Problems initializing structure of structure.
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From: Roy on 11 Jun 2010 20:23 The idea is to create a structure that has fields that can also be structures. It's not clear from the manual whether this can be done since in the struct documentation they specifically state that the field values can either be scalars or cells but I have done it in the past so it seems to be allowable. The problem is when I try to do a formal initialization of the struct with structs as fields it doesn't work. The idea was to create the following Values(k).Name (Values has 3 fields Name, a struct called Lot, and a struct called StatSum) Values(k).StatSum (StatSum in turn would have two fields Mean and Std) .StatSum.Mean .StatSum.Std Values(k).Lot(i).Name (Lot would be a struct with 3 fields - Name, StatSum, and Bio) .Lot(i).StatSum .StatSum.Mean .StatSum.Std .Lot(i).Bio (Bio would be struct with 4 fields: Name, StatSum, TechReps, data) .Bio(j).Name .Bio(j).StatSum. .Bio(j).StatSum.Mean .Bio(j).StatSum.Std .Bio(j).TechReps .Bio(j).data I did the following as an initialization but it doesn't seem to work and I can't see why. >> StatSum = struct('Mean',[0],'Std',[0]); bio = struct('Name',{},'StatSum',StatSum,'TechReps',{},'data',[]); Lot = struct('Name',{},'StatSum',StatSum,'Bio',bio); Values = struct('Name',{},'StatSum',StatSum,'Lot',Lot) Values = 0x0 struct array with fields: Name StatSum Lot >> Values.Lot %(nothing for output not even the field names) >> Values.Lot.Bio ??? Dot name reference on non-scalar structure. >> Values.Lot(1).Bio >> Values.Lot(1).Bio(1) >> Lot Lot = 0x0 struct array with fields: Name StatSum Bio >> bio bio = 0x0 struct array with fields: Name StatSum TechReps data >> StatSum StatSum = Mean: 0 Std: 0 >> bio.StatSum >> The smaller structs seem to be there but they aren't being transferred over. Any ideas as to what I'm doing wrong? I thought it might be that I have empty matrices so that is why I initialized StatSum but it still isn't doing anything. RK
From: Walter Roberson on 12 Jun 2010 00:47
Roy wrote: >>> StatSum = struct('Mean',[0],'Std',[0]); > bio = struct('Name',{},'StatSum',StatSum,'TechReps',{},'data',[]); > Lot = struct('Name',{},'StatSum',StatSum,'Bio',bio); > Values = struct('Name',{},'StatSum',StatSum,'Lot',Lot) > > Values = > 0x0 struct array with fields: > Name > StatSum > Lot When you use {} as an initializer for struct(), it indicates that you are initializing a structure of 0 elements. If you want to initialize each element to the empty cell, use {{}} . If you want to initialize each name to the empty string, use '' . >> StatSum = struct('Mean',[0],'Std',[0]); >> StatSum StatSum = Mean: 0 Std: 0 >> bio = struct('Name',{{}},'StatSum',StatSum,'TechReps',{{}},'data',[]); >> bio bio = Name: {} StatSum: [1x1 struct] TechReps: {} data: [] >> Lot = struct('Name',{{}},'StatSum',StatSum,'Bio',bio); >> Lot Lot = Name: {} StatSum: [1x1 struct] Bio: [1x1 struct] >> Values = struct('Name',{{}},'StatSum',StatSum,'Lot',Lot) Values = Name: {} StatSum: [1x1 struct] Lot: [1x1 struct] |