多鍵哈希的最大值

Question

這是我的哈希（在Json中） 我需要獲取每個「高」值的最大值。例如，在這種情況下是16.94

如何在Ruby中得到這個？

我試圖與[]的.max功能，但我不知道來設置「鍵」，其中valutate最大

{ 
"query": { 
    "count": 124, 
    "created": "2012-03-21T20:45:39Z", 
    "lang": "en-US", 
    "results": { 
    "quote": [ 
    { 
    "date": "2010-03-10", 
    "Date": "2010-03-10", 
    "Open": "16.51", 
    "High": "16.94", 
    "Low": "16.51", 
    "Close": "16.79", 
    "Volume": "33088600", 
    "Adj_Close": "16.79" 
    }, 
    { 
    "date": "2010-03-09", 
    "Date": "2010-03-09", 
    "Open": "16.41", 
    "High": "16.72", 
    "Low": "16.40", 
    "Close": "16.53", 
    "Volume": "20755200", 
    "Adj_Close": "16.53" 
    }, 
    { 
    "date": "2010-03-08", 
    "Date": "2010-03-08", 
    "Open": "16.32", 
    "High": "16.61", 
    "Low": "16.30", 
    "Close": "16.52", 
    "Volume": "30554000", 
    "Adj_Close": "16.52" 
    }, 
    { 
    "date": "2010-03-05", 
    "Date": "2010-03-05", 
    "Open": "15.89", 
    "High": "16.38", 
    "Low": "15.89", 
    "Close": "16.06", 
    "Volume": "21415000", 
    "Adj_Close": "16.06" 
    } 

Answer 1

假設quotes包含數組（JSON解析後），該是"quote"鍵的值，你可以使用max_by：

quotes.max_by { |quote| quote["High"].to_f }["High"].to_f #=> 16.94 

另外，您可以使用map & max：

quotes.map { |quote| quote["High"].to_f }.max 

Answer 2

require 'yajl' 
data = Yajl::Parser.parse json 
data["query"]["results"]["quote"].max_by{|q| q["High"].to_f} 
#=> {"date"=>"2010-03-10", 
"Date"=>"2010-03-10", 
"Open"=>"16.51", 
"High"=>"16.94", 
"Low"=>"16.51", 
"Close"=>"16.79", 
"Volume"=>"33088600", 
"Adj_Close"=>"16.79"}