How to scan through several structures in MATLAB?

问题

I have some structure arrays (like structure1, structure2, structure3,...) with similar field names. I want to scan through all the structures and return only those whose first field is 5 (Field1==5). I have this code so far,

for k=1:3
    s=sprintf('Structure%d',k)
    Structure=load(s)
    idx=cellfun(@(x) x==5, {Structure.Field1})
    out=Structure(idx)
    v{k}={Structure.Field1}
end

but it gives me this error:

Reference to non-existent field 'Field1'.

Can someone please point out whats wrong here?

Thanx

回答1:

for k=1:3
    s=sprintf('Structure%d',k)
    Structure=load(s)
    eval(['newStructure(k)=Structure.' s]);
    idx(k)=cellfun(@(x) x==5, {newStructure(k).Field1})
end
%extract the structures from newStructure which have 1 in idx
out=newStructure(idx); %idx should be a logical array
for i=1:size(out,2)
    v(i)=out(i).Field1;
end

This should work perfectly.

回答2:

It appears as if some of your saved structures do not have 'Field1' as a field in them.
In that case, you might want to try something else.
First define a function (in m-file)

function res = iff( cond, true_case, false_case )
%
% conditional execution of two function handles
% 
% true_case and false_case are function handles expecting no inputs
%
if cond
   res = true_case();
else
   res = false_case();
end

Once you have this function you can use it in the cellfun

idx = cellfun( @(x) iff( isfield(x, 'Field1'), @() x.Field1 == 5, @() false), Structure );

来源：https://stackoverflow.com/questions/15050003/how-to-scan-through-several-structures-in-matlab

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matlab

structure