How to apply an 'AggregationFunction' with two variables in unstack ?

Question

ALEXANDRE CAZENAVE-LACROUTZ 2020-11-24

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/659973-how-to-apply-an-aggregationfunction-with-two-variables-in-unstack

回答： Campion Loong 2021-2-3

在 MATLAB Online 中打开

Objective:

I would like to get, for each period and group of a timetable, the result of a given function of var1 and var2.

i.e. the ratio of (the sum of var1 over the group) by (the sum of var2 over the group).

using unstack and a function handle: https://www.mathworks.com/help/matlab/ref/unstack.html

Data

A = [1 2 3 4 2 4 6 8]';
B = [4 2 14 7 8 4 28 14]';
C=["group1";"group1";"group2";"group2";"group1";"group1";"group2";"group2"];
Year = [2010 2010 2010 2010 2020 2020 2020 2020]';
Year = datetime(string(Year), 'Format', 'yyyy');
t=table(Year,C,A,B,'VariableNames',{'Year' 'group' 'var1' 'var2'});
t=table2timetable(t,'RowTimes','Year');

function

f = @(x,y) sum(x)./sum(y);   %or f = @(x) sum(x(1,:))./sum(x(2,:));
[Ratio,is] = unstack(t,{'var1','var2'},"group",'AggregationFunction',f);

The types of errors I get:

%Not enough input arguments.
%Or: Index in position 1 exceeds array bounds (must not exceed 1)

Another failed test inspired from https://www.mathworks.com/help/matlab/ref/double.groupsummary.html

(See Method Function Handle with Multiple Inputs)

[Ratio,is] = unstack(t,{["var1"],["var2"]},"group",'AggregationFunction',f);
%Error: A table variable subscript must be a numeric array containing real positive integers, a logical array (...)

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Answer 1

Campion Loong 2021-2-3

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/659973-how-to-apply-an-aggregationfunction-with-two-variables-in-unstack#answer_613942

在 MATLAB Online 中打开

How about this?

>> t_groupsum = groupsummary(t,'group','sum',{'var1','var2'});
>> t_groupsum.Properties.RowNames = t_groupsum.group; % I like the group names as RowLabels
% Ratio of var1 sum between groups
>> t_groupsum.sum_var1("group1")/t_groupsum.sum_var1("group2")
ans =
    0.4286
% Ratio of var2 sum between groups
>> t_groupsum.sum_var2("group1")/t_groupsum.sum_var2("group2")
ans =
    0.2857