I am very confused with working with and manipulating dates from a data file in SAS. I have a text file that I use as a input file in a data step where dates are listed as 20150819, for example. When I input these, I usually input as a "date_var $8." informat, storing the variable as an 8-digit number, exactly as it appears on my text file input. Sometimes, I will input them as "date_var 8." informat, storing the variable as an 8-digit number. Neither of these informats seem to be helpful, because I get errors trying to use the YRDIF function. The only way I can get the YRDIF function to work is if I input the variables using the yymmdd8. informat. When I finish all my data manipulation, I want the output displayed as an 8-character date (ie 20150819). Ultimately, I don't want to informat the same variable three different ways just so that I can use the yymmdd8. informat for date calculations. Can someone please explain the differences between informats and formats for dates and why the manipulation and conversions are necessary?
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