How To

Write simple Interactive JavaScript statements

Lets HD-IN Interactive JavaScript

Interactive Javascript console is a handy tool to execute pig parsing, upload files, run C# streaming Map/Reduce jobs,
Here are some basic commands to get going with interactive Javascripts  

  • Samle Data Structure
proplistingid
 
Suburbid
 
proptype
 
propsellertype
 
 propprice
 
postedon
 
 
10100
 
2130
 
Land
 
Con​tact Owner
   
....
 
10101
 
1231
 
House
 
Contact Builder
   ...
 
10102
 
2130
 
Land
 
Contact Agent
   
 ..  
2341
 
House
 ..
Contact Builder
   
 ..  
2456
 
Land
 
Contact Owner
   
 ..  
2130
 
Land
 
Contact Agent
   
                                            

  • Simple Interactive JavaScript statements 
 
 Task Statements  
 Assigning value to variable 

  inputfilelocation = "./input/RealEstate.txt" 

Schema definition:
Pig datatype can be inferred for 
schema definition (chararray, bytearray)
If unknown, can be left blank		  schema = "Suburbid:int,proptype:chararray,propsellertype:chararray"

 Filter (Where statement) 

  pig.from(inputfilelocation, schema).where("Suburbid == '2130'").select("Suburbid,proptype,propsellertype")
 Grouping statement
group -> Suburbid 
q0 -> output of grouping statement is
always a bag { tuple {}} (refer to Pig output)

Sample output:
2130, {(Contact Owner), (Contact Agent) , (Contact Agent)} 
1231, {(Contact Builder)} 
  output = pig.from(inputfilelocation, schema).groupBy
("Suburbid").select("group , q0.propsellertype").run()

 Group by two columns
Note : SUM can be applied 

Sample Output
Contact Agent  2130 2.0
Contact Builder      1231  1.0

  output = pig.from(inputfilelocation, schema).groupBy
(function() { return [propsellertype, Suburbid ]; }).select
("group.$0, group.$1,SUM(q0.$0)").run()

 Sample Join statement
Note, same input file will not be accepted
 pig.from("inputfile1", "o1:chararray, o2:chararray, o3:chararray").join
(pig.from("inputfile2","b1:chararray,b2:chararray,b3:chararray"), "$0","$0").select
("*").run()
   
  • Part 2 will contd soon...

References

  • http://social.technet.microsoft.com/wiki/contents/articles/13831.working-with-data-in-windows-azure-hdinsight-service.aspx
  • http://social.technet.microsoft.com/wiki/contents/articles/7180.data-visualization-on-the-interactive-javascript-console.aspx.