Question

I am reading a JSON like this:

[
  {
    "Low": 8.63,
    "Volume": 14211900,
    "Date": "2012-10-26",
    "High": 8.79,
    "Close": 8.65,
    "Adj Close": 8.65,
    "Open": 8.7
  },
  {
    "Low": 8.65,
    "Volume": 12167500,
    "Date": "2012-10-25",
    "High": 8.81,
    "Close": 8.73,
    "Adj Close": 8.73,
    "Open": 8.76
  },
  {
    "Low": 8.68,
    "Volume": 20239700,
    "Date": "2012-10-24",
    "High": 8.92,
    "Close": 8.7,
    "Adj Close": 8.7,
    "Open": 8.85
  },
  {
    "Low": 8.78,
    "Volume": 23433900,
    "Date": "2012-10-23",
    "High": 8.94,
    "Close": 8.78,
    "Adj Close": 8.78,
    "Open": 8.93
  }
]

Using this:

json = File.read("#{symbols[0]}.json")

Then doing this:

result = JSON.parse(json)

Then, when I want to select the first value for the key value “Low”, I did this:

puts result[0]['Low']

This returned 58.75 (correct).

But I want to get the first three values for “Low”. I tried doing the following, but it doesn’t work (says can’t convert string to integer). Why?

puts result[0..2]['Low']

Answer 1

results = [
  {"Low"=>58.75, "Volume"=>163200, "Date"=>"1962-02-01", "High"=>59.63, "Close"=>59.38, "Adj Close"=>0.61, "Open"=>59.63},
  {"Low"=>59.63, "Volume"=>134400, "Date"=>"1962-01-31", "High"=>60.0, "Close"=>59.75, "Adj Close"=>0.62, "Open"=>59.88},
  {"Low"=>59.13, "Volume"=>91200, "Date"=>"1962-01-26", "High"=>59.38, "Close"=>59.38, "Adj Close"=>0.61, "Open"=>59.13},
  {"Low"=>59.13, "Volume"=>91200, "Date"=>"1962-01-25", "High"=>59.88, "Close"=>59.13, "Adj Close"=>0.61, "Open"=>59.75},
  {"Low"=>58.5, "Volume"=>110400, "Date"=>"1962-01-24", "High"=>60.13, "Close"=>59.75, "Adj Close"=>0.62, "Open"=>60.13}
]
results[0..2].collect {|element| element['Low']}
>> [58.75, 59.63, 59.13]