Stata 15 help for datetime_display_formats

[D] datetime display formats -- Display formats for dates and times

Syntax

The formats for displaying Stata internal form (SIF) dates and times in human readable form (HRF) are

Display format to SIF type present SIF in HRF ------------------------------------- datetime/c %tc[details] datetime/C %tC[details]

date %td[details]

weekly date %tw[details] monthly date %tm[details] quarterly date %tq[details] half-yearly date %th[details] yearly date %ty[details] -------------------------------------

The optional details allows you to control how results appear and is composed of a sequence of the following codes:

Code Meaning Output ----------------------------------------------------------------- CC century-1 01 - 99 cc century-1 1 - 99 YY 2-digit year 00 - 99 yy 2-digit year 0 - 99

JJJ day within year 001 - 366 jjj day within year 1 - 366

Mon month Jan, Feb, ..., Dec Month month January, February, ..., December mon month jan, feb, ..., dec month month january, february, ..., december NN month 01 - 12 nn month 1 - 12

DD day within month 01 - 31 dd day within month 1 - 31

DAYNAME day of week Sunday, Monday, ... (aligned) Dayname day of week Sunday, Monday, ... (unaligned) Day day of week Sun, Mon, ... Da day of week Su, Mo, ... day day of week sun, mon, ... da day of week su, mo, ...

h half 1 - 2 q quarter 1 - 4 WW week 01 - 52 ww week 1 - 52

HH hour 00 - 23 Hh hour 00 - 12 hH hour 0 - 23 hh hour 0 - 12

MM minute 00 - 59 mm minute 0 - 59

SS second 00 - 60 (sic, due to leap seconds) ss second 0 - 60 (sic, due to leap seconds) .s tenths .0 - .9 .ss hundredths .00 - .99 .sss thousandths .000 - .999

am show am or pm am or pm a.m. show a.m. or p.m. a.m. or p.m. AM show AM or PM AM or PM A.M. show A.M. or P.M. A.M. or P.M.

. display period . , display comma , : display colon : - display hyphen - _ display space / display slash / \ display backslash \ !c display character c

+ separator (see note) ----------------------------------------------------------------- Note: + displays nothing; it may be used to separate one code from the next to make the format more readable. + is never necessary. For instance, %tchh:MM+am and %tchh:MMam have the same meaning, as does %tc+hh+:+MM+am.

When details is not specified, it is equivalent to specifying

Format | Implied (fully specified) format -------+--------------------------------- %tC | %tCDDmonCCYY_HH:MM:SS %tc | %tcDDmonCCYY_HH:MM:SS | %td | %tdDDmonCCYY | %tw | %twCCYY!www %tm | %tmCCYY!mnn %tq | %tqCCYY!qq %th | %thCCYY!hh %ty | %tyCCYY -----------------------------------------

That is, typing

. format mytimevar %tc

has the same effect as typing

. format mytimevar %tcDDmonCCYY_HH:MM:SS

Format %tcDDmonCCYY_HH:MM:SS is interpreted as

+---------------------------------------------------------------+ | % t c DDmonCCYY_HH:MM:SS | | | | | | | | all formats it is a variable formatting codes | | start with % datetime coded in specify how to | | format milliseconds display value | +---------------------------------------------------------------+

Description

Stata stores dates and times numerically in one of the eight SIFs. An SIF might be 18,282 or even 1,579,619,730,000. Place the appropriate format on it, and the 18,282 is displayed as 20jan2010 (%td). The 1,579,619,730,000 is displayed as 20jan2010 15:15:30 (%tc).

If you specify additional format characters, you can change how the result is displayed. Rather than 20jan2010, you could change it to 2010.01.20; January 20, 2010; or 1/20/10. Rather than 20jan2010 15:15:30, you could change it to 2010.01.20 15:15; January 20, 2010 3:15 pm; or Wed Jan 20 15:15:30 2010.

See [D] datetime for an introduction to Stata's dates and times.

Remarks

Remarks are presented under the following headings:

Specifying display formats Times are truncated, not rounded, when displayed

Specifying display formats

Rather than using the default format 20jan2010, you could display the SIF date variable in one of these formats:

2010.01.20 January 20, 2010 1/20/10

Likewise, rather than displaying the SIF datetime/c variable in the default format 20jan2010 15:15:30, you could display it in one of these formats:

2010.01.20 15:15 January 20, 2010 3:15 pm Wed Jan 20 15:15:30 2010

Here is how to do it:

1. 2010.01.20 format mytdvar %tdCCYY.NN.DD

2. January 20, 2010 format mytdvar %tdMonth_dd,_CCYY

3. 1/20/10 format mytdvar %tdnn/dd/YY

4. 2010.01.20 15:15 format mytcvar %tcCCYY.NN.DD_HH:MM

5. January 20, 2010 3:15 pm format mytcvar %tcMonth_dd,_CCYY_hh:MM_am Code am at the end indicates that am or pm should be displayed, as appropriate.

6. Wed Jan 20 15:15:30 2010 format mytcvar %tcDay_Mon_DD_HH:MM:SS_CCYY

In examples 1 to 3, the formats each begin with %td, and in examples 4 to 6, the formats begin with %tc. It is important that you specify the opening correctly -- namely, as % + t + third_character. The third character indicates the particular SIF encoding type, which is to say, how the numeric value is to be interpreted. You specify %tc... for datetime/c variables, %tC... for datetime/C, %td... for date, and so on.

The default format for datetime/c and datetime/C variables omits the fraction of seconds; 15:15:30.000 is displayed as 15:15:30. If you wish to see the fractional seconds, specify the format

%tcDDmonCCYY_HH:MM:SS.sss or %tCDDmonCCYY_HH:MM:SS.sss

as appropriate.

Times are truncated, not rounded, when displayed

Consider the time 11:32:59.999. Other, less precise, ways of writing that time are

11:32:59.99 11:32:59.9 11:32:59 11:32

That is, when you suppress the display of more-detailed components of the time, the parts that are displayed are not rounded. Stata displays time just as a digital clock would; the time is 11:32 right up until the instant that it becomes 11:33.


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