topic Re: counting in SAS Programming

counting

davidnamh — Tue, 24 Jun 2014 15:39:04 GMT

Hi, I would like to count for 0 by Name only if it comes out before 1 so any 0 comes out after 1 should be ignored.

Could anyone help me how to do that ? Thanks

data have;

input Name $ A;

datalines;

John 0

John 1

John 0

David 0

David 1

David 0

Smith 1

Jason 0

Jason 1

Jason 0

Jason 1

Jason 0

;

run;

data want;

input Name $ Cnt;

datalines;

John 8

David 3

Smith 0

Jason 1

;

run;

Re: counting

Haikuo — Tue, 24 Jun 2014 15:45:44 GMT

data have;

input Name $ A;

datalines;

John 0

John 1

John 0

David 0

David 1

David 0

Smith 1

Jason 0

Jason 1

Jason 0

Jason 1

Jason 0

;

run;

data want;

set have;

by name notsorted;

if first.name then

do;

cnt=0;

_f=0;

end;

cnt+a=0;

_f+a=1;

if _f=1 and a=1 then

output;

drop _f a;

run;

Re: counting

davidnamh — Tue, 24 Jun 2014 17:08:33 GMT

Thank you so much Hai Kuo

Re: counting

jwillis — Tue, 24 Jun 2014 19:42:41 GMT

Hai Kuo,

Please educate me on how your elegant code works. I have never seen your style before. How do the first two lines below work?

cnt+a=0;

_f+a=1;

if _f=1 and a=1 then

output;

Obs Name A action cnt _f

1    John     0    delete      1     0
2    John     0    delete      2     0
3    John     0    delete      3     0
4    John     0    delete      4     0
5    John     0    delete      5     0
6    John     0    delete      6     0
7    John     0    delete      7     0
8    John     0    delete      8     0
9    John     1    output      8     1
10    John     1    delete      8     2
11    John     1    delete      8     3
12    John     1    delete      8     4
13    John     1    delete      8     5
14    John     1    delete      8     6
15    John     0    delete      9     6
16    John     0    delete     10     6
17    John     0    delete     11     6
18    John     0    delete     12     6
19    David    0    delete      1     0
20    David    0    delete      2     0
21    David    0    delete      3     0
22    David    1    output      3     1
23    David    0    delete      4     1
24    David    0    delete      5     1
25    David    0    delete      6     1
26    David    0    delete      7     1
27    Smith    1    output      0     1
28    Smith    1    delete      0     2
29    Smith    1    delete      0     3
30    Jason    0    delete      1     0
31    Jason    1    output      1     1
32    Jason    0    delete      2     1
33    Jason    0    delete      3     1
34    Jason    1    delete      3     2
35    Jason    0    delete      4     2

Re: counting

Haikuo — Tue, 24 Jun 2014 20:23:56 GMT

Apologize for my own laziness, but maybe it is good for job security?

cnt+a=0;

_f+a=1;

are equivalent to:

cnt+(a=0);

_f+(a=1);

So as you can see now, it is just a boolean expression. When a=0 is true, then (a=0)=1, else 0. So as (a=1). cnt+(a=0) is to count the how many (a=0)s, while _f+(a=1) is to count the number of (a=1)s. And when it hits the first (a=1) (defined by _f=1 and a=1), then output.

Regards,

Haikuo

Re: counting

jwillis — Wed, 25 Jun 2014 11:24:04 GMT

Brilliant. Thank you. I did the same thing COBOL style long hand. You accomplished in 3 lines what I used 10+ lines to do.

Re: counting

Haikuo — Wed, 25 Jun 2014 12:22:08 GMT

Didn't know you are an old-timer mainframe guy.

Re: counting

jwillis — Wed, 25 Jun 2014 12:36:27 GMT

That I am. And I am trying to learn the new languages. In the olden days of dinosaurs, you could follow code step by step and intuit the logic and goals behind the code. In the new-fangled days of cars driving themselves, code is written in shorthand, Succint, compressed and computers can interpret the "shorthand" based on position of characters, or absence of characters, in a string of values.