how define a conditional handle function?

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xosro 2017-5-4

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评论： Jan 2017-5-8

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As you know, for

f=@(x) sin(x)/x;

we get f(0)=NaN

if we would like get f(0)=0

again with

f=@(x) (x==0)*0+(x~=0)*sin(x)/x;

we will receive f(0)=NaN.

how can i dominate this problem?

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Adam 2017-5-4

编辑：Adam 2017-5-4

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Please try to ensure you format your question in a readable way. The

if true
end

lines should not keep appearing around every bit of code. I don't really know why the '{} Code' button is setup to do this as so many people end up with it included in their code. Also don't include the lines of your question in the middle of one large code block - it is very confusing to read and separate out what is actually code and what is part of the question information.

I did the editing for you this time.

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回答（2 个）

Torsten 2017-5-4

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编辑：Torsten 2017-5-4

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function main
x = [3 7.5 0 -0.03];
y = f(x)  
function y = f(x)
  i = find(x==0);                                                               
  x(i) = 1;                          
  y = sin(x)./x;                                                      
  y(i) = 0; 
end

Best wishes

Torsten.

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Jan 2017-5-4

编辑：Jan 2017-5-4

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Or a little bit simpler:

function y = f(x)
y       = sin(x) ./ x;
y(x==0) = 0;
end

@xosro: Do not confuse a "handle function" with an "anonymous function", which is accessed by a "function handle".

Torsten 2017-5-4

编辑：Torsten 2017-5-4

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My guess is that this function cannot be defined as a "one-liner" as

f=@(x)....

Best wishes

Torsten.

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Jan 2017-5-4

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编辑：Jan 2017-5-4

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A function (see Torsten's answer) will be nicer and more efficient than an anonymous function. But if you realy have any good reasons:

f = @(x) sin(x) / [Inf(x==0), x(x~=0)];

This works for scalar x only. This would be better, because it is immediately clear, what it does:

function y = f(x)
y       = sin(x) ./ x;
y(x==0) = 0;
end

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xosro 2017-5-5

@Jan Simon: Ok, "nested function" is a good idea, but for using variables as inputs, i had some limitation so i have used "global variables" for using variables between scripts.

Thank you and other dears