Hi, 

     I'd like to make an operation on an RDD that ONLY change the value of  some items, without make a full copy or full scan of each data.

     It is useful when I need to handle a large RDD, and each time I need only to change a little fraction of the data, and keeps other data unchanged. Certainly I don't want to make a full copy the data to the new RDD.

     For example, suppose I have a RDD that contains integer data from 0 to 100. What I want is to make the first element of the RDD changed from 0 to 1, other elements untouched. 

     I tried this, but it doesn't work:

     var rdd = parallelize(Range(0,100))
     rdd.mapPartitions({iter=> iter(0) = 1})
 
     The reported error is :   value update is not a member of Iterator[Int]


     Anyone knows how to make it work?