Comments on: SAS Macros: Letting SAS Do the Typing http://scott.sherrillmix.com/blog/programmer/sas-macros-letting-sas-do-the-typing/ I'm a biologist not a... Sat, 30 Aug 2008 03:09:47 +0000 http://wordpress.org/?v=2.6 By: ScottS-M http://scott.sherrillmix.com/blog/programmer/sas-macros-letting-sas-do-the-typing/#comment-48881 ScottS-M Thu, 22 May 2008 14:36:40 +0000 http://scott.sherrillmix.com/blog/programmer/sas-macros-letting-sas-do-the-typing/#comment-48881 The <code>&&</code> is sort of a funny SAS way of doing arrays or pointers. When SAS runs into a <code>&&</code> it turns it into a single <code>&</code> and remembers it needs to look through the programs for <code>&</code>'s a second time. It's probably easier to show by example. Let's say you have a bunch of names stored in the macro variables <code>&name1</code>, <code>&name2</code>... and you want to get the name from the second one, so you're looking for <code>&name2</code>. To get it, you set <code>%LET i = 2;</code> (in reality you'd probably be looping through or using an if statement but same idea). So you might try <code>&name&i</code> but if you do that SAS will try to fill in both <code>&name</code> and <code>&i</code> at the same time and not give you want you want. However if you do <code>&&name&i</code>, SAS changes <code>&&</code> to <code>&</code> and <code>&i</code> to <code>2</code>, resulting in <code>&name2</code>. Then SAS runs through the code again, sees <code>&name2</code> and fills it in with the desired second name. Let me know, if that wasn't clear it's sort of a complex odd thing. The && is sort of a funny SAS way of doing arrays or pointers. When SAS runs into a && it turns it into a single & and remembers it needs to look through the programs for &’s a second time.

It’s probably easier to show by example. Let’s say you have a bunch of names stored in the macro variables &name1, &name2… and you want to get the name from the second one, so you’re looking for &name2. To get it, you set %LET i = 2; (in reality you’d probably be looping through or using an if statement but same idea). So you might try &name&i but if you do that SAS will try to fill in both &name and &i at the same time and not give you want you want. However if you do &&name&i, SAS changes && to & and &i to 2, resulting in &name2. Then SAS runs through the code again, sees &name2 and fills it in with the desired second name.

Let me know, if that wasn’t clear it’s sort of a complex odd thing.

]]> By: kishore kumar http://scott.sherrillmix.com/blog/programmer/sas-macros-letting-sas-do-the-typing/#comment-48865 kishore kumar Thu, 22 May 2008 12:02:49 +0000 http://scott.sherrillmix.com/blog/programmer/sas-macros-letting-sas-do-the-typing/#comment-48865 what is the '&&' use in sas macros what is the ‘&&’ use in sas macros

]]> By: Getting Help with SAS :: Dammit Jim! http://scott.sherrillmix.com/blog/programmer/sas-macros-letting-sas-do-the-typing/#comment-16631 Getting Help with SAS :: Dammit Jim! Thu, 15 Nov 2007 06:01:52 +0000 http://scott.sherrillmix.com/blog/programmer/sas-macros-letting-sas-do-the-typing/#comment-16631 [...] you can also read my poor attempts at explaining SAS macro variables and SAS macros. Also, if you have any specific questions you can try asking in the comments here and if it’s [...] [...] you can also read my poor attempts at explaining SAS macro variables and SAS macros. Also, if you have any specific questions you can try asking in the comments here and if it’s [...]

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