topic Re: Bug converting characters to numbers in SAS Programming

Bug converting characters to numbers

JS — Thu, 27 Oct 2016 01:16:14 GMT

I'm trying to convert a set of character strings into numbers, and it's not as expected.

Anyone have any ideas on how to trouble shoot?

data want;
set have;
num=input(char,best32.);
run;

Obs num char

1	323242600026000064512	323242600026000122499
2	313244000040000684032	313244000040000698990
3	313242000020000145408	313242000020000198990
4	314245000050000134144	314245000050000159970
5	323242600026000261120	323242600026000222499
6	323242600026000261120	323242600026000222499
7	313244000040000290816	313244000040000298990
8	323242600026000064512	323242600026000122499
9	423242250022500433920	423242250022500512797
10	323245000050000134144	323245000050000171980

Re: Bug converting characters to numbers

ChrisNZ — Thu, 27 Oct 2016 01:55:26 GMT

Assuming you are on a PC, the maximum precision that can be stored by SAS integers is 16 digits (2**53) since SAS stores numbers in 64 bits (8 bytes), and some of these are not used for the mantissa (the digits of the number). Your numbers are longer than this.

If you store real numbers, full precison is not always possible, and SAS has further issues (see https://communities.sas.com/t5/Base-SAS-Programming/Expected-numeric-precision-behaviour-or-unexpected-issue/td-p/287071).

Re: Bug converting characters to numbers

SASKiwi — Thu, 27 Oct 2016 03:00:04 GMT

What do these numbers represent? Leave them as character if you are not doing mathematics on them.

Re: Bug converting characters to numbers

JS — Thu, 27 Oct 2016 18:56:54 GMT

Thanks Chris! This was exceptionally informative and helpful.

Re: Bug converting characters to numbers

JS — Thu, 27 Oct 2016 18:57:43 GMT

Thanks SASKiwi. This was a unique problem that we ran into, and in the future we're going to restructure our coding algorithms to use character strings instead.