topic Re: Array for character variable with two changing components in SAS Programming

Array for character variable with two changing components

Taasby — Wed, 07 Jul 2021 08:59:41 GMT

Hi everyone

I have a dataset containing data on a weekly basis. Each week has its own (character) variable - e.g. week 32 of 2010 is labelled y1032. What I want to do is to keep only data from 2018, 2019, and 2020 (keeping all weeks within a given year) - i.e keppeing 52*3 = 156 weeks:

- 1801, 1802, ... 1852.

- 1901, 1902, ... 1952

- 2001, 2002, ... 2052

I think an array should do the job. However, I'm having a hard time setting up a proper array as there is a "0" before the first 9 weeks within every year. Any suggestions on how to go over this?

Best,

Frederik

Re: Array for character variable with two changing components

Oligolas — Wed, 07 Jul 2021 09:11:34 GMT

Hi,

what does your data structure look like?

is this what you're looking for?

data have;
   input week $;
   datalines;
1801
1802
1852
1901
1902
1952
2001
2002
2052
1701
1702
1752
2101
2102
2152
;
run;

data want;
   set have;
   if '18'<=:week<=:'20';
run;

Re: Array for character variable with two changing components

Taasby — Wed, 07 Jul 2021 09:17:55 GMT

Each variable is a dummy variable taking on the value of 0 or 1. It is looking like the above, but it would be orded horizontally in the SAS dataset as every week is a variable on its own.

Best,

Frederik

Re: Array for character variable with two changing components

Kurt_Bremser — Wed, 07 Jul 2021 09:31:23 GMT

@Taasby wrote:
.... as every week is a variable on its own.

which is always a VERY BAD IDEA. Do not keep data in structure, see Maxim 19.

As you can see, with a long dataset layout the code practically writes itself.

If you receive data in a wide layout, always transpose to long immediately upon import.

Re: Array for character variable with two changing components

FreelanceReinh — Wed, 07 Jul 2021 10:36:42 GMT

Hi @Taasby,

@Taasby wrote:

Each week has its own (character) variable - e.g. week 32 of 2010 is labelled y1032. What I want to do is to keep only data from 2018, 2019, and 2020 (keeping all weeks within a given year) - i.e keppeing 52*3 = 156 weeks

Try this:

data want;
set have(keep=y18: y19: y20:);
run;

Or this:

data want;
set have(keep=y1801-y1852 y1901-y1952 y2001-y2052);
run;

In the second case, make sure that you don't miss a week 53. Add more variables to the KEEP= lists if needed.

Re: Array for character variable with two changing components

Taasby — Wed, 07 Jul 2021 11:27:00 GMT

It did the job! Cheers! 🙂