sort.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}
{* 01dec2004}{...}
{cmd:help sort}{right:dialog:  {bf:{dialog sort}}}
{hline}

{title:Title}

{p2colset 5 17 19 2}{...}
{p2col :{hi:[D] sort} {hline 2}}Sort data{p_end}
{p2colreset}{...}


{title:Syntax}

{p 8 13 2}
{opt so:rt}
{varlist}
[{it:{help in}}]
[{cmd:,} {opt stable}]


{title:Description}

{pstd}
{opt sort} arranges the observations of the current data into ascending order
based on the values of the variables in {varlist}.  There is no limit to the
number of variables in the {it:varlist}.  Missing numeric values (see 
{help missing}) are interpreted as being larger than any other number, so they
are placed last with {cmd:. < .a < .b ... < .z}.  When you sort on a string
variable, however, null strings are placed first.  The dataset is marked as
being sorted by {it:varlist} unless {help in:{bf:in} {it:range}} is specified.
If {opt in} {it:range} is specified, only those observations are rearranged.
The unspecified observations remain in the same place.


{title:Option}

{phang}
{opt stable} specifies that observations with the same values of the variables
in {varlist} keep the same relative order in the sorted data that
they had previously.  For instance, consider the following data:

{center:x  b}
{center:3  1}
{center:1  2}
{center:1  1}
{center:1  3}
{center:2  4}

{pmore}
Typing {cmd:sort x} without the {opt stable} option produces one of the
following 6 orderings.

{center:x  b  {c |}  x  b  {c |}  x  b  {c |}  x  b  {c |}  x  b  {c |}  x  b}
{center:1  2  {c |}  1  2  {c |}  1  1  {c |}  1  1  {c |}  1  3  {c |}  1  3}
{center:1  1  {c |}  1  3  {c |}  1  3  {c |}  1  2  {c |}  1  1  {c |}  1  2}
{center:1  3  {c |}  1  1  {c |}  1  3  {c |}  1  2  {c |}  1  2  {c |}  1  1}
{center:2  4  {c |}  2  4  {c |}  2  4  {c |}  2  4  {c |}  2  4  {c |}  2  4}
{center:3  1  {c |}  3  1  {c |}  3  1  {c |}  3  1  {c |}  3  1  {c |}  3  1}

{pmore}
Without the {opt stable} option, the ordering of observations with equal
values of {it:varlist} is randomized.  With {cmd:sort x, stable}, you will
always get the first ordering and never the other five.

{pmore}
If your intent is to have the observations sorted first on {opt x} and then
on {opt b} within tied values of {opt x} (the third ordering above), you should
type {opt sort x b} rather than {opt sort x, stable}.

{pmore}
{opt stable} is seldom used, and, when specified, causes {opt sort} to
execute more slowly.


{title:Examples}

{phang}{cmd:. sort person id}{p_end}
{phang}{cmd:. sort lstname frstname midinitl}{p_end}

{phang}{cmd:. regress y x1 x2 x3}{p_end}
{phang}{cmd:. predict r, resid}{p_end}
{phang}{cmd:. sort r}{p_end}
{phang}{cmd:. list in 1/10}{p_end}
{phang}{cmd:. list in -10/l}{p_end}


{title:Also see}

{psee}
Manual:  {bf:[D] sort}

{psee}
Online:  {helpb describe},
{helpb gsort}
{p_end}