evalc

Evaluate MATLAB expression and capture results

Syntax

results = evalc(expression)

[results,output1,...,outputN] = evalc(expression)

Description

results = evalc(expression) evaluates the MATLAB^® code represented by expression and captures anything that would normally be written to the Command Window in results.

Note

Security Considerations: When calling evalc with untrusted user input, validate the input to avoid unexpected code execution. Examples of untrusted user input are data coming from a user you might not know or from a source you have no control over. If you need to address this concern, consider these approaches:

• Validate inputs to evalc. First, search for allowed operations. Then, if you find other operations, disallow execution.

• Replace evalc with an alternative. For more information, see Alternatives to the eval Function.

Performance Considerations: In most cases, using the evalc function is also less efficient than using other MATLAB functions and language constructs, and the resulting code can be more difficult to read and debug. Consider using an alternative to evalc.

[results,output1,...,outputN] = evalc(expression) additionally returns the outputs from expression in the specified variables.

Examples

Evaluate Expression

Use evalc to evaluate the expression magic(5) and store the results.

results = evalc('magic(5)')

results =
    
    '
     ans =
     
         17    24     1     8    15
         23     5     7    14    16
          4     6    13    20    22
         10    12    19    21     3
         11    18    25     2     9
     
     '

Input Arguments

expression — Expression to evaluate

character vector | string scalar

Expression to evaluate, specified as a character vector or string scalar. expression must be a valid MATLAB expression and must not include any MATLAB keywords. To determine whether a word is a MATLAB keyword, use the iskeyword function.

Example: evalc('magic(5)')

Output Arguments

results — Captured Command Window output

character array

Captured Command Window output, returned as a character array. Individual lines in the captured output are separated by \n characters.

output1,...,outputN — Outputs from evaluated expression

any MATLAB data type

Outputs from evaluated expression, returned as any MATLAB data type.

Limitations

• When using evalc, the functions diary, more, and input are disabled.

• If you use evalc within an anonymous function, nested function, or function that contains a nested function, the evaluated expression does not create any variables.

Tips

• To allow the MATLAB parser to perform stricter checks on your code and avoid untrapped errors and other unexpected behaviors, do not include output arguments in the input to the evalc function. For example, the statement result = evalc(['output = ',expression]) is not recommended.

  Instead, specify output arguments to the evalc function to store the results of the evaluated expression. For example:

    [result,output] = evalc(expression)