Conflicts between variable and function name
Matlab provides some predefined functions such as pi, ans, i, j, clock, date, eps which cannot be used as variable names as they can create confliction between variable name and functions name. Usually, variable names take precedence over function names that result in unexpected results.
To check whether a variable name is already used with function:
Example:
Matlab
% MATLAB code for check if there is no % existing variables or functions name. In case it exists, % remove the variable from the memory with the clear() function. exist varname |
Output:
ans=0
genvarname()
This function (generate variable name) is used to construct a valid and unique variable name. It returns an array of strings or characters that can be used as a legal variable name. Argument str can be a string, a string array, a character array, or a cell array containing character vectors. All the returned elements are unique.
Syntax:
varname = genvarname(str)
varname = genvarname(str, exclusions)
here genvarname(str, exclusions) returns a legal variable name that is different from any name listed in the exclusions input. The argument exclusions can be a string, a string array, a character array, a cell array of character vectors.
Example 1:
Matlab
% MATLAB code for gemvarname() var_name = genvarname({'Pen', 'Pen', 'Pen', 'Pen'}) |
Output:
var_name = 1X4 cell 'Pen_1' 'Pen_2' 'Pen_3' 'Pen_4'
Example 2:
Matlab
% MATLAB code for genvarname() with different parameters a = ["Pen", "Eraser", "Pencil", "Box" ] var_name=genvarname(a,"Box") |
Output:
var_name= 1x4 string "Pen" "Eraser" "Pencil" "Box1"
Variable Names in MATLAB
A variable is a named-memory location that stores different types of data which can be used to perform a specific set of operations. It can be thought of as a container that holds some value in memory. The Matlab workspace store all the variables being used during a session. This workspace not only deals with the creation of new variables but also supports the reusing of existing variables in the execution of the command. Each variable in the Matlab environment is treated as a matrix or an array of different data types. In Matlab, variables are assigned using the assignment ‘=’ operator.
Note:
- After the creation of a variable, we can use it later in our program.
- There must have values assigned to variables before they are used.
- If an expression returns a result without being assigned to any variable, the system implicitly assigns and stores the value to a special variable named ‘ans’. But ans variable is specific to the current workspace and the value of ans can change frequently, that is why the use of ans in a script or function is not recommended.
Example 1:
Matlab
% MATLAB code for defining a and initializing % it with a value 10 using assignment operator '=' a = 10 |
Output:
a = 10
Example 2:
Matlab
% MATLAB code for calculates an expression % and stores value 13 in variable b b = sqrt(169) |
Output:
b = 13
Example 3:
Matlab
% MATLAB code to stores the expression % in special variable 'ans' sqrt(169) |
Output:
ans = 13