# How can I write all month's last dates for a given period of time?

3 views (last 30 days)
Giorgi on 28 Jan 2015
Commented: Giorgi on 28 Jan 2015
Hello guys. Well I have daily time series form 1990-2015
% code
b=726867;
a=9125;
for i=1:a
b=b+1;
BigMatrix(i,1)=b;
end
BigMatrix=cellstr(datestr(BigMatrix));
Now I want to make another variable where I have only last date of months for a same period of time.

Titus Edelhofer on 28 Jan 2015
Hi,
first of all: you don't need the loop
BigMatrix = b + (1:a);
BigMatrixStr = cellstr(datestr(BigMatrix));
For the last day of a month you have different possibilities. One is to use datevec and note, that the last day of a month is one day before the first of the next month:
% add one day and convert to date vectors:
BigMatrixVec = datevec(BigMatrix+1);
% remove all that are not the first of a month
BigMatrixVec(BigMatrixVec(:,3)~=1, :) = [];
% and subtract that one day again:
BigMatrixStrLast = cellstr(datestr(datenum(BigMatrixVec)-1));
Or use the datetime object that comes with R2014b:
dt = datetime(BigMatrix, 'ConvertFrom', 'datenum');
t = unique(dateshift(dt, 'end', 'month'));
% remove the last month if it's past the last dt
t(t>dt(end)) = [];
Titus
Giorgi on 28 Jan 2015
Well that is really good solution, thank you very much :)

Sean de Wolski on 28 Jan 2015

You could use lbusdate to get the last business day of the month specifying no weekend days:

```weekend = zeros(1,7); % that's depressing :)
```
```web(fullfile(docroot, 'finance/lbusdate.html'))
```

Andrei Bobrov on 28 Jan 2015
BigMatrix = cellstr(datestr(b+(1:a)'));