topic Re: Can someone explain this piece of code in plain language? in SAS Programming

Can someone explain this piece of code in plain language?

confused_saser — Wed, 25 Jan 2017 17:37:30 GMT

I don't think I understand exactly how this piece of code works:

 if (1 < weekday(date_accident)< 7) then 
       calc_date_accident = date_accident-1; 
    else 
       calc_date_accident = date_accident;

I understand what it is doing-I know that it is subtracting one day from the date_accident variable, but I don't think I understand what is happening in the "IF" statement, specifically the 1 and 7.

Can someone please explain what this code is actually saying?

thanks in advance

Re: Can someone explain this piece of code in plain language?

data_null__ — Wed, 25 Jan 2017 18:02:48 GMT

The expression is a shorthand for

1 < weekday(date_accident) and weekday(date_accident) < 7

you could also say

IF weekday(date_accident) NOT IN (1 7);

Not Saturday or Sunday. See the WEEKDAY() function documentation.

Re: Can someone explain this piece of code in plain language?

confused_saser — Wed, 25 Jan 2017 17:52:56 GMT

thanks @data_null__!

So the 1 and the 7 actually represents Saturday and Sunday?

Does that mean I can select any day of the week by using these numbers in conjuction with "weekday". So for example if I wanted to select Wednesday I would choose the number 4?

Re: Can someone explain this piece of code in plain language?

data_null__ — Wed, 25 Jan 2017 17:56:38 GMT

@confused_saser wrote:

thanks @data_null__!

So the 1 and the 7 actually represents Saturday and Sunday?

Does that mean I can select any day of the week by using these numbers in conjuction with "weekday". So for example if I wanted to select Wednesday I would choose the number 4?

I'm sorry, I assumed you had looked at the documention for the WEEKDAY function and knew what it was returning. Yes today, Wednesday, is weekday 4.

Re: Can someone explain this piece of code in plain language?

confused_saser — Wed, 25 Jan 2017 17:57:06 GMT

I should have looked it up but I actualyl dind't realize it was a function.

Super new to SAS! thank you 🙂

Re: Can someone explain this piece of code in plain language?

data_null__ — Wed, 25 Jan 2017 18:07:16 GMT

@confused_saser wrote:

I should have looked it up but I actualyl dind't realize it was a function.

Super new to SAS! thank you 🙂

I thought your confusion was with the expression 1 < value < 7, it was for me. I had to write an example to make sure I knew what it was doing.

data acc;
   do date_accident = today() to today()+10;
      weekday = weekday(date_accident);
      x = 1 < weekday(date_accident)< 7;
      y = 1 < weekday(date_accident) and weekday(date_accident) < 7;
      z = weekday(date_accident) not in (1 7);
      if (1 < weekday(date_accident)< 7) then calc_date_accident = date_accident-1; 
      else calc_date_accident = date_accident;
      output;
      end;
   run;
proc print;
   run;

Re: Can someone explain this piece of code in plain language?

Peter_C — Wed, 25 Jan 2017 22:22:22 GMT

Thought you might (at cost of a little complexity) have reduced the code to

Calc_date_accident = date_accident - not ( weekday( date_accident ) in( 1, 7 ) ) ;

Since the results of SAS logical operations are either 0 or 1, the composite above achieves what appears to be wanted....

I'm just interested in what activity requires this adjustment for Monday to Friday but not for Saturday and Sunday....?