python eval
时间: 2023-09-02 10:14:10 浏览: 53
The eval() function in Python is used to evaluate a string as a Python expression. It takes a string as an argument and returns the value of the expression. This function can be used to execute dynamically generated Python code, or to evaluate user input as Python code. However, it should be used with caution as it can be a security risk if used with untrusted input.
Syntax: eval(expression, globals=None, locals=None)
Parameters:
- expression: the string containing the Python expression to be evaluated.
- globals (optional): a dictionary containing global variables. If provided, the expression will be evaluated in the context of this dictionary.
- locals (optional): a dictionary containing local variables. If provided, the expression will be evaluated in the context of this dictionary.
Example:
```
x = 5
y = 10
expression = "x + y"
result = eval(expression)
print(result)
```
Output:
```
15
```
In this example, the eval() function evaluates the expression "x + y" as a Python expression and returns the result, which is the sum of x and y.