Get Array Number when value changes - Code does not work

This Code works:

A = {1  'Monday'
2  'Monday'
3  'Monday'
4  'Sunday'
5  'Sunday'
6  'Monday'
7  'Monday'
8  'Friday'};

[a,~,c] = unique(A(:,2),'stable');
i1 = [true;diff(c)~=0];
x = accumarray(cumsum(i1),cell2mat(A(:,1)),[],@(x){[min(x);max(x)]});
y = strcat(A(i1,2),{'_'},arrayfun(@(x)sprintf('%d',x),(1:nnz(i1))','un',0));
Limits = cell2struct(x,y,1);

But when I use numbers in the cell, then it does not work anymore:

A = {1  6
2  6
3  8
4  8
5  8
6  8
7  4
8  4};

[a,~,c] = unique(A(:,2),'stable');
i1 = [true;diff(c)~=0];
x = accumarray(cumsum(i1),cell2mat(A(:,1)),[],@(x){[min(x);max(x)]});
y = strcat(A(i1,2),{'_'},arrayfun(@(x)sprintf('%d',x),(1:nnz(i1))','un',0));
Limits = cell2struct(x,y,1);

Can someone help me please ? :-) Thanks

Answer 1

[Voss]

Three things work differently when you have numbers vs when you have character vectors:

1.) You cannot unique() a cell array of numbers. Make them into a numeric vector first.

2.) Applying strcat() to a number is probably not doing what you want, e.g.:

strcat({6; 8},{'_'},{'1'; '2'})

ans = 2×1 cell array
    {'□_1' }
    {_2'}

In that example, I imagine you'd want:

strcat({'6'; '8'},{'_'},{'1'; '2'})

ans = 2×1 cell array
    {'6_1'}
    {'8_2'}

wherein the conversion from numbers {6; 8} to character vectors {'6'; '8'} can be done by

cellfun(@(x)sprintf('%d',x),A(i1,2),'un',0)

or in R2016b or later by

compose('%d',vertcat(A{i1,2}))

But, 3.) Field names in a struct cannot start with a digit; they have to start with a letter. To fix that, I've prepended 'field_' to each field name.

A = {1  6
2  6
3  8
4  8
5  8
6  8
7  4
8  4};

[a,~,c] = unique(vertcat(A{:,2}),'stable');
i1 = [true;diff(c)~=0];
x = accumarray(cumsum(i1),cell2mat(A(:,1)),[],@(x){[min(x);max(x)]});

% cellfun/sprintf method:
y = strcat('field_',cellfun(@(x)sprintf('%d',x),A(i1,2),'un',0),{'_'},arrayfun(@(x)sprintf('%d',x),(1:nnz(i1))','un',0));

% compose method (R2016b or later):
y = strcat('field_',compose('%d',vertcat(A{i1,2})),{'_'},arrayfun(@(x)sprintf('%d',x),(1:nnz(i1))','un',0));

Limits = cell2struct(x,y,1)

Limits = struct with fields:
    field_6_1: [2×1 double]
    field_8_2: [2×1 double]
    field_4_3: [2×1 double]