Function priority

         This topic introduces MATLAB  How to determine the function to be called when multiple functions in the current scope have the same name . The current scope includes the current file 、 Optional private subfolder relative to the currently running function 、 Current folder and MATLAB route .

MATLAB Use the following order of precedence ：

1. Variable

   Before assuming that the name matches the function ,MATLAB The variable with this name will be checked in the current workspace first .

   Be careful ： If you create a variable with the same name as the function ,MATLAB Cannot run this function , Until you clear the variable from memory .

2. Function or class whose name matches the name of the explicit import

   For with compound name （ That is, the name contains multiple parts 、 The parts are connected by points ） Function of ,import The function allows the function to be called using only the last part of the composite name . When the function name and explicit （ Non wildcard based ） When the imported functions match ,MATLAB Use the imported composite name , And make it take precedence over all other functions with the same name .

3. Nested functions within the current function

4. Local functions in the current file

5. Function or class whose name matches the name imported based on wildcard

   When the function name matches the function imported based on wildcard ,MATLAB Will use the imported composite name , And make it take precedence over all other functions with the same name , With the exception of nested and local functions .

6. Private functions

   The private function is named private Subfolders of （ That is, the folder directly below the folder where the currently running file is located ） The function in .

7. Object functions

   The object function accepts objects of a specific class in the form of a list of input parameters . If there are multiple object functions with the same name ,MATLAB Check the class of input parameters to determine the function to use .

8. @ Class constructor in folder

   MATLAB Use class constructors to create various objects （ for example timeseries or audioplayer）, You can also use object-oriented programming to define your own classes . for example , If you create a class folder @polynom And constructor @polynom/polynom.m, The constructor takes precedence over any location in the path named polynom.m Other functions of .

9. Loaded Simulink  Model

10. Functions in the current folder

11. Functions elsewhere in the path , According to the display order

When determining function priority in the same folder ,MATLAB Consider the file types in the following order ：

1. Built in functions

2. MEX function

3. Not loaded Simulink Model file , The order of file types is as follows ：

   1. SLX file

   2. MDL file

4. have .sfx Extended name Stateflow chart

5. Use MATLAB App Created by design tools App file (.mlapp)

6. with .mlx Program file with extension

7. P file （ With .p Coder file with extension ）

8. with .m Program file with extension

         for example , If MATLAB Find a with the same name in the same folder .m Document and P file , It USES P file . because P Files are not automatically regenerated , So make sure you're editing P Regenerate the file when the file .

​         To be sure MATLAB The function called on a particular input , Please be right  which  The function call includes the function name and input .

Change of function priority rule

         from R2019b Start ,MATLAB Changed name resolution rules , This affects variables 、 Nested function 、 Priority of local and external functions . You can refer to in the light of R2019b Changes to function priorities update code .

• Identifiers can only be used for one purpose within a function .

• Identifiers that are not explicitly declared may not be treated as variables

• Variables cannot be implicitly shared between parent and nested functions

• Change of compound name resolution priority

• Anonymous functions can contain both resolved and unresolved identifiers

import The behavior of the function has changed .

• The priority of import based on wildcard has changed

• A fully qualified import function cannot have the same name as a nested function

• A fully qualified import function masks the outer scope definition of the same name

• No error handling found during import

• Nested functions inherit from parent functions import sentence