Populating a matrix with the values from array in MATLAB

Question

I have the following arrays,

Names = [string('abc') string('def') string('ghi') string('jkl')]
SubName1 = [string('abc') string('jkl')]
SubValue1 = [-1 1]
SubName2 = [string('ghi') string('jkl')]
SubValue2 = [-2 1]

The array named SubValue1 contains the values that correspond to the keys(strings) in the array named SubName1.I want to compare SubName with Names and create a matrix that maps the key-value pair as follows

RowName  SubName1 SubName2
abc          -1       0
def           0       0 
ghi           0      -2
jkl           1       1

To obtain the above matrix I'm trying the following,

Index1 = find(ismember(Names,SubName1))
Index2 = find(ismember(Names,SubName2))

>>Index1 = [1 4];
>>Index2 = [3 4];

I'm not sure how to proceed from here. Essentially, I am trying to fill the columns of the matrix with the values SubValue of the keysSubNames at the indices present in Index.

Any suggestions?

Paolo · Accepted Answer · 2018-10-14 15:10:38Z

You are almost there. Create empty vectors and use logical indexing with Index1 and Index2 to insert the values from SubValue1 and SubValue2:

>> Names = [string('abc') string('def') string('ghi') string('jkl')];
>> SubName1 = [string('abc') string('jkl')];
>> SubValue1 = [-1 1];
>> SubName2 = [string('ghi') string('jkl')];
>> SubValue2 = [-2 1];

>> Index1 = find(ismember(Names,SubName1))
>> Index2 = find(ismember(Names,SubName2))

>> SubName1 = zeros(numel(Names),1);
>> SubName2 = zeros(numel(Names),1);

>> SubName1(Index1) = SubValue1;
>> SubName2(Index2) = SubValue2;

>> t = table(Names.',SubName1,SubName2);
>> t.Properties.VariableNames(1) = {'RowName'}

t =

  4×3 table

    RowName    SubName1    SubName2
    _______    ________    ________

     "abc"        -1           0   
     "def"         0           0   
     "ghi"         0          -2   
     "jkl"         1           1

Note that the practice of naming variables such as SubName1 and SubName2 is generally discouraged. You mind find this MATLAB answers post useful.

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