dates.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}
{* 05apr2005}{...}
{cmd:help dates}
{hline}

{title:Title}

{pstd}
{hi:[U] 24 Dealing with dates}


{title:Remarks}

{pstd}Stata's {cmd:%d} format maps integers onto dates:

{center:    ...                           }
{center:-15,000  corresponds to  01dec1918}
{center:    ...                           }
{center:    -31  corresponds to  01dec1959}
{center:    ...                           }
{center:     -1  corresponds to  31dec1959}
{center:      0  corresponds to  01jan1960}
{center:      1  corresponds to  02jan1960}
{center:    ...                           }
{center:     31  corresponds to  01feb1960}
{center:    ...                           }
{center: 15,000  corresponds to  25jan2001}
{center:    ...                           }

{pstd}
If you subtract two dates (meaning the corresponding integers), you obtain
the number of days between dates:

{center:01feb1960 - 02jan1960 = 31-1 = 30}

{pstd}
Stata provides functions to convert strings containing "01feb1960" or
"February 1, 1960", etc., to dates and other functions to manipulate dates.
See

{p2colset 9 20 22 2}{...}
{p2col :{help datefcn}}Inputting
	dates (translating dates from strings){p_end}
{p2col :{help mdyfcn}}Creating
	dates from month, day, and year{p_end}
{p2col :{help dfcn}}Typing fixed dates in expressions{p_end}
{p2col :{help dexfcns}}Extracting
	month, day, year, etc., from a date{p_end}
{p2col :{help dfmt}}Details of the {cmd:%d} date format{p_end}

{p2col :{help tdates}}Additional
	time-series date formats supported by Stata{p_end}


{pstd}
Note:  after creating a date variable, use the {helpb format} command to
place the {cmd:%d} format on the variable.

	{cmd:. generate mydate =} {it:...}
	{cmd:. format mydate %d}


{title:Also see}

{psee}
Manual:  {bf:[U] 12.5.3 Date formats},{break}
{bf:[U] 24 Dealing with dates},{break}
{bf:[U] 24.2 Dates}

{psee}
Online:  {help tdates};
{helpb format};
{help datefcn},
{help dexfcns},
{help dfcn},
{help dfmt},
{help mdyfcn}
{p_end}