Specific examples of Python built-in function locals

In Pythonlocals()Functions are used to get the dictionary of the current local symbol table. This dictionary contains local variables in the current scope.

Function definition

locals()The function does not require any parameters and returns the contents of the current local variable scope.

locals()

Basic usage

Use in functions

def my_function():
    a = 10
    b = 20
    local_variables = locals()
    print(local_variables)

my_function()
# Output: {'a': 10, 'b': 20}

Modify local variables (not recommended)

Although it can be usedlocals()Modify local variables, but this practice is usually not recommended as it can lead to unpredictable behavior.

def my_function():
    x = 10
    print('Before:', x)
    locals()['x'] = 20
    print('After:', x)

my_function()
# Output: Before: 10#       After: 10

Advanced Usage

Tracking local variables of functions

locals()Can be used to track local variables of functions, which is very useful during debugging.

def complex_function(a, b):
    result = a + b
    print(locals())

complex_function(5, 7)
# Output: {'a': 5, 'b': 7, 'result': 12}

Use in conjunction with decorators

Decorators can be combinedlocals()Use to check or modify local variables of the decorated function.

def debug(func):
    def wrapper(*args, **kwargs):
        local_vars = locals()
        print('Arguments:', local_vars)
        result = func(*args, **kwargs)
        print('Return Value:', result)
        return result
    return wrapper

@debug
def add(x, y):
    return x + y

add(3, 4)
# Output: Arguments: {'args': (3, 4), 'kwargs': {}}#       Return Value: 7

Things to note

• locals()The returned dictionary should not be modified; modifying it may not affect the value of the local variable.
• locals()When used at the module level,globals()same.

in conclusion

locals()It is a very useful built-in function in Python, especially when debugging and checking local variables in the current scope. Through the above routine, we can seelocals()Applications in actual programming and how to use it effectively to enhance the readability and debugging of the code.

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