Since when has it been possible to dot-index the output of a class method?

3 次查看（过去 30 天）
Catalytic
Catalytic 2022-5-18
评论： Bruno Luong 2022-7-21
Ran in:
Since when has it been possible to directly dot-index the output of a class method call, like this -
classdef myClass
properties
p
end
methods
function obj=myClass(val)
obj.p=val;
end
function obj=increment(obj)
obj.p=obj.p+1;
end
end
end
obj=myClass(2)
obj =
myClass with properties: p: 2
obj.increment.p
ans = 3
And why then, it is still not possible to do something similar with function calls -
subfunc.a
Error: File: test.m Line: 1 Column: 1
Using the dot operator to index into the output of function 'subfunc' is not
supported.
function S=subfunc()
S.a=1;
S.b=2;
end
  1 个评论
Matt J
Matt J 2022-5-18
Ran in:
Quite intriguing. It works with brace indexing, too:
classdef myClass
properties
p
end
methods
function obj=myClass(val)
obj.p=val;
end
function out=num2cell(obj)
out=num2cell(obj.p);
end
end
end
obj=myClass([30,10,70]);
obj.num2cell{1}
ans = 30
obj.num2cell{3}
ans = 70

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Walter Roberson
Walter Roberson 2022-5-19
Since R2019b.
https://www.mathworks.com/help/matlab/release-notes.html?category=language-programming&rntext=&startrelease=R2019b&endrelease=R2019b&groupby=release&sortby=descending&searchHighlight=
Indexing: Use dot indexing into function calls
You can now use dot indexing to index into the result of a function call. MATLAB evaluates the function and then applies the dot indexing operation to the result.
For example, this function creates a structure:
function out = createStruct(in)
out = struct("aField", in);
end
You can call this function and immediately access the structure field it creates:
createStruct(3).aField
For more information, see Indexing into Function Call Results.
  7 个评论
显示 5更早的评论
Walter Roberson
Walter Roberson 2022-7-21
Oh, of course, that second example thinks it is indexing into a variable named 'struct', makes more sense now.
Bruno Luong
Bruno Luong 2022-7-21
Ran in:
It does not do what you want but it runs without error
figure(gcf().Number).Name = 'hello'
figure = struct with fields:
Name: 'hello'

请先登录，再进行评论。

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Loops and Conditional Statements 的更多信息

标签

产品


版本

R2021b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by