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Data that is stored in a cell array can be processed in several ways
depending on the actual data. The most simple way to process that data
is to iterate through it using one or more for
loops. The same
idea can be implemented easier through the use of the cellfun
function that calls a user specified function on all elements of a cell
array.
Evaluate the function named name on the elements of the cell array c. Elements in c are passed on to the named function individually. The function name can be one of the functions
isempty
- Return 1 for empty elements.
islogical
- Return 1 for logical elements.
isreal
- Return 1 for real elements.
length
- Return a vector of the lengths of cell elements.
ndims
- Return the number of dimensions of each element.
prodofsize
- Return the product of dimensions of each element.
size
- Return the size along the k-th dimension.
isclass
- Return 1 for elements of class.
Additionally,
cellfun
accepts an arbitrary function func in the form of an inline function, function handle, or the name of a function (in a character string). In the case of a character string argument, the function must accept a single argument named x, and it must return a string value. The function can take one or more arguments, with the inputs args given by c, d, etc. Equally the function can return one or more output arguments. For examplecellfun (@atan2, {1, 0}, {0, 1}) =>ans = [1.57080 0.00000]Note that the default output argument is an array of the same size as the input arguments.
If the param 'UniformOutput' is set to true (the default), then the function must return either a single element which will be concatenated into the return value. If 'UniformOutput is false, the outputs are concatenated in a cell array. For example
cellfun ("tolower(x)", {"Foo", "Bar", "FooBar"}, "UniformOutput",false) => ans = {"foo", "bar", "foobar"}Given the parameter 'ErrorHandler', then errfunc defines a function to call in case func generates an error. The form of the function is
function [...] = errfunc (s, ...)where there is an additional input argument to errfunc relative to func, given by s. This is a structure with the elements 'identifier', 'message' and 'index', giving respectively the error identifier, the error message, and the index into the input arguments of the element that caused the error. For example
function y = foo (s, x), y = NaN; endfunction cellfun (@factorial, {-1,2},'ErrorHandler',@foo) => ans = [NaN 2]See also: isempty, islogical, isreal, length, ndims, numel, size, isclass.
An alternative is to convert the data to a different container, such as
a matrix or a data structure. Depending on the data this is possible
using the cell2mat
and cell2struct
functions.
Convert the cell array c into a matrix by concatenating all elements of c into a hyperrectangle. Elements of c must be numeric, logical or char, and
cat
must be able to concatenate them together.See also: mat2cell, num2cell.
Convert cell to a structure. The number of fields in fields must match the number of elements in cell along dimension dim, that is
numel (
fields) == size (
cell,
dim)
.A = cell2struct ({'Peter', 'Hannah', 'Robert'; 185, 170, 168}, {'Name','Height'}, 1); A(1) => ans = { Height = 185 Name = Peter }