Trying to sort a table by entry in specific column

I am working on a problem were I need to take the mean of two variables from several trials in a table. I was trying to set up a for loop based on the entry in the first column having constant values (example, all the 1's) to take the mean of column 2 and column 3 for each constant value (all the 1's in the first column). I ran into issues making getting to loop to work, and was wondering if anyone had any suggestions for it.

Answer 1

[Peter Perkins]

If this is a table in the sense of the table data type, it's even easier:

>> A=array2table([1 2 3;0 4 5;1 8 7;1 14 10;0 1 2;4 1 2;1 2 33])
A = 
    Var1    Var2    Var3
    ____    ____    ____
    1        2       3  
    0        4       5  
    1        8       7  
    1       14      10  
    0        1       2  
    4        1       2  
    1        2      33  
>> varfun(@mean,A,'GroupingVariable','Var1')
ans = 
         Var1    GroupCount    mean_Var2    mean_Var3
         ____    __________    _________    _________
    0    0       2             2.5            3.5    
    1    1       4             6.5          13.25    
    4    4       1               1              2

Answer 2

[Azzi Abdelmalek]

A=[1 2 3;0 4 5;1 8 7;1 14 10;0 1 2;4 1 2;1 2 33]
idx=A(:,1)==1
out=mean(A(idx,[2 3]),2)