Modify the time format of time single value or time variable

[fu gang]

hi , I want to extract the month and day of the current date (c(current_date)) and display them in the format of month and day, occupying two digits respectively. When the month or day is only the ones digit, use zero to fill the digit

date wanted
29 Sep 2021 0929
09 Aug 2021 0809
01 Dec 2021 1201


The codes that I solve the problemto as follows:

scalar M = month(date(c(current_date),"DMY"))
scalar D = day(date(c(current_date),"DMY"))
scalar MD = `=M'`=D' // why it's wring
di "`=M'`=D'" // the result is 929, but i want 0929


Looking forward to your help，thank you very much

[fu gang]

The VBA language in EXCEL can be easily implemented by the following code:
Format(Date, "mmdd")

[Rich Goldstein]

help datetime##s8
help datetime##s4
help datetime_display_formats

[Nick Cox]

. di %tdNNDD daily(c(current_date), "DMY")
0928

[fu gang]

thank you very much , how to quote this month and day(0929), I need to save it as a macro or a scalar and quote it in the code behind

[Leonardo Guizzetti]

One way is to do:

local mydate : di %tdNNDD daily(c(current_date), "DMY")

[fu gang]

thank you very much, the result is 929, but not 0929 i hoped

local mydate : di %tdNNDD daily(c(current_date), "DMY") di `mydate' 929

[Leonardo Guizzetti]

thank you very much, the result is 929, but not 0929 i hoped

local mydate : di %tdNNDD daily(c(current_date), "DMY") di `mydate' 929

That's because when the macro mydate is substituted, it is interpreted as a number, so 0928 becomes 928. Wrap it in quotes to keep the leading zero.

di "`mydate'"

[fu gang]

i got it ,thank you very much

[Nick Cox]

As for

I need to save it as a macro or a scalar

I doubt that is true. The code in e.g. #4 will work fine in a do-file or program, Putting the value in a macro or scalar is not needed unless you need the macro or scalar for some other reason.

[fu gang]

I will often save my documents , adding month and day when naming the document to distinguish the documents

[Nick Cox]

#11 That is good practice to be sure, but code such as

`: di %tdNNDD daily(c(current_date), "DMY")'

can be used on the fly within statements. That's perhaps a little tricksy or unclear, and wanting to use a macro or scalar as a matter of style is one thing, but you don't have to do it that way.

[fu gang]

Thank you very much. It's very kind of you