MATLAB: Extracting data based on categories

categories;extracting data from vectors

I have a table (z) with two columns, year and annual precipitation. I have a separate vector (E) of three categories (0,1,2) that correspond to the years in the first table. The categories are unevenly spaced. I would like to create three new tables of year and annual precipitation, one for each category. How do I extract the correct year and precipitation data for each category and populate new tables?
z=['01-Jan-1973'	0.0114583333333333
'01-Jan-1974'	0.0918518518518519
'01-Jan-1975'	0.0529032258064516
'01-Jan-1976'	0.213571428571429
'01-Jan-1977'	0.0857692307692308]
E=[0 1 0 2 1]
I would like to create three new tables in the same format as z, like below.
A=['01-Jan-1973'	0.0114583333333333
   '01-Jan-1975'	0.0529032258064516]
B=['01-Jan-1974'	0.0918518518518519
   '01-Jan-1977'	0.0857692307692308]
C=['01-Jan-1976'	0.213571428571429]
My actual tables and vectors are 1×79, making extracting the three new tables challenging to do by hand.

Best Answer

The splitapply function (R2015b and later releases) is perfect for this! 
z = {'01-Jan-1973'	0.0114583333333333
    '01-Jan-1974'	0.0918518518518519
    '01-Jan-1975'	0.0529032258064516
    '01-Jan-1976'	0.213571428571429
    '01-Jan-1977'	0.0857692307692308};
E=[0 1 0 2 1];
Out = splitapply(@(x){x}, z, E(:)+1);
A = Out{1}
B = Out{2}
C = Out{3}
producing: 
A =
  2×2 cell array
    {'01-Jan-1973'}    {[0.0114583333333333]}
    {'01-Jan-1975'}    {[0.0529032258064516]}
B =
  2×2 cell array
    {'01-Jan-1974'}    {[0.0918518518518519]}
    {'01-Jan-1977'}    {[0.0857692307692308]}
C =
  1×2 cell array
    {'01-Jan-1976'}    {[0.213571428571429]}
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