Formatting Time in HH:MM:SS.sss into a if-then statement?

[Tbaso]

Im using SAS 3.7 (Enterprise Edition)

The time a dataset I am using has the time in military time with a format of 00:00:00.000

I am trying to format the Time in my data set into sections such as 6am-12pm = morning.

I run into this error when I run my code, 

71         Data TimeofDay;
 72             set Airplane ;
 73         
 74             If  00:00:00.000 <= Time <= 06:00:00.000 then Time= 'Night';
                      _
                      388
                      76
 75             If  06:00:00.000 <= Time <= 12:00:00.000 then Time= 'Morning';
                      _
                      388
                      76
 76             If  12:00:00.000 <= Time <= 18:00:00.000 then Time= 'Afternoon';
                      _
                      388
                      76
 77             If  18:00:00.000 <= Time <= 24:00:00.000 then Time= 'Evening';
                      _
                      388
                      76
 ERROR 388-185: Expecting an arithmetic operator.
 
 ERROR 76-322: Syntax error, statement will be ignored.

 

Here is my code:

Data TimeofDay;
    set Airplane ;
    If  00:00:00.000 <= Time <= 06:00:00.000 then Time= 'Night'; 
    If  06:00:00.000 <= Time <= 12:00:00.000 then Time= 'Morning'; 
    If  12:00:00.000 <= Time <= 18:00:00.000 then Time= 'Afternoon'; 
    If  18:00:00.000 <= Time <= 24:00:00.000 then Time= 'Evening'; 
    Run;

My question is how do I format the time in the if then statement in order to not run into this error?

I've been reading solutions from other people but nothing has worked for me. 

I would be grateful for any response.

[LaurieF · Accepted solution]

SAS is very simply typed. It knows about character and numeric fields. The simple replacement for your first statement would be:

 If '00:00:00.000't <= Time <= '06:00:00.000't then Time= 'Night';

But that won't do what you want. Note, for example that if the time is exactly 6am, your next statement will override it with Morning. But that isn't right either! Because you've already implicitly defined Time as being 5 characters long (Night), it'll be Morni. But that won't work either, because you've already defined Time as numeric. So you need a new variable.

Here's how I would recommend you re-write it.

Data TimeofDay;
 set Airplane;
 length Timename $ 9;
 select;
    when('00:00:00't <= Time < '6:00:00't) Timename= 'Night';
    when('06:00:00't <= Time < '12:00:00't) Timename= 'Morning';
    when('12:00:00't <= Time < '18:00:00't) Timename= 'Afternoon';
    otherwise Timename = 'Evening';
    end;
run;

[Tbaso]

Thank you so much for your response! Great explanation.