CODEWITHSUNDEEP
sasappend
zuluk
zuluk

Reputation: 1577

Unexpected behaviour by proc append

I execute the following code:

data temp1;
  set sashelp.class;
  table=1;
run;

data temp2;
  set sashelp.class;
  table=2;
run;

proc append base=temp1(drop=sex) data=temp2 force;
run;

I thought that sex will be dropped from temp1. So sex is missing it will be also dropped from temp2 and result set does not contain column sex.

However I am irritated by the real result: enter image description here

Why is sex for table=1 filled and for table=2 empty?

Upvotes: 1

Views: 360

Answers (1)

Allan Bowe
Allan Bowe

Reputation: 12691

As @data null mentions, when using proc append the base dataset is not altered. This is the primary reason to use proc append - it does not require a 'pass' of the base dataset, and just appends the data to the end.

In this (rather special) case, the sex variable is considered dropped and so it is not written/ visible for the subsequent append.

Also (thanks again @data null) there was a clue here from the WARNING in the log. As a matter of best practice, one should always aim to write code that runs without ERRORs or WARNINGs..

Upvotes: 3

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