

products['second_category'][0] = ['asd', 'sdfb', 'csdfd']
products['second_category'][1] = ['sdf', 'bsdf', 'dsfssd']

all_products = products['first_category'] + products['second_category']

p all_products[0]
#=> ["aaa", "bb", "ccc"]
p all_products[1]
#=> ["aa", "bb", "cc"]
p all_products[2]
#=> ["a", "b", "c"]
p all_products[3]
#=> ["asd", "sdfb", "csdfd"]
p all_products[4]
#=> ["sdf", "bsdf", "dsfssd"]
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0

just try

all_products = products.values.flatten(1)

You take the values into an array ignoring the keys and flatten it to the level of 1

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