看命令format的help或manual的详细介绍


Title

    [D] format -- Set variables' output format


Syntax

    Set formats

        format varlist %fmt

        format %fmt varlist


    Set style of decimal point

        set dp {comma|period} [, permanently]


    Display long formats

        format [varlist]


    where %fmt can be a numerical, date, business calendar, or string format.

            Numerical
              %fmt            Description              Example
        -------------------------------------------------------
        right-justified
              %#.#g           general                  %9.0g
              %#.#f           fixed                    %9.2f
              %#.#e           exponential              %10.7e
              %21x            hexadecimal              %21x
              %16H            binary, hilo             %16H
              %16L            binary, lohi             %16L
              %8H             binary, hilo             %8H
              %8L             binary, lohi             %8L

        right-justified with commas
              %#.#gc          general                  %9.0gc
              %#.#fc          fixed                    %9.2fc

        right-justified with leading zeros
              %0#.#f          fixed                    %09.2f

        left-justified
              %-#.#g          general                  %-9.0g
              %-#.#f          fixed                    %-9.2f
              %-#.#e          exponential              %-10.7e

        left-justified with commas
              %-#.#gc         general                  %-9.0gc
              %-#.#fc         fixed                    %-9.2fc
        -------------------------------------------------------
        You may substitute comma (,) for period (.) in any of
        the above formats to make comma the decimal point.  In
        %9,2fc, 1000.03 is 1.000,03.  Or you can set dp comma.


              date
              %fmt            Description              Example
        -------------------------------------------------------
        right-justified
              %tc             date/time                %tc
              %tC             date/time                %tC
              %td             date                     %td
              %tw             week                     %tw
              %tm             month                    %tm
              %tq             quarter                  %tq
              %th             half-year                %th
              %ty             year                     %ty
              %tg             generic                  %tg

        left-justified
              %-tc            date/time                %-tc
              %-tC            date/time                %-tC
              %-td            date                     %-td
              etc.
        -------------------------------------------------------
        There are many variations allowed.  See
        [D] datetime display formats.


        business calendar
              %fmt               Description           Example
        -------------------------------------------------------
        %tbcalname               a business calendar  %tbsimple
          [:datetime-specifiers]   defined in
                                   calname.stbcal
        -------------------------------------------------------
        See [D] datetime business calendars.


             string
              %fmt            Description              Example
        -------------------------------------------------------
        right-justified
              %#s             string                   %15s

        left-justified
              %-#s            string                   %-20s

        centered
              %~#s            string                   %~12s
        -------------------------------------------------------
        The centered format is for use with display only.


Menu

    Data > Variables Manager


Description

    format varlist %fmt and format %fmt varlist are the same commands.  They set the display format associated with
    the variables specified.  The default formats are a function of the type of the variable:

                        byte    %8.0g
                        int     %8.0g
                        long    %12.0g
                        float   %9.0g
                        double  %10.0g

                        str#    %#s
                        strL    %9s

    set dp sets the symbol that Stata uses to represent the decimal point.  The default is period, meaning that one
    and a half is displayed as 1.5.

    format [varlist] displays the current formats associated with the variables.  format by itself lists all variables
    that have formats too long to be listed in their entirety by describe. format varlist lists the formats for the
    specified variables regardless of their length. format * lists the formats for all the variables.


Option

    permanently specifies that, in addition to making the change right now, the dp setting be remembered and become
        the default setting when you invoke Stata.


Remarks

    Remarks are presented under the following headings:

        The %f format
        The %fc format
        The %g format
        The %gc format
        The %e format
        The %21x format
        The %16H and %16L formats
        The %8H and %8L formats
        The %t format
        The %s format
        Examples


The %f format

    In %w.df, w is the total output width, including sign and decimal point, and d is the number of digits to appear
    to the right of the decimal point.  The result is right-justified.

    The number 5.139 in %12.2f format displays as

        ----+----1--
                5.14
        

    When d==0, the decimal point is not displayed.  The number 5.14 in %12.0f format displays as

        ----+----1--
                   5

    %-w.df works the same way, except that the output is left-justified in the field.  The number 5.139 in %-12.2f
    displays as

        ----+----1--
        5.14


The %fc format

    %w.dfc works like %w.df except that commas are inserted to make larger numbers more readable.  w records the total
    width of the result, including commas.

    The number 5.139 in %12.2fc format displays as

        ----+----1--
                5.14

    The number 5203.139 in %12.2fc format displays as

        ----+----1--
            5,203.14

    As with %f, if d==0, the decimal point is not displayed.  The number 5203.139 in %12.0fc format displays as

        ----+----1--
               5,203

    As with %f, a minus sign may be inserted to left justify the output.  The number 5203.139 in %-12.0fc format
    displays as

        ----+----1--
        5,203


The %g format

    In %w.dg, w is the overall width, and d is usually specified as 0, which leaves up to the format the number of
    digits to be displayed to the right of the decimal point.  If d!=0 is specified, then not more than d digits will
    be displayed.  As with %f, a minus sign may be inserted to left-justify results.

    %g differs from %f in that (1) it decides how many digits to display to the right of the decimal point, and (2) it
    will switch to a %e format if the number is too large or too small.

    The number 5.139 in %12.0g format displays as

        ----+----1--
               5.139

    The number 5231371222.139 in %12.0g format displays as

        ----+----1--
          5231371222

    The number 52313712223.139 displays as

        ----+----1--
         5.23137e+10

    The number 0.0000029394 displays as

        ----+----1--
         2.93940e-06


The %gc format

    %w.dgc is %w.dg, with commas.  It works in the same way as the %g and %fc formats.


The %e format

    %w.de displays numeric values in exponential format.  w records the width of the format.  d records the number of
    digits to be shown after the decimal place.  w should be greater than or equal to d+7 or, if 3-digit exponents are
    expected, d+8.

    The number 5.139 in %12.4e format is

        ----+----1--
          5.1390e+00

    The number 5.139*10^220 is

        ----+----1--
         5.1390e+220


The %21x format

    The %21x format is for those, typically programmers, who wish to analyze routines for numerical roundoff error.
    There is no better way to look at numbers than how the computer actually records them.

    The number 5.139 in %21x format is

        ----+----1----+----2-
        +1.48e5604189375X+002

    The number 5.125 is

        ----+----1----+----2-
        +1.4800000000000X+002

    Reported is a signed, base-16 number with base-16 point, the letter X, and a signed, 3-digit base-16 integer.
    Call the two numbers f and e.  The interpretation is f*2^e.


The %16H and %16L formats

    The %16H and %16L formats show the value in the IEEE floating point, double-precision form.  %16H shows the value
    in most-significant-byte-first (hilo) form.  %16L shows the number in least-significant-byte-first (lohi) form.

    The number 5.139 in %16H is

        ----+----1----+-
        40148e5604189375

    The number 5.139 in %16L is

        ----+----1----+-
        75931804568e1440

    The format is sometimes used by programmers who are simultaneously studying a hexadecimal dump of a binary file.


The %8H and %8L formats

    %8H and %8L are similar to %16H and %16L but show the number in IEEE single-precision form.

    The number 5.139 in %8H is

        ----+---
        40a472b0

    The number 5.139 in %8L is

        ----+---
        b072a440


The %t format

    The %t format displays numerical variables as dates and times.  See [D] datetime display formats.


The %s format

    The %ws format displays a string in a right-justified field of width w.  %-ws displays the string left-justified.

    "Mary Smith" in %16s format is

        ----+----1----+-
              Mary Smith

    "Mary Smith" in %-16s format is

        ----+----1----+-
        Mary Smith

    In addition, in some contexts, particularly display (see [P] display), %~ws is allowed, which centers the string.
    "Mary Smith" in %~16s format is

        ----+----1----+-
           Mary Smith


Examples

    Four values displayed in different numeric display formats
    +---------------------------------------------------------------------+
    |   %9.0g   %9.0gc     %9.2f     %9.2fc %-9.0g       %09.2f     %9.2e |
    |---------------------------------------------------------------------|
    |   12345   12,345  12345.00  12,345.00  12345    012345.00  1.23e+04 |
    |  37.916   37.916     37.92      37.92  37.916   000037.92  3.79e+01 |
    | 3567890  3567890  3.57e+06   3.57e+06  3567890   3.57e+06  3.57e+06 |
    |   .9165    .9165      0.92       0.92  .9165    000000.92  9.16e-01 |
    +---------------------------------------------------------------------+

    Left-aligned and right-aligned string display formats
    +-------------------------------+
    | %-17s                    %17s |
    |-------------------------------|
    | AMC Concord       AMC Concord |
    | AMC Pacer           AMC Pacer |
    | AMC Spirit         AMC Spirit |
    | Buick Century   Buick Century |
    | Buick Opel         Buick Opel |
    +-------------------------------+


    --------------------------------------------------------------------------------------------------------------------
    Setup
        . webuse census10

    Describe the data
        . describe

    List some of the data
        . list in 1/8

    Left-align the state variable
        . format state %-14s

    List the result
        . list in 1/8

    Left-align region, a numeric variable with attached value label
        . format region %-8.0g

    List the result
        . list in 1/8

    Insert commas in the variable pop
        . format pop %12.0gc

    List the result
        . list in 1/8

    Vertically align the decimal points in medage
        . format medage %8.1f

    List the result
        . list in 1/8

    --------------------------------------------------------------------------------------------------------------------
    Setup
        . webuse fmtxmpl

    List some of the data
        . list empid in 83/87

    Attach leading zeros to empid values
        . format empid %05.0f

    List the result
        . list empid in 83/87

    --------------------------------------------------------------------------------------------------------------------
    Setup
        . webuse fmtxmpl2

    Display the formats of the three date variables
        . format hiredate login logout

    Attach a date format to login and logout
        . format login logout %tcDDmonCCYY_HH:MM:SS.ss

    List the result
        . list login logout in 1/5

    Attach a date format to the hiredate variable
        . format hiredate %td

    List the result
        . list hiredate in 1/5

    Attach a different date format to the hiredate variable
        . format hiredate %tdDD/NN/CCYY

    List the result
        . list hiredate in 1/5

    Display the current formats for all variables using describe
        . describe

    Display the formats for the variables whose display format is too long to show in the describe output
        . format

    --------------------------------------------------------------------------------------------------------------------
    Setup
        . webuse census10

    Attach a European format to the variables pop and medage
        . format pop %12,0gc     (note the comma)
        . format medage %9,2gc

    List the result
        . list in 1/8

    Remove the European format from variables pop and medage
        . format pop %12.0gc      (back to period for the decimal point)
        . format medage %9.2gc

    Change the setting for the decimal point to comma
        . set dp comma

    Perform a one-way tabulation
        . tabulate region [fw=pop]

    Restore period as the setting for the decimal point
        . set dp period
    --------------------------------------------------------------------------------------------

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