Create a monthly datetime sequence

Hello everyone,

Can someone please me explain why this code

a=datetime(1981,1,1);

b=datetime(2019,31,1);

t1=a:calmonths(1):b;

t2=datetime(t1,'Format','yyyy-M-d');

M=datevec(t2);

Gives me monthly dates until july 2021? Am I missing something?

Thank you!

[Stephen23]

t1.Format = 'yyyy-M-d' % the correct way to set the format.

t1 = 1×457 datetime array
   1981-1-1    1981-2-1    1981-3-1    1981-4-1    1981-5-1    1981-6-1    1981-7-1    1981-8-1    1981-9-1    1981-10-1   1981-11-1   1981-12-1   1982-1-1    1982-2-1    1982-3-1    1982-4-1    1982-5-1    1982-6-1    1982-7-1    1982-8-1    1982-9-1    1982-10-1   1982-11-1   1982-12-1   1983-1-1    1983-2-1    1983-3-1    1983-4-1    1983-5-1    1983-6-1    1983-7-1    1983-8-1    1983-9-1    1983-10-1   1983-11-1   1983-12-1   1984-1-1    1984-2-1    1984-3-1    1984-4-1    1984-5-1    1984-6-1    1984-7-1    1984-8-1    1984-9-1    1984-10-1   1984-11-1   1984-12-1   1985-1-1    1985-2-1    1985-3-1    1985-4-1    1985-5-1    1985-6-1    1985-7-1    1985-8-1    1985-9-1    1985-10-1   1985-11-1   1985-12-1   1986-1-1    1986-2-1    1986-3-1    1986-4-1    1986-5-1    1986-6-1    1986-7-1    1986-8-1    1986-9-1    1986-10-1   1986-11-1   1986-12-1   1987-1-1    1987-2-1    1987-3-1    1987-4-1    1987-5-1    1987-6-1    1987-7-1    1987-8-1    1987-9-1    1987-10-1   1987-11-1   1987-12-1   1988-1-1    1988-2-1    1988-3-1    1988-4-1    1988-5-1    1988-6-1    1988-7-1    1988-8-1    1988-9-1    1988-10-1   1988-11-1   1988-12-1   1989-1-1    1989-2-1    1989-3-1    1989-4-1    1989-5-1    1989-6-1    1989-7-1    1989-8-1    1989-9-1    1989-10-1   1989-11-1   1989-12-1   1990-1-1    1990-2-1    1990-3-1    1990-4-1    1990-5-1    1990-6-1    1990-7-1    1990-8-1    1990-9-1    1990-10-1   1990-11-1   1990-12-1   1991-1-1    1991-2-1    1991-3-1    1991-4-1    1991-5-1    1991-6-1    1991-7-1    1991-8-1    1991-9-1    1991-10-1   1991-11-1   1991-12-1   1992-1-1    1992-2-1    1992-3-1    1992-4-1    1992-5-1    1992-6-1    1992-7-1    1992-8-1    1992-9-1    1992-10-1   1992-11-1   1992-12-1   1993-1-1    1993-2-1    1993-3-1    1993-4-1    1993-5-1    1993-6-1    1993-7-1    1993-8-1    1993-9-1    1993-10-1   1993-11-1   1993-12-1   1994-1-1    1994-2-1    1994-3-1    1994-4-1    1994-5-1    1994-6-1    1994-7-1    1994-8-1    1994-9-1    1994-10-1   1994-11-1   1994-12-1   1995-1-1    1995-2-1    1995-3-1    1995-4-1    1995-5-1    1995-6-1    1995-7-1    1995-8-1    1995-9-1    1995-10-1   1995-11-1   1995-12-1   1996-1-1    1996-2-1    1996-3-1    1996-4-1    1996-5-1    1996-6-1    1996-7-1    1996-8-1    1996-9-1    1996-10-1   1996-11-1   1996-12-1   1997-1-1    1997-2-1    1997-3-1    1997-4-1    1997-5-1    1997-6-1    1997-7-1    1997-8-1    1997-9-1    1997-10-1   1997-11-1   1997-12-1   1998-1-1    1998-2-1    1998-3-1    1998-4-1    1998-5-1    1998-6-1    1998-7-1    1998-8-1    1998-9-1    1998-10-1   1998-11-1   1998-12-1   1999-1-1    1999-2-1    1999-3-1    1999-4-1    1999-5-1    1999-6-1    1999-7-1    1999-8-1    1999-9-1    1999-10-1   1999-11-1   1999-12-1   2000-1-1    2000-2-1    2000-3-1    2000-4-1    2000-5-1    2000-6-1    2000-7-1    2000-8-1    2000-9-1    2000-10-1   2000-11-1   2000-12-1   2001-1-1    2001-2-1    2001-3-1    2001-4-1    2001-5-1    2001-6-1    2001-7-1    2001-8-1    2001-9-1    2001-10-1   2001-11-1   2001-12-1   2002-1-1    2002-2-1    2002-3-1    2002-4-1    2002-5-1    2002-6-1    2002-7-1    2002-8-1    2002-9-1    2002-10-1   2002-11-1   2002-12-1   2003-1-1    2003-2-1    2003-3-1    2003-4-1    2003-5-1    2003-6-1    2003-7-1    2003-8-1    2003-9-1    2003-10-1   2003-11-1   2003-12-1   2004-1-1    2004-2-1    2004-3-1    2004-4-1    2004-5-1    2004-6-1    2004-7-1    2004-8-1    2004-9-1    2004-10-1   2004-11-1   2004-12-1   2005-1-1    2005-2-1    2005-3-1    2005-4-1    2005-5-1    2005-6-1    2005-7-1    2005-8-1    2005-9-1    2005-10-1   2005-11-1   2005-12-1   2006-1-1    2006-2-1    2006-3-1    2006-4-1    2006-5-1    2006-6-1    2006-7-1    2006-8-1    2006-9-1    2006-10-1   2006-11-1   2006-12-1   2007-1-1    2007-2-1    2007-3-1    2007-4-1    2007-5-1    2007-6-1    2007-7-1    2007-8-1    2007-9-1    2007-10-1   2007-11-1   2007-12-1   2008-1-1    2008-2-1    2008-3-1    2008-4-1    2008-5-1    2008-6-1    2008-7-1    2008-8-1    2008-9-1    2008-10-1   2008-11-1   2008-12-1   2009-1-1    2009-2-1    2009-3-1    2009-4-1    2009-5-1    2009-6-1    2009-7-1    2009-8-1    2009-9-1    2009-10-1   2009-11-1   2009-12-1   2010-1-1    2010-2-1    2010-3-1    2010-4-1    2010-5-1    2010-6-1    2010-7-1    2010-8-1    2010-9-1    2010-10-1   2010-11-1   2010-12-1   2011-1-1    2011-2-1    2011-3-1    2011-4-1    2011-5-1    2011-6-1    2011-7-1    2011-8-1    2011-9-1    2011-10-1   2011-11-1   2011-12-1   2012-1-1    2012-2-1    2012-3-1    2012-4-1    2012-5-1    2012-6-1    2012-7-1    2012-8-1    2012-9-1    2012-10-1   2012-11-1   2012-12-1   2013-1-1    2013-2-1    2013-3-1    2013-4-1    2013-5-1    2013-6-1    2013-7-1    2013-8-1    2013-9-1    2013-10-1   2013-11-1   2013-12-1   2014-1-1    2014-2-1    2014-3-1    2014-4-1    2014-5-1    2014-6-1    2014-7-1    2014-8-1    2014-9-1    2014-10-1   2014-11-1   2014-12-1   2015-1-1    2015-2-1    2015-3-1    2015-4-1    2015-5-1    2015-6-1    2015-7-1    2015-8-1    2015-9-1    2015-10-1   2015-11-1   2015-12-1   2016-1-1    2016-2-1    2016-3-1    2016-4-1    2016-5-1    2016-6-1    2016-7-1    2016-8-1    2016-9-1    2016-10-1   2016-11-1   2016-12-1   2017-1-1    2017-2-1    2017-3-1    2017-4-1    2017-5-1    2017-6-1    2017-7-1    2017-8-1    2017-9-1    2017-10-1   2017-11-1   2017-12-1   2018-1-1    2018-2-1    2018-3-1    2018-4-1    2018-5-1    2018-6-1    2018-7-1    2018-8-1    2018-9-1    2018-10-1   2018-11-1   2018-12-1   2019-1-1 

Answer 1

[David Hill]

a=datetime(1981,1,1);
b=datetime(2019,1,31);%must be year,month,day
t1=a:calmonths(1):b;
t2=datetime(t1,'Format','yyyy-M-d');
M=datevec(t2);

[Enrico Gambini]

Omg i'm so stupid.... Thank you....