{"id":311,"date":"2010-01-11T07:00:01","date_gmt":"2010-01-11T12:00:01","guid":{"rendered":"https:\/\/blogs.mathworks.com\/steve\/2010\/01\/11\/about-the-unused-argument-syntax-in-r2009b\/"},"modified":"2019-10-29T13:20:01","modified_gmt":"2019-10-29T17:20:01","slug":"about-the-unused-argument-syntax-in-r2009b","status":"publish","type":"post","link":"https:\/\/blogs.mathworks.com\/steve\/2010\/01\/11\/about-the-unused-argument-syntax-in-r2009b\/","title":{"rendered":"About the unused-argument syntax in R2009b"},"content":{"rendered":"
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Last fall Loren<\/a> wrote a blog post<\/a> about a new syntax in R2009b for ignoring function inputs or function outputs. For example, suppose you call sort<\/tt> and only want the second output. In R2009b you can do that using this syntax:\r\n <\/p>

 [~, idx] = sort(A);<\/pre>
The tilde character here is used as a placeholder to indicate that you don't need the first output argument of sort<\/tt>.\r\n   <\/p>\r\n   
For another example, suppose you write a function that has to take three input arguments (because another function is always\r\n      going to pass it three arguments), but your function doesn't need the second argument.  Then you can write the first line\r\n      of your function this way:\r\n   <\/p>
 function out = myfun(A, ~, C)<\/pre>
This new syntax has drawn a startling amount of discussion, both in the comments<\/a> on Loren's post as well as in the comp.soft-sys.matlab newsgroup. (See the thread \"Getting indexes of rows of matrix with more than n repetitions,\"<\/a> for example.)\r\n   <\/p>\r\n   
Responses to this new syntax have fallen into roughly four categories:<\/p>\r\n   
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