Problem 2170. Dealfun (1.0)

Created by Jan Orwat

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Short description.Write a function dealfun:<pre class="language-matlab">[y1,y2,...,yn]=dealfun(fhandle,x1,x2,...,xn)
</pre>which evaluates the function handle fhandle on arguments x1,x2,...,xn independently and deal solutions to outputs y1,y2,...,yn (so nargin==nargout+1)Long description.Several repetitions of exacly same operation on different variables can be a pain in the neck when you are editing your code.<pre class="language-matlab">a=a^2+mod(a,3); a=a^3+4*a+mod(a,3);
b=b^2+mod(a,3); --&gt; b=b^3+4*a+mod(a,3);
c=c^2+mod(a,3); c=c^3+4*a+mod(a,3);
d=d^2+mod(a,3); d=d^3+4*a+mod(a,3);
</pre>Of course there are as many strategies as programmers. There are also many helpful functions like cellfun arrayfun deal feval. But sometimes usage of those functions in one line looks unclear and it doesn't make editing faster. Usage of dealfun could look like that:<pre class="language-matlab">funh=@(A)A^2+mod(A,3); --&gt; funh=@(A)A^3+4*A+mod(A,3);
[a,b,c,d]=dealfun(@funh,a,b,c,d);
</pre>example:<pre class="language-matlab">&gt;&gt; [a,b,c,d]=dealfun(@sum,ones(1),ones(2),ones(3),ones(4))
a = 1
b = 2 2
c = 3 3 3
d = 4 4 4 4
</pre>easy change:<pre class="language-matlab">&gt;&gt; [a,b,c,d]=dealfun(@numel,ones(1),ones(2),ones(3),ones(4))
a = 1
b = 4
c = 9
d = 16
</pre>

*Short description.*

Write a function _dealfun_:
  
  [y1,y2,...,yn]=dealfun(fhandle,x1,x2,...,xn)

which evaluates the function handle _fhandle_ on arguments _x1,x2,...,xn_  independently and deal solutions to outputs _y1,y2,...,yn_ (so nargin==nargout+1)

*Long description.*

Several repetitions of exacly same operation on different variables can be a pain in the neck when you are editing your code.

a=a^2+mod(a,3);       a=a^3+4*a+mod(a,3);
  b=b^2+mod(a,3);  -->  b=b^3+4*a+mod(a,3);
  c=c^2+mod(a,3);       c=c^3+4*a+mod(a,3);
  d=d^2+mod(a,3);       d=d^3+4*a+mod(a,3);

Of course there are as many strategies as programmers. There are also many helpful functions like _cellfun arrayfun deal feval_. But sometimes usage of those functions in one line looks unclear and it doesn't make editing faster. Usage of _dealfun_ could look like that:

funh=@(A)A^2+mod(A,3);   -->   funh=@(A)A^3+4*A+mod(A,3);
  [a,b,c,d]=dealfun(@funh,a,b,c,d);

example:

>> [a,b,c,d]=dealfun(@sum,ones(1),ones(2),ones(3),ones(4))
a =  1
b =  2     2
c =  3     3     3
d =  4     4     4     4

easy change:

>> [a,b,c,d]=dealfun(@numel,ones(1),ones(2),ones(3),ones(4))
a =  1
b =  4
c =  9
d =  16

Solve

Solution Stats

39 Solutions
20 Solvers

Last Solution submitted on Oct 20, 2021

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2 Comments

2 Comments

J.R.! Menzinger on 10 Feb 2014

I think you try to get the "i" and "j" that the function nonzeros does not give:
http://www.mathworks.de/de/help/matlab/ref/nonzeros.html

Jan Orwat on 10 Feb 2014

Thanks José, I've fixed bugs.

Solution Comments

Solution 400520

2 Comments

2 Comments

J.R.! Menzinger on 11 Feb 2014

"0" and not "false"... nice shot!

埃博拉酱 on 4 Aug 2021

So false is considered a function call but not a constant? What an absurd cody trick …

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