tfcn.hlp

是一个经济学管理应用软件 很难找的 但是经济学学生又必须用到

{smcl}
{* 07apr2005}{...}
{cmd:help tfcn}
{hline}

{title:Title}

{pstd}
{hi:[U] 24.3.2 Specifying particular dates (date literals)}


{title:Syntax}

{p 8 24 2}{it:...} {cmd:d(}{it:constant}{cmd:)} {it:...} {space 4} returns {cmd:%td} date{p_end}
{p 8 24 2}{it:...} {cmd:w(}{it:constant}{cmd:)} {it:...} {space 4} returns {cmd:%tw} date{p_end}
{p 8 24 2}{it:...} {cmd:m(}{it:constant}{cmd:)} {it:...} {space 4} returns {cmd:%tm} date{p_end}
{p 8 24 2}{it:...} {cmd:q(}{it:constant}{cmd:)} {it:...} {space 4} returns {cmd:%tq} date{p_end}
{p 8 24 2}{it:...} {cmd:h(}{it:constant}{cmd:)} {it:...} {space 4} returns {cmd:%th} date{p_end}
{p 8 24 2}{it:...} {cmd:y(}{it:constant}{cmd:)} {it:...} {space 4} returns {cmd:%ty} date{p_end}


    Function description:

{p 4 25 2}Argument:{space 2}{cmd:d()}:{space 2}a day followed by a month followed by a 4-digit year{p_end}
{p 15 25 2}{cmd:w()}:{space 2}a 4-digit year followed by a week number, 1-52.{p_end}
{p 15 25 2}{cmd:m()}:{space 2}a 4-digit year followed by a month number, 1-12.{p_end}
{p 15 25 2}{cmd:q()}:{space 2}a 4-digit year followed by a quarter number, 1-4.{p_end}
{p 15 25 2}{cmd:h()}:{space 2}a 4-digit year followed by a half number, 1 or 2.{p_end}
{p 15 25 2}{cmd:y()}:{space 2}a 4-digit year{p_end}
{pstd}Returns:{space 3}as shown above

{p 4 11 2}Note:  When typing one number followed by another, you must
place some separator between them, which may be comma, colon, dash, or even
a word or phrase.  That is, you cannot type {cmd:w(1999 5)}; you may type
{cmd:w(1995w5)} or {cmd:w(1995 w 5)} or {cmd:w(1995 week number 5)}.

{p 4 11 2}Note:  The {cmd:y()} function is often omitted since, for instance,
{cmd:y(1980)}==1980.  However, {cmd:y()} does verify the argument has the
interpretation of a 4-digit year; {cmd:y(80)} is an error.

{pstd}
See {help tdates} for an explanation of {cmd:%t} time-series dates.
See {help tfmt} for an explanation of time-series formats.


{title:Examples}

{phang2}{cmd:. regress} {it:...} {cmd:if hdate > d(1mar1998)}

{pstd}
All of the following are equivalent

{phang2}{cmd:. tabulate} {it:...} {cmd:if bdate > d(15 january 1980)}{p_end}
{phang2}{cmd:. tabulate} {it:...} {cmd:if bdate > d(15january1980)}{p_end}
{phang2}{cmd:. tabulate} {it:...} {cmd:if bdate > d(15jan1980)}{p_end}
{phang2}{cmd:. tabulate} {it:...} {cmd:if bdate > d(15Jan1980)}{p_end}
{phang2}{cmd:. tabulate} {it:...} {cmd:if bdate > d(15/1/1980)}{p_end}
{phang2}{cmd:. tabulate} {it:...} {cmd:if bdate > d(15,1,1980)}
	...

{pstd}
but typing {cmd:tabulate} {it:...} {cmd:if bdate > d(15 1 1980)} would be
an error.


{phang2}{cmd:. logistic} {it:...} {cmd:if qdate > q(1990-2)}

{phang2}{cmd:. count} {it:...} {cmd:if wdate < q(1990.1)}


{title:Also see}

{psee}
Manual:  {bf:[D] functions},{break}
{bf:[U] 24 Dealing with dates},{break}
{bf:[U] 24.3.2 Specifying particular dates (date literals)}

{psee}
Online:  {help tdates},
{help tfmt};
{help dates},
{help dfcn},
{helpb format},
{help functions},
{help mdyfcn}
{p_end}