Matlab：从索引获取单元格数组的元素

Question

I have a 1x84 cell array that I get the indices for cross validation:

indices = crossvalind('Kfold',length(filenames),k_fold);
for i = 1:k_fold
    test = (indices == i);
    train = ~test;

Given test and train (84x1 logical arrays of 1 or 0) how do I get all filenames that are indexed by test/train?

Answer 1

You could apply logical indexing on the cell array to slice it. Here is simplified example:

%# create a cell array of string
C = cellstr(num2str((1:5)', 'file %d'));

%# random split
trainIdx = rand(size(C)) > 0.5;
testIdx = ~trainIdx;

%# slice cell array
tr = C(trainIdx)
ts = C(testIdx)

Note that both tr and ts are cell arrays of string themselves. So to access the first string in tr , you do:

>> tr{1}