Time format reshuffle

[peter peter]

I've downloaded a file which has the American M/D/Y format:
Date
1/27/2018
1/28/2018
….
And I’d like to convert that into
Date
27-jan-2018
28-jan-2018
…
Can anyone help?

[Clyde Schechter]

I've downloaded a file which has the American M/D/Y format:

Unfortunately, all you are describing is how this looks to your eyes when you view the data somewhere, perhaps the Browser, or a -list- output. But to properly answer your question we need to also know how this data is represented internally: is it a string variable that looks the way you show it, or is it a Stata internal format daily date variable with a display format that produces what you see attached to it? Or is it possibly a Stata internal format clock variable which has been formatted to suppress the time components?

On the hunch that it's a Stata internal format date variable that is formatted %tdnn/dd/CCYY or perhaps %tdnn/DD/CCYY (either of these would be consistent with what you show, although they would handle a date like 1 jan 2018 differently), all you need to do is:

format Date %tdNN-mon-CCYY

However, if your variable Date is actually a string, then you would first be best advised to convert it to a Stata internal format date variable:

gen _Date = daily(Date, "MDY")
assert missing(_Date) == missing(Date)
format _Date %tdNN-mon-CCYY
drop Date
rename _Date Date

And, finally, if it is actually a Stata internal format clock variable:

gen _Date = dofc(Date)
format _Date %tdNN-mon-CCYY
rename Date DateTime
rename _Date Date

In the future to avoid guesswork, always show example data when asking for help with coding. It is usually the case that correct code depends on the details of the data that cannot be adequately conveyed with verbal descriptions or visual displays. So always use the -dataex- command to share the example data on the Forum. If you are running version 18, 17, 16 or a fully updated version 15.1 or 14.2, -dataex- is already part of your official Stata installation. If not, run -ssc install dataex- to get it. Either way, run -help dataex- to read the simple instructions for using it. -dataex- will save you time; it is easier and quicker than typing out tables. It includes complete information about aspects of the data that are often critical to answering your question but cannot be seen from tabular displays or screenshots. It also makes it possible for those who want to help you to create a faithful representation of your example to try out their code, which in turn makes it more likely that their answer will actually work in your data.

[peter peter]

Thanks Clyde. sorry indeed for my terse posting. Indeed, it's string data and in the MMDDYY format rather than my desired DD-MM-YY format.
What you suggested makes sense but doesn't quite seem to do the trick (assuming I've implemented it correctly). see below

de date symbol

storage display value
variable name type format label variable label
----------------------------------------------------------------------------------------------------------------
date str10 %10s
symbol str5 %9s


li date symbol in 1/35

+--------------------+
| date symbol |
|--------------------|
1. | 1/1/2018 BAC |
2. | 1/2/2018 BAC |
<snip>
29. | 1/29/2018 BAC |
30. | 1/30/2018 BAC |
|--------------------|
31. | 1/31/2018 BAC |
32. | 2/1/2018 BAC |
33. | 2/2/2018 BAC |
34. | 2/3/2018 BAC |
35. | 2/4/2018 BAC |
+--------------------+

. gen _Date = daily(date, "MDY")
. assert missing(_Date) == missing(date)
. format _Date %tdNN-mon-CCYY
. drop date
. rename _Date Date

. li Date symbol in 1/35

+----------------------+
| Date symbol |
|----------------------|
1. | 01-jan-2018 BAC |
2. | 01-jan-2018 BAC |
<snip>
29. | 01-jan-2018 BAC |
30. | 01-jan-2018 BAC |
|----------------------|
31. | 01-jan-2018 BAC |
32. | 02-feb-2018 BAC |
33. | 02-feb-2018 BAC |
34. | 02-feb-2018 BAC |
35. | 02-feb-2018 BAC |
+----------------------+

[Clyde Schechter]

What you suggested makes sense but doesn't quite seem to do the trick (assuming I've implemented it correctly). see below

Sorry, my error. The correct display format for what you want is %tdDD-mon-CCYY.

[peter peter]

Many thanks Clyde.