gsort -x

*对x做降序排列

你如果用stata的帮助的话，在sort命令的解释里面的最下面的链接里面就有介绍gsort

所以要学会知道一个命令以后，如何查找相关的命令

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help for sort                                                                            manual:  [R] sort
                                                                                         dialog:  sort   
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Sort data

        sort varlist [in range] [, stable]

Description

    sort arranges the observations of the current data in ascending order of the values of the variables
    in varlist.  There is no limit to the number of variables in varlist.  Missing values (see help
    missing) are interpreted as being larger than any other number and thus are placed last, with .
    being placed first followed by .a, .b, ... .z.  (Exception:  When sorting on a string variable, null
    strings are placed first.) The dataset is marked as being sorted by varlist unless in range is
    specified.

    Note: ties in the sort index (i.e., identical sorting values) are broken in an arbitrary (i.e.,
    random) order, unless the stable option is specified.

Option

    stable specifies that observations with the same values of the variables in varlist are to keep
        their same relative order in the sorted data as they had previously.  For instance, consider the
        following data:

                                                   x  b
                                                   3  1
                                                   1  2
                                                   1  1
                                                   1  3
                                                   2  4

        Typing sort x without the stable option produces one of the following 6 orderings.

                            x  b  |  x  b  |  x  b  |  x  b  |  x  b  |  x  b
                            1  2  |  1  2  |  1  1  |  1  1  |  1  3  |  1  3
                            1  1  |  1  3  |  1  2  |  1  3  |  1  1  |  1  2
                            1  3  |  1  1  |  1  3  |  1  2  |  1  2  |  1  1
                            2  4  |  2  4  |  2  4  |  2  4  |  2  4  |  2  4
                            3  1  |  3  1  |  3  1  |  3  1  |  3  1  |  3  1

        Without the stable option, the ordering of observations with equal values of varlist is
        randomized.  With sort x, stable, you will always get the first result and never the other five.

        If your intent was to have the observations sorted first on x and then on b within tied values
        of x (the third result above), you should type sort x b and not sort x, stable.

        stable is rarely of use and, when specified, causes sort to execute more slowly.

Examples

    . sort personid
    . sort lstname frstname midinitl

    . regress y x1 x2 x3
    . predict r, resid
    . sort r
    . list in 1/10
    . list in -10/l

Also see

    Manual:  [R] sort

    Online:  help for describe, gsort