Valid Names

A valid variable name starts with a letter, followed by letters, digits, or underscores. MATLAB^® is case sensitive, so A and a are not the same variable. The maximum length of a variable name is the value that the namelengthmax command returns.

You cannot define variables with the same names as MATLAB keywords, such as if or end. For a complete list, run the iskeyword command.

Conflicts with Function Names

Avoid creating variables with the same name as a function (such as i, j, mode, char, size, and path). In general, variable names take precedence over function names. If you create a variable that uses the name of a function, you sometimes get unexpected results.

Check whether a proposed name is already in use with the exist or which function. exist returns 0 if there are no existing variables, functions, or other artifacts with the proposed name. For example:

exist checkname

ans =
     0

If you inadvertently create a variable with a name conflict, remove the variable from memory with the clear function.

Another potential source of name conflicts occurs when you define a function that calls load or eval (or similar functions) to add variables to the workspace. In some cases, load or eval add variables that have the same names as functions. Unless these variables are in the function workspace before the call to load or eval, the MATLAB parser interprets the variable names as function names. For more information, see: