Processing Data in Structures - Untitled
Description: Untitled

Previous: Manipulating Structures, Up: Data Structures

#### 6.1.4 Processing Data in Structures

The simplest way to process data in a structure is within a `for` loop (see Looping Over Structure Elements). A similar effect can be achieved with the `structfun` function, where a user defined function is applied to each field of the structure.

— Function File: structfun (func, s)
— Function File: [a, b] = structfun (...)
— Function File: structfun (..., 'ErrorHandler', errfunc)
— Function File: structfun (..., 'UniformOutput', val)

> Evaluate the function named name on the fields of the structure s. The fields of s are passed to the function func individually.

> `structfun` 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. If the function returns more than one argument, they are returned as separate output variables.

> 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 placed in a structure with the same fieldnames as the input structure.

>               s.name1 = "John Smith";
>               s.name2 = "Jill Jones";
>               structfun (@(x) regexp (x, '(\w+)$', 'matches'){1}, s,
>                          'UniformOutput', false)

> 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 (se, ...)

> where there is an additional input argument to errfunc relative to func, given by se. 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.

> See also: cellfun, arrayfun.

Alternatively, to process the data in a structure, the structure might be converted to another type of container before being treated.

— Built-in Function: struct2cell (S)

> Create a new cell array from the objects stored in the struct object. If f is the number of fields in the structure, the resulting cell array will have a dimension vector corresponding to `[`F`size(`S`)]`.

> See also: cell2struct, fieldnames.