How to filter in reference to date of another variable

[bretthouston]

I am hoping to filter my dataset by date in reference to the date of another variable. In the example below, I would like to keep the observation if date2 is within date1 + 7 days (or if missing). [Alternatively, I'd like to remove an observation if date2 is present and not within date1 + 7 days]. 

Sample dataset:

Obs            Date1           Date2

1               10/21/88        10/23/88      

2                6/18/89         6/30/89

3                2/20/89          2/22/89

4                4/18/87           .

In the set above, I would like to keep obs 1, 3 & 4.

Thank-you in advance!

[andreas_lds · Accepted solution]

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@bretthouston wrote:

I am hoping to filter my dataset by date in reference to the date of another variable. In the example below, I would like to keep the observation if date2 is within date1 + 7 days (or if missing). [Alternatively, I'd like to remove an observation if date2 is present and not within date1 + 7 days]. 

Sample dataset:

Obs            Date1           Date2

1               10/21/88        10/23/88      

2                6/18/89         6/30/89

3                2/20/89          2/22/89

4                4/18/87           .

In the set above, I would like to keep obs 1, 3 & 4.

Thank-you in advance!

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Assuming the dates are dates and not strings, you can use subsetting-if in a datastep:

if missing(date2) or (date1 <= date2 <= date1+7);