title: How to group by and return list in rx java
body: <p>I'm trying to create group list based on certain conditions in Rxjava.</p>
  
  <p>Below is my response:</p>
  
  <pre><code>{  
     "dates":[  
        {  
           "date":18,
           "value":"1"
        },
        {  
           "date":18,
           "value":"2"
        },
        {  
           "date":18,
           "value":"3"
        },
        {  
           "date":19,
           "value":"1"
        },
        {  
           "date":19,
           "value":"2"
        },
        {  
           "date":19,
           "value":"3"
        },
        {  
           "date":19,
           "value":"4"
        }
     ]
  }
  </code></pre>
  
  <p>How can group by the values 18 [value 1, value 2, value 3, highestvalue= 3, lowestvalue = 1] 
  19[value 1, value 2, value 3, value 4,highestvalue= 4, lowestvalue = 1] using Rxjava</p>
  
  <p>Note: I can create using for loop but the response will be fetched from the server and since it is returning observable thought of using rx java functionality. </p>
  
  <p>Anyhelp will be really appreciated. </p>
  
  <p>Thank you,
  Shanthi</p>