insert datetime in array

how can i insert datetime in the datetime array?

Example: insert 2008-03-28 in array

result: 2008-01-05 2008-02-02 2008-03-01 2008-03-28 2008-04-05 ........

Answer 1

[Voss]

I assume the array is sorted and needs to remain sorted after inserting the new element.

One easy way is to concatenate the new element with the array and then sort that new array:

% a datetime array:
fmt = 'uuuu-MM-dd';
dt_array = datetime({'2008-01-05','2008-02-02','2008-03-01','2008-04-05'},'InputFormat',fmt)

dt_array = 1×4 datetime array
   05-Jan-2008   02-Feb-2008   01-Mar-2008   05-Apr-2008

% a datetime scalar:
new_dt = datetime('2008-03-28','InputFormat',fmt)

new_dt = datetime
   28-Mar-2008

% concatenate and sort:
dt_array = sort([dt_array new_dt])

dt_array = 1×5 datetime array
   05-Jan-2008   02-Feb-2008   01-Mar-2008   28-Mar-2008   05-Apr-2008

[Voss]

Another more involved way is to find where the new element belongs in the array and insert it there:

% a datetime array:
fmt = 'uuuu-MM-dd';
dt_array = datetime({'2008-01-05','2008-02-02','2008-03-01','2008-04-05'},'InputFormat',fmt)

dt_array = 1×4 datetime array
   05-Jan-2008   02-Feb-2008   01-Mar-2008   05-Apr-2008

% a datetime scalar:
new_dt = datetime('2008-03-28','InputFormat',fmt)

new_dt = datetime
   28-Mar-2008

% make sure the array is sorted
if ~issorted(dt_array)
    % and sort it if not
    dt_array = sort(dt_array);
end

% find the index of the first element of dt_array later than new_dt
idx = find(dt_array > new_dt, 1);

% if there are no elements later than new_dt
if isempty(idx)
    % then new_dt goes on the end
    idx = numel(dt_array)+1;
end

% insert dt_new at index idx in dt_array
dt_array = [dt_array(1:idx-1) new_dt dt_array(idx:end)]

dt_array = 1×5 datetime array
   05-Jan-2008   02-Feb-2008   01-Mar-2008   28-Mar-2008   05-Apr-2008