Convert time with a 12 hrs setting, to 24 hrs

[Aurora Casadei]

Dear all,

I have to convert a variable setting in "12 hours" to "24 hours". I divided the variable into v2= "time" and v3="AM/PM", and then added 12hours if v3 == "PM", but this creates a problem for the 12PM, that are converted to midnight.

The code:

The output:

I'd be grateful for any advice, thank you in advance,

Aurora

[William Lisowski]

You do not want to add 12 hours to 12PM: hours 0-11 are AM and hours 12-23 are PM.

* Example generated by -dataex-. For more info, type help dataex
clear
input str8 v2 str2 v3
"12:40:49" "PM"
"1:20:42"  "PM"
end

gen double time_part = clock(v2, "hms")
format time_part %tcHH:MM:SS
replace time_part = time_part + 12*60*60*1000 if v3=="PM" & hh(time_part)<12
list, clean abbreviate(12)

. list, clean abbreviate(12)

             v2   v3   time_part  
  1.   12:40:49   PM    12:40:49  
  2.    1:20:42   PM    13:20:42

[Nick Cox]

I have seen the equivalent of "12:30" or "24:30" in raw data for times in the first hour after midnight, sometimes systematically so.

The first is, in effect, what my watch tells me too.

An ad hoc fix to the data is I think the only serious option. .