Matlab dynamic fieldnames structure with cell arrays

问题

How can i access the following structure path with dynamic fieldnames:

var = 'refxtree.CaseDefinition.FlowSheetObjects.MaterialStreamObjects{8}.MaterialStreamObjectParams.Pressure.Value.Text';

fields = textscan(var,'%s','Delimiter','.');

refxtree.(fields{:}) does not work because MaterialStreamObjects contains a cell array of which I want to access the 8th cell and then continue down the structure path.

In the end I want to get and set the fieldvalues.

回答1:

You need to build the appropriate input to subsref, possibly using substruct. Look at the MATLAB help.

回答2:

You can define an anonymous function to navigate this particular kind of structure of the form top.field1.field2.field3{item}.field4.field5.field6.field7 (as an aside: is it really necessary to have such a complicated structure?).

getField = @(top,fields,item)top.(fields{1}).(fields{2}).(fields{3}){item}.(fields{4}).(fields{5}).(fields{6}).(fields{7})

setField = @(top,fields,item,val)subsasgn(top.(fields{1}).(fields{2}).(fields{3}){item}.(fields{4}).(fields{5}).(fields{6}),struct('type','.','subs',fields{7}),val);

You use the functions by calling

fieldValue = getField(refxtree,fields,8);
setField(refxtree,fields,8,newFieldValue);

Note that fields is required to have seven elements. If you want to generalize the above, you will have to dynamically create the above functions

回答3:

In this case, it is easier to just use EVAL:

str = 'refxtree.CaseDefinition.FlowSheetObjects.MaterialStreamObjects{8}.MaterialStreamObjectParams.Pressure.Value.Text';

%# get
x = eval(str)

%# set
evalc([str ' = 99']);

来源：https://stackoverflow.com/questions/7596575/matlab-dynamic-fieldnames-structure-with-cell-arrays