CODEWITHSUNDEEP
arraysmatlabvectorizationvariable-assignmentmatlab-struct
Andrew
Andrew

Reputation: 25

Vectorizing structure field access (or modify) matlab? Is it even possible?

After years of anonymity I've just created my account to ask a question which has been bugging me for a while and I just can't seem to find an answer. I really, really tried! Here it goes:

If you have the matlab structure array:

something(1).toSay = 'qwe';

something(2).toSay = 'asd';

something(3).toSay = 'zxc';

Is there any way to vectorize the reassignment of these 3 entries of the field toSay?

Like 

something = magicFunction(something, [1:3], 'toSay', {'newString1','newString2','newString3'})

final results being: 

something(2).toSay >> 'newString2'

I've tried something along with the setfield function, but couldn't make it work. All I'm trying to do with this question is avoid a for-loop.

Question 2: Would it make a difference if it was a cell array of structures and not a structure array?

Upvotes: 2

Views: 51

Answers (1)

Suever
Suever

Reputation: 65430

You can place your replacement strings within a cell array and then use {:} indexing to create a comma separated list on the right-hand side of the assignment. On the left-hand side, something(1:3).toSay already creates a comma separated list so we can enclose it in [] to assign the values on the right to their corresponding fields on the left.

newvalues = {'newString1', 'newString2', 'newString3'};
[something(1:3).toSay] = newvalues{:};

See: Assigning output from a comma separated list and Assigning to a comma separated list

With respect to your second question, making it a cell array of structs will require an additional step as you can't create a comma separated list directly when the structs are within a cell array. You'd have to first convert them to a struct array

sarray = [something{1:3}];
[sarray.toSay] = newValues{:};
something(1:3) = num2cell(sarray);

Upvotes: 1

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