Ruby hash of arrays issue

Question

I am new to ruby and its nuances but I am running into this issue that I dont quite know how to fix or understand:

If I create the hash:

test = JSON.parse('[
    {"values":[
        ["header 1", "header 2", "header 3"],
        ["value 1", "value 2", "value 3"]]
    }]
')

Then I access test.values[0] I get:

[[["header 1", "header 2", "header 3"], ["value 1", "value 2", "value 3"]]]

As you can see it adds an extra layer onto the array. where what I would expect it to return would be:

[["header 1", "header 2", "header 3"], ["value 1", "value 2", "value 3"]]

Can anyone explain this to me or help mitigate this issue?

thanks!

you shouldn't be calling .values on an array (which is what test is) — max pleaner
– max pleaner, Commented Oct 12, 2016 at 20:43
You should be getting a syntax error for undefined method. — tadman
– tadman, Commented Oct 12, 2016 at 20:50
Thank you to the people who responded to this post. It definitely is that values is a method, and the unintended consequences from that was that it didn't go in and grab the key then get the contents but instead called the method values. — niallsc
– niallsc, Commented Oct 12, 2016 at 21:15
It absolutely doesn't when I run that code in Ruby 2.3.1. Maybe you have some library added on that's adding that method, but it's non-standard. Are you using Hashie or something else that extends Hash? If you are that would be test[0].values not what you put there. — tadman
– tadman, Commented Oct 12, 2016 at 21:53

Karl Laurentius Roos · Accepted Answer · 2016-10-12 20:43:14Z

4

I'm fairly certain that you aren't accessing the data in the right way as this:

test = JSON.parse('[
    {"values":[
        ["header 1", "header 2", "header 3"],
        ["value 1", "value 2", "value 3"]]
    }]
')

puts test[0]['values'].inspect
puts test[0]['values'][0].inspect

outputs:

[["header 1", "header 2", "header 3"], ["value 1", "value 2", "value 3"]] ["header 1", "header 2", "header 3"]

answered Oct 12, 2016 at 20:43

Karl Laurentius Roos

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Comments

jusmat · Accepted Answer · 2016-10-12 21:30:52Z

1

Your JSON contains a key called values. In order to receive values from the hash try using it like this test[0]['values']. When using test[0].values you are actually calling Hash#values (instance method of Hash class) which returns all the values of every single key in your hash combined into the array.

answered Oct 12, 2016 at 21:30

jusmat

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