Measures and prints the execution time of a wrapped function.

Inform the developer about how long a function call took to execute.

When quick profiling or debugging of function runtime is needed.

Used in debugging sessions, performance profiling, and educational examples of decorators.

decorator

def timer(func):\n def wrapper(*args, **kwargs):\n import time\n start = time.perf_counter()\n result = func(*args, **kwargs)\n elapsed = time.perf_counter() - start\n print(f'{func.__name__} executed in {elapsed:.4f} sec')\n return result\n return wrapper

func: callable to wrap; *args, **kwargs: arguments passed to the wrapped function.

• time.perf_counter
• functools.wraps
• print

• logging.info instead of print
• time.process_time for CPU time
• returning elapsed time instead of printing.

Forgetting to return the result; importing time inside the wrapper on each call; not preserving function metadata (__name__, __doc__).

context manager timer (using `with` statement); functools.lru_cache; timeit module.

Printing inside the wrapper can affect timing accuracy; for precise measurements prefer logging or the timeit module.

• py-decorator
• py-context-manager
• py-functools-wraps
• py-logging-decorator

Measures wall‑clock time; output goes to stdout; not suitable for production profiling without modification.

Provides immediate feedback on function runtime, useful for quick debugging and learning.

Think of a stopwatch wrapping a function call.

functools.wraps wrapper to preserve function metadata and docstring