eval - Evaluate MATLAB expression - MATLAB (original) (raw)

• Documentation
• Examples
• Functions
• Apps
• Videos
• Answers

Main Content

Evaluate MATLAB expression

Syntax

Description

eval([expression](#mw%5Fda6cc3d7-b0f6-46b1-9e81-f9c96e554611)) evaluates the MATLAB® code in expression.

Note

Security Considerations: Before callingeval with untrusted user input, validate the input to avoid unexpected code execution. Examples of untrusted user input are data 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 eval. First, search for allowed operations. Then, if you find other operations, disallow execution.
• Replace eval with an alternative. For more information, see Alternatives to the eval Function.

Performance Considerations: In most cases, using theeval function is 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 toeval.

example

[[output1,...,outputN](#mw%5F0ff7b211-7176-42fa-9742-aa4189ef105c)] = eval([expression](#mw%5Fda6cc3d7-b0f6-46b1-9e81-f9c96e554611)) returns the outputs from expression in the specified variables.

example

Examples

collapse all

Use eval to evaluate and plot the expression magic(5).

Z = eval('magic(5)'); mesh(Z)

Input Arguments

collapse all

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: eval('magic(5)')

Output Arguments

collapse all

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

Limitations

• If you use eval within an anonymous function, nested function, or function that contains a nested function, the evaluatedexpression 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 eval function. For example, the statementeval(['output = ',expression]) is not recommended.
  Instead, specify output arguments to the eval function to store the results of the evaluated expression. For example:
  output = eval(expression)

Extended Capabilities

Version History

Introduced before R2006a