MATLAB: How to use cellfun with a struct?

Question

Imagine a cell array that consists of identical structs (in terms of layout), as the example cellArray below. How can I apply cellfun to a specific field of these structs?

cellArray{1,1}.val1 = 10;
cellArray{1,1}.val2 = 20;
cellArray{1,2}.val1 = 1000;
cellArray{1,2}.val2 = 2000;

How to use cellfun in order to add the value 50 to all cells, but only to the field val2?

out = cellfun(@plus, cellArray?????, {50, 50}, 'UniformOutput', false);

Answer 1

You can write a custom function add_val2(x, y), which adds y to the field x.val2, and call cellfun() with @add_val2 instead of @plus.

First, create the function add_val2.m:

function x = add_val2(x, y)
    x.val2 = x.val2 + y;
end

Then, calling cellfun() is as simple as

out = cellfun(@add_val2, cellArray, {50, 50}, 'UniformOutput', false);

which results in

>> out{1}
ans = 
  struct with fields:
    val1: 10
    val2: 70

>> out{2}
ans = 
  struct with fields:
    val1: 1000
    val2: 2050