title: reformat large csv dataset using d3 for nvd3
body: <p>I have a csv dataset with multiple mentions of the same item (ie conflict name - england IRA, israel palestine etc), and values of dates and number_of_casualties for each specified date.</p>
  
  <p>I want to express this using nvd3 stacked area chart:
  <a href="http://nvd3.org/examples/stackedArea.html" rel="nofollow noreferrer">http://nvd3.org/examples/stackedArea.html</a></p>
  
  <p>the format that it uses in the example is:</p>
  
  <pre><code>key : "category a"
  values: [ [ date , amount ] , [ date , amount ] ....]
  </code></pre>
  
  <p>here's some fo the actual code in the example:</p>
  
  <pre><code>   {
              "key" : "Energy" ,
              "values" : [ [ 1138683600000 , 1.544303464167] , [ 1141102800000 , 1.4387289432421] , [ 1143781200000 , 0] , [ 1146369600000 , 0] , [ 1149048000000 , 0] , [ 1151640000000 , 1.328626801128] , [ 1154318400000 , 1.2874050802627] , [ 1156996800000 , 1.0872743105593] , [ 1159588800000 , 0.96042562635813] , [ 1162270800000 , 0.93139372870616] , [ 1164862800000 , 0.94432167305385] , [ 1167541200000 , 1.277750166208] , [ 1170219600000 , 1.2204893886811] , [ 1172638800000 , 1.207489123122] , [ 1175313600000 , 1.2490651414113] , [ 1177905600000 , 1.2593129913052] , [ 1180584000000 , 1.373329808388] , [ 1183176000000 , 0] , [ 1185854400000 , 0] , [ 1188532800000 , 0] , [ 1191124800000 , 0] , [ 1193803200000 , 0] , [ 1196398800000 , 0] , [ 1199077200000 , 0] , [ 1201755600000 , 0] , [ 1204261200000 , 0] , [ 1206936000000 , 0] , [ 1209528000000 , 0] , [ 1212206400000 , 0] , [ 1214798400000 , 0] , [ 1217476800000 , 0] , [ 1220155200000 , 0] , [ 1222747200000 , 1.4516108933695] , [ 1225425600000 , 1.1856025268225] , [ 1228021200000 , 1.3430470355439] , [ 1230699600000 , 2.2752595354509] , [ 1233378000000 , 2.4031560010523] , [ 1235797200000 , 2.0822430731926] , [ 1238472000000 , 1.5640902826938] , [ 1241064000000 , 1.5812873972356] , [ 1243742400000 , 1.9462448548894] , [ 1246334400000 , 2.9464870223957] , [ 1249012800000 , 3.0744699383222] , [ 1251691200000 , 2.9422304628446] , [ 1254283200000 , 2.7503075599999] , [ 1256961600000 , 2.6506701800427] , [ 1259557200000 , 2.8005425319977] , [ 1262235600000 , 2.6816184971185] , [ 1264914000000 , 2.681206271327] , [ 1267333200000 , 2.8195488011259] , [ 1270008000000 , 0] , [ 1272600000000 , 0] , [ 1275278400000 , 0] , [ 1277870400000 , 1.0687057346382] , [ 1280548800000 , 1.2539400544134] , [ 1283227200000 , 1.1862969445955] , [ 1285819200000 , 0] , [ 1288497600000 , 0] , [ 1291093200000 , 0] , [ 1293771600000 , 0] , [ 1296450000000 , 1.941972859484] , [ 1298869200000 , 2.1142247697552] , [ 1301544000000 , 2.3788590206824] , [ 1304136000000 , 2.5337302877545] , [ 1306814400000 , 2.3163370395199] , [ 1309406400000 , 2.0645451843195] , [ 1312084800000 , 2.1004446672411] , [ 1314763200000 , 3.6301875804303] , [ 1317355200000 , 2.454204664652] , [ 1320033600000 , 2.196082370894] , [ 1322629200000 , 2.3358418255202] , [ 1325307600000 , 0] , [ 1327986000000 , 0] , [ 1330491600000 , 0] , [ 1333166400000 , 0.39001201038526] , [ 1335758400000 , 0.30945472725559] , [ 1338436800000 , 0.31062439305591]]
          }
  </code></pre>
  
  <p>two questions pls:</p>
  
  <ol>
  <li>How to I aggregate and format my csv data to that format?</li>
  <li>What time format is that?</li>
  </ol>