How to conditionally merge rows in a table

Hi,

I have a quick question - I have the following table T and I would like to merge the rows where the values of the variables lat, lon and id are identical and where only the values of the key variable are different. The desired output is shown.

lat = [45.67, 45.67, 56.89, 78.61]';
lon = [-66.45, -66.45, -65, -67]';
id = [202, 202, 201, 200]';
key = {'A', 'B', 'C', 'C'}';
T = table(lat, lon, id, key)

[C, ia, ic] = unique(T(:, 1:3),'rows')

% desired output:
lat = [45.67, 56.89, 78.61]';
lon = [-66.45, -65, -67]';
id = [202, 201, 200]';
key = {'A, B', 'C', 'C'}';
desired_output = table(lat, lon, id, key)

Thank you,

Answer 1

[Stephen Cobeldick]

lat = [45.67, 45.67, 56.89, 78.61]';
lon = [-66.45, -66.45, -65, -67]';
id = [202, 202, 201, 200]';
key = {'A', 'B', 'C', 'C'}';
T = table(lat, lon, id, key)

T = 4x4 table
     lat      lon      id      key 
    _____    ______    ___    _____

    45.67    -66.45    202    {'A'}
    45.67    -66.45    202    {'B'}
    56.89       -65    201    {'C'}
    78.61       -67    200    {'C'}

[C, ia, ic] = unique(T(:, 1:3),'rows');
C.key = splitapply(@(s)join(s,', '),T.key,ic)

C = 3x4 table
     lat      lon      id       key   
    _____    ______    ___    ________

    45.67    -66.45    202    {'A, B'}
    56.89       -65    201    {'C'   }
    78.61       -67    200    {'C'   }