Using IF-ELSE-IF statement to create new date variable

[yiyizhao86]

Hi! I have an original dataset as the following:

id      start_date       end_date 

1      2016-06-01     2016-07-01

2      2013-02-01     2014-04-06

2      2015-01-03     2016-03-07

3      2013-01-01     2015-03-06

For each row, I would like to compute the days between the start date and the end date that is between year 2014-01-01 to 2014-12-31.

I was thinking that I can create two new variables per row so that:

id      start_date       end_date        date1                date2         

1      2016-06-01     2016-07-01      .                         .

2      2013-02-01     2014-04-06     2014-01-01    2014-04-06

2      2015-01-03     2016-03-07     .                         .

3      2013-01-01     2015-03-06     2014-01-01     2014-12-31

and then I can drop the rows with missing value and compute the difference between date2 and date1. But the following code does not work:

data want;

        set original;

        format date1 date2 YYMMDD10.;

        if start_date <= 2004-01-01 then date1 = 2004-01-01;

           else if start_date <= 2004-12-31 then date1 = start_date;

           else date1 = .;

        if end_date < 2004-01-01 then date2 =.;

           else if end_date <= 2004-12-31 then date2 = end_date;

           else date2 = 2004-12-31;

run;

Could you please help me fixing the above code or give me some suggesting about how to acheive my goal? Thank you so much! I really appreciate it. 

Yiyi

[Astounding]

Once you think about your formulas, you'll realize that 2014-01-01 = 2014 - 1 - 1 = 2012.

To refer to a specific day, use a different form:  '01Jan2014'd

Do not put a space between the closing quote and the letter d

And be careful about using 2004 vs. using 2014

[yiyizhao86]

Thank you so much for you reply! But the date format in the original dataset is YYMMDD10.
Do I need to reformat the date in the original file first?

I changed into the '01Jan2014'd in the if-else statement but still I got weird outputs

Thanks again!

[ballardw]

---

@yiyizhao86 wrote:
Thank you so much for you reply! But the date format in the original dataset is YYMMDD10.
Do I need to reformat the date in the original file first?

I changed into the '01Jan2014'd in the if-else statement but still I got weird outputs

Thanks again!

---

Format has NOTHING to do with arithmetic. Formats are for display or grouping. 

Show the code and the results that are "weird" and the expected results.

[Astounding]

Weird results can be debugged.  Show what you did, and what the result was.  So far, you are moving in right direction and reformatting is not necessary.