How to store functions in a array

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Bradley Kitzul
Bradley Kitzul 2020-12-9
评论： Bradley Kitzul 2020-12-10
Below is a simple example of the code I am trying to implement (using it as proof of concept). I am trying to make an array (d) with 5 functions/equations and incrementing with i and at each slot of i. When I run the code the "i" in the x/i term is not incrementing with the for loop. I am trying to have the output of this code an array and each term in the array = [x/1, x/2, x/3, x/4, x/5].
for i=1:5
d{i} = @(x) x/i
end

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回答（2 个）

Steven Lord
Steven Lord 2020-12-9
Ran in:
The anonymous functions do "remember" the value the variable i had when they were created, even if they don't show it. If you want to see this use the functions function (but I strongly recommend against using functions as part of your production code. Just use it for debugging.)
for k = 1:5 % I tend not to use i as a variable, as it already means sqrt(-1) in MATLAB
d{k} = @(x) x./k;
end
d{4}
ans = function_handle with value:
@(x)x./k
y = d{4}([8 12]) % results in [2 3]
y = 1×2
2 3
●
f = functions(d{4});
f.workspace{1}
ans = struct with fields:
k: 4
Walter Roberson
Walter Roberson 2020-12-9
Ran in:
for i=1:5
d{i} = @(x) x/i;
end
d
d = 1x5 cell array
{@(x)x/i} {@(x)x/i} {@(x)x/i} {@(x)x/i} {@(x)x/i}
d{3}(7)
ans = 2.3333
It might not display the way you hoped, but it does work.
If it is important to it displays the way you want, you are going to have to construct it from strings.
for i=1:5
d{i} = str2func("@(x) x/" + i);
end
d
d = 1x5 cell array
{@(x)x/1} {@(x)x/2} {@(x)x/3} {@(x)x/4} {@(x)x/5}
d{3}(7)
ans = 2.3333

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