Can You Extract Original Variable Names from Function Arguments in Python?

How to Extract the Original Variable Name from Arguments Passed to Functions

Consider the following scenario: you have a function that requires the name of a variable as an argument to perform some operations based on that name. Is there a way to obtain the original variable name within the function?

To answer this question, let's explore a method utilizing the inspect module that allows you to retrieve the calling context and extract the variable names from the code context.

<code class="python">import inspect

def foo(a, f, b):
    # Get the stack frame of the calling function
    frame = inspect.currentframe()
    
    # Move up one level to get the frame of the calling context
    frame = inspect.getouterframes(frame)[1]

    # Get the source code context of the calling context
    string = inspect.getframeinfo(frame[0]).code_context[0].strip()
    
    # Extract the argument names from the code context
    args = string[string.find('(') + 1:-1].split(',')
    
    names = []
    for i in args:
        if i.find('=') != -1:
            # Handle keyword arguments
            names.append(i.split('=')[1].strip())
        else:
            # Handle positional arguments
            names.append(i)
            
    print(names)

def main():
    e = 1
    c = 2
    foo(e, 1000, b = c)

main()</code>

Explanation:

1. inspect.currentframe() fetches the stack frame of the current function, which is foo() in this case.
2. inspect.getouterframes() navigates one level up in the calling context to get the frame of the calling function, main().
3. inspect.getframeinfo() retrieves the code context information for the acquired frame.
4. We isolate the argument list by parsing the code context, and then extract the names of the arguments, accounting for both positional and keyword arguments.
5. Finally, the list of original variable names is printed out.

Example Output:

['e', '1000', 'c']

Note: This approach involves inspecting the call stack and interpreting the source code context, which is fragile and prone to errors. It is not recommended for practical use and should only be considered for academic or entertainment purposes.

The above is the detailed content of Can You Extract Original Variable Names from Function Arguments in Python?. For more information, please follow other related articles on the PHP Chinese website!