PROC COMPARE: Processing output dataset

[DavidJ]

In the following example:
DATA A;
KEY = 100;
Value1 = 200; Value2 = 400;
run;

Data B;
KEY = 100;
Value1 = 200; Value2 = 410;
run;

proc compare BASE=A COMPARE=B CRITERION=2 NOSUMMARY METHOD=ABSOLUTE NOPRINT OUTNOEQUAL OUT=MYDIFFS;
ID KEY;
run;

The dataset MYDIFFS contains 1 record, as follows (and as expected):
_TYPE_ = DIF
_OBS_ = 1
KEY = 100
Value1 = E
Value2 = 10

However if I try and process the MYDIFFS dataset and attempt to change the E to a 0, SAS will throw an error since Value1/2 are numeric. Is there a simple solution to this?

[data_null__]

The value is actually special missing value E. To refere to this in code use .E

if value1 eq .E then ...

[DavidJ]

15 years of coding SAS and I had never heard of that one. Thanks.

[data_null__]

You might like the "generic" missing function. You don't need to know the type.

if missing(value1) then...

Also coalesce if nice for a missing to non-missing value conversion.

[pre]
44 data _null_;
45 do y = 1,.e,3;
46 z = coalesce(y,0);
47 put (_all_)(=);
48 end;
49 run;

y=1 z=1
y=E z=0
y=3 z=3
[pre]

[Doc_Duke]

"Special missing values" have been around since at least version 5.

They are extensively used in certain pockets of analysis (like surveys where you want to code the reason that a value is missing), but many people go through their entire SAS careers without needing them.

I've rarely needed them, but when I did they were a very valuable tool.

Doc