Thanks .. I converted the text-->string --> Float.
I am trying to calculate the average of a very large set of numbers. You are right...I plan to use a dummy key (its not null as i said before) as input to reduce. Then in reduce when sorted, i will have a single record as <key,<n1,n2,n3...>> which i will use to calculate the avg. Regards, Pavan ________________________________ From: Owen O'Malley <[EMAIL PROTECTED]> To: [email protected] Sent: Sunday, 26 October, 2008 1:24:43 AM Subject: Re: writable class to be used to read floating point values from input? On Oct 25, 2008, at 8:32 PM, pols cut wrote: > I am trying to write a map reduce function which takes take the > following types of <key,value> pairs > > > Map function -- should read floating point values (i dont really > care about key) > it should output <null,floatwritable> If the input is stored in a text file, using TextInputFormat is right. Your map inputs will be: LongWritable, Text Just use the Text and convert it to a Double. > reduce -- input- <null,floatwritable> > output <null,floatwritable> This doesn't make any sense. How should the input to the reduce be sorted? By the float? In that case, it would be: FloatWritable, NullWritable You will get one call to the reduce for each distinct float value the maps generate. The reduce can iterate through the NullWritables to see how many times that key was generated. -- Owen Bollywood news, movie reviews, film trailers and more! Go to http://in.movies.yahoo.com/
