如何解决表中值类的表示
classdef MyVal
properties
foo
end
methods
function self = MyVal(varargin)
if nargin > 0
self.foo = varargin{1};
end
end
end
end
并在表格中使用它:
foo(1) = MyVal(1); foo(2) = MyVal(2);
t = table(foo')
输出为:
t =
2×1 table
Var1
___________
[1×1 MyVal]
[1×1 MyVal]
是否有任何方法必须在 MyVal
(或表的任何属性)中定义,以允许更改表中值的表示?我不想转换传递给 table
的数据,因为我想在表中建立索引时检索 MyVal
的实例。
解决方法
您可以为 table
创建自定义包装器。这有点棘手,因为 MATLAB 不允许您从 table
类继承,但是通过重载 subsref
和 subsasgn
运算符,您无论如何都可以获得大部分功能......>
我在这个答案的底部包含了这个类,因为它有点长,用法如下:
>> foo(1) = MyVal(1); foo(2) = MyVal(2);
>> t = MyTable(foo') % Omitting the ";" calls our overloaded "disp" function
t =
Var1
____
1
2
您也可以使用 foo
来提取数字数据(即 t.numeric
属性以及其他数据),尽管我怀疑您需要在此使用 table2array
与 uitable
一起使用,就像使用普通的 table
一样。
classdef MyTable
properties ( Access = private )
table_
end
properties ( Dependent = true )
numeric
end
methods % Constructor and getter
function obj = MyTable( varargin )
% Store as a normal table internally
obj.table_ = table( varargin{:} );
end
function num = get.numeric( obj )
% By calling obj.numeric,output the table but with MyVal
% objects replaced by their "foo" property.
% This could be passed into a uitable,and is used in disp()
cls = varfun( @(x)isa(x,'MyVal'),obj.table_,'OutputFormat','uniform' );
num = obj.table_;
for ii = find(cls)
num.(num.Properties.VariableNames{ii}) = [num.(num.Properties.VariableNames{ii}).foo].';
end
end
end
methods % Overloaded to emulate table behaviour
function disp( obj )
% Overload the disp function (also called when semi colon is
% omitted) to output the numeric version of the table
disp( obj.numeric );
end
% Overload subsref and subsasgn for table indexing
function varargout = subsref( obj,s )
[varargout{1:nargout}] = builtin( 'subsref',s );
end
function obj = subsasgn( obj,s,varargin )
obj.table_ = builtin( 'subsasgn',varargin{:} );
end
% Have to overload size and isa for workspace preview
function sz = size( obj,varargin )
sz = size( obj.table_,varargin{:} );
end
function b = isa( obj,varargin )
% This is only OK to do because we overloaded subsref/subsasgn
b = isa( obj.table_,varargin{:} );
end
end
end
,
只有一半答案
我找不到自定义对象 table
的显示的方法,但是如果您可以通过使用对象的 arrays
获得,则有一种方法,在 {{3} 中描述}.
对于您的示例,您必须使用以下命令派生类:matlab.mixin.CustomDisplay
,然后覆盖 displayNonScalarObject
方法:
classdef MyVal < matlab.mixin.CustomDisplay
properties
foo
end
methods
function self = MyVal(varargin)
if nargin > 0
self.foo = varargin{1};
end
end
end
methods (Access = protected)
function displayNonScalarObject(objAry)
dimStr = matlab.mixin.CustomDisplay.convertDimensionsToString(objAry);
cName = matlab.mixin.CustomDisplay.getClassNameForHeader(objAry);
headerStr = [dimStr,' ',cName,' members:'];
header = sprintf('%s\n',headerStr);
disp(header)
for ix = 1:length(objAry)
o = objAry(ix);
% OPTION 1:
% For a class with a sinle property,no need to call the
% big guns,just build your own display:
disp( [num2str(ix) ': foo = ' num2str(o.foo) ] ) ;
% OR OPTION 2: (comment option1 if you use this)
% If your class had multiple properties and you want to
% display several of them,use the MATLAB built-in functions:
% create a structure with the property names you need
% displayed:
% propList = struct('foo',o.foo,'prop2',o.prop2,'prop3',o.prop3);
% Then let MATLAB handle the display
% propgrp = matlab.mixin.util.PropertyGroup(propList);
% matlab.mixin.CustomDisplay.displayPropertyGroups(o,propgrp);
end
end
end
end
现在,如果您构建类的数组,则显示如下:
>> foo(1) = MyVal(1); foo(2) = MyVal(2);
>> foo
foo =
1x2 MyVal members:
1: foo = 1
2: foo = 2
当然,这只是一个示例,并且是高度可定制的。不幸的是,我找不到让 table
对象起作用的方法。
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