MATLAB: Remove specific array in struct

MATLABrmfieldstruct

Hey guys,

I'm stuck with one simple issue. I am practicing on 'struct' now. As practice, I created a stuct 'account' with fields 'owner', 'balance', and 'number' which is 1×3 array.

Then I was trying to creat the second account 'account(2)', however I accidentally typed 'account(2).name' which made a 1×4 array.

Tried rmfield, but failed:"Subscripted assignment between dissimilar structures."

Can someone help? Thanks

account(2) = rmfield(account(2),field)

Best Answer

account = struct('owner','Harry','balance',0,'number',42)

account =

struct with fields:

owner: 'Harry'

balance: 0

number: 42

>> account(2) = struct('name','Harry','balance',0,'number',42)

Subscripted assignment between dissimilar structures.

>>Not sure how you created it

>> account(2).name = 'Harry'

account =

1×2 struct array with fields:

owner

balance

number

name

>> account

account =

1×2 struct array with fields:

owner

balance

number

name

>> account = rmfield(account,'name')

account =

1×2 struct array with fields:

owner

balance

number

or maybe

account(2).owner = account(2).name; # first

Related Solutions

MATLAB: Adding empty numerical fields in structure array

Yes, that's simple:

    A.field4 = [];
    A.field5 = [];

&nbsp

In response to comment

    >> clear A
    >> A.f1=1;
    >> A.f2=2;
    >> A.field5 = [];
    >> A.field4 = [];
    >> A
    A = 
            f1: 1
            f2: 2
        field5: []
        field4: []
    >>

So far so good.

    >> A=[A,A]
    A = 
    1x2 struct array with fields:
        f1
        f2
        field5
        field4
        f3
    >> A.f4 = []
    Incorrect number of right hand side elements in dot name assignment.  
    Missing [] around left hand side is a likely cause.

Ok, I missed that you have a struct array

    >> A(1).f4 = []
    A = 
    1x2 struct array with fields:
        f1
        f2
        field5
        field4
        f3
        f4
    >> A(1).f4 
    ans =
         []
    >> A(2).f4
    ans =
         []

Or better

    >> [A.f5] = deal([])
    A = 
    1x2 struct array with fields:
        f1
        f2
        field5
        field4
        f3
        f4
        f5

MATLAB: How to save struct data in for loop

You can overcome the problem by pre-allocating the array of structures as follows:

clear all; % Clear the workspace
N = 10;
% Pre-allocate the array of structures
structArray1(N) = struct('field1',[], 'field2',[], 'field3',[]);
  
for i=1:N
    field1 = "field1";
    field2 = "field2";
    field3 = "field3";
    
    structArray1(i)=getStruct(field1, field2,field3);  
end

Alternatively, instead of pre-allocating before the loop, you can also loop backwards so that all the memory allocation is done in the first iteration itself.

N = 10;
for i=N:-1:1
    field1 = "field1";
    field2 = "field2";
    field3 = "field3";
    
    structArray2(i)=getStruct(field1, field2,field3);  
end
structArray2 = fliplr(structArray2);  % Get back the array of structures in correct order

The getStruct function is as follows:

function outStruct = getStruct(field1, field2,field3)
% returns a struct with 3 fields
     outStruct.field1 = field1;
     outStruct.field2 = field2; 
     outStruct.field3 = field3; 
end

Best Answer

Related Solutions

MATLAB: Adding empty numerical fields in structure array

MATLAB: How to save struct data in for loop

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