SAS-进程频率…内存不足？

Question

I've rarely used proc freq before. I'm trying to run the following and I receive an error says SAS is unable to allocate sufficient memory. The dataset has about 15,000 records. What are my alternatives here?

proc freq data=dsb_un noprint; 
table bsn*dsb / out=dsb_un2(where=(count>1) drop=percent); 
run;

Answer 1

Since you're dropping percent, the following should be identical:

proc freq data=dsb_un noprint;
by bsn;
tables dsb/out=dsb_un2(where=(count>1) drop=percent);
run;

The BY statement should decrease the memory allocation significantly. You also could use PROC SQL in a similar way that would probably fit fine in memory.

The problem is likely that DSB and BSN are mostly unique values each, so you probably have something like 10k+ values for each - making a master table of 10k*10k or 1e8 cells, requiring 8e8 bytes of memory, which may be beyond your available memory for SAS.

Answer 2

I've hit this before as well. The way I got around it was simply not to use proc freq . I believe I used proc summary instead. It can count frequencies just as well.

First a test dataset:

data tmp;
  set sashelp.class;
  dummy = 1;
run;

Using your original freq approach:

proc freq data=tmp noprint; 
  table sex*age / out=freq1(where=(count>1) drop=percent); 
run;

Using a proc summary approach:

proc summary data=tmp noprint nway missing;
  class sex age;
  var dummy;
  output out=freq2(where=(dummy>1) drop=_type_ _freq_) sum=;
run;

Note that proc summary may need a dummy variable that you can calculate against. Hence the creation of the dummy=1 flag in my test dataset.