Basic Examples 
(2)
 

Group the data by the first element in each list, then get the last element of each list, and then compute the
Mean
of each grouping:
In[278]:=
[◼]
MapReduceOperator
[FirstLast,Mean][{{a,x},{b,v},{a,y},{a,z},{b,w}}]
Out[278]=
a
1
3
(x+y+z),b
v+w
2

———
Group a list of integers according to their parity, compute their square roots, and display the results as column vectors:
In[287]:=
[◼]
MapReduceOperator
[PositiveSqrt,MatrixForm][Range[-4,4]]
Out[287]=
False
2

3

2

0
,True
1
2
3
2


Scope 
(2)
 


Options 
(2)
 


Applications 
(4)
 


Possible Issues 
(1)
 
