Update multiple values in a struct array

I have a struct array S with multiple fields. One of the fields contains numeric values. I want to add a scalar quantity to every entry in this field and overwrite the existing value. I can do this with a loop as follows:

for a = 1:length(S)
    S(a).value = S(a).value + 5;
end

Is there a one-line function that does the equivalent?

Answer 1

[Matt J]

No, but easy enough to make one:

[s(1:2).f]=deal(1,2);
s.f

ans = 1

ans = 2

s=incremStruct(s,'f',5);
s.f

ans = 6

ans = 7

function S=incremStruct(S,field,increm)
  for i = 1:length(S)
    S(i).(field) = S(i).(field) + increm;
 end
end

Answer 2

[Matt J]

You can do it in 2 lines,

C=num2cell([S.value]+5);
[S.value]=deal(C{:})

Answer 3

[Voss]

This works whether the field is a scalar in each element of S or not:

S = struct('value',{[1 2 3] [2 3; 4 5] [] 6}); % initial struct array
celldisp({S.value});

 
ans{1} =
 
     1     2     3

 
 
ans{2} =
 
     2     3
     4     5

 
 
ans{3} =
 
     []
 
 
ans{4} =
 
     6

 

C = cellfun(@(x)x+5,{S.value},'UniformOutput',false); % perform the additions
[S.value] = C{:}; % assign the result back to the struct array

celldisp({S.value});

 
ans{1} =
 
     6     7     8

 
 
ans{2} =
 
     7     8
     9    10

 
 
ans{3} =
 
     []
 
 
ans{4} =
 
    11