stw ⏱️

A lightweight Python stopwatch library for timing code execution with precision. Features include lap timing, function execution timing, and context manager support.

Docs can be found here.

Features

• Simple start/stop timing
• Lap timing with named laps
• Function execution timing
• Context manager support
• Elapsed time tracking
• Lap time analysis
• String representations for debugging

Installation

pip install stw

Usage

Basic Timing

from stw import Stopwatch

# Simple start/stop
sw = Stopwatch()
sw.start()
# ... your code here ...
elapsed = sw.stop()
print(f"Operation took {elapsed:.2f} seconds")

# Auto-start initialization
sw = Stopwatch(start=True)
# ... your code here ...
elapsed = sw.stop()

# Using context manager
with Stopwatch() as sw:
    # ... your code here ...
    print(f"Current time: {sw.elapsed_time():.2f}")

Lap Timing

sw = Stopwatch(start=True)

# Record named laps
lap_time, total_time = sw.lap("database_query")
lap_time, total_time = sw.lap("data_processing")

# Auto-named laps
lap_time, total_time = sw.lap()  # Named "lap 1"
lap_time, total_time = sw.lap()  # Named "lap 2"

# Get lap information
# By name
db_lap_time, db_total = sw.get_lap(name="database_query")

# By index
first_lap_time, first_total = sw.get_lap(index=0)

# Get time since last lap
time_since_last = sw.elapsed_since_lap()

# Get time since specific lap
time_since_db = sw.elapsed_since_lap("database_query")

Function Timing

from stw import Stopwatch

def expensive_operation(x, y, multiplier=1):
    # ... some time-consuming code ...
    return (x + y) * multiplier

sw = Stopwatch()

# Time function with arguments
time_taken, result = sw.time_function(
    expensive_operation, 
    2, 
    3, 
    multiplier=2
)
print(f"Function took {time_taken:.2f} seconds and returned {result}")

Advanced Usage

# Nested timing
with Stopwatch() as outer:
    # ... some code ...
    with Stopwatch() as inner:
        # ... nested operation ...
        inner_time = inner.elapsed_time()
    outer_time = outer.elapsed_time()

# String representation for debugging
sw = Stopwatch(start=True)
sw.lap("first")
print(sw)  # Outputs: Stopwatch(running=True, elapsed_time=0.001, elapsed_since_lap=0.001)

API Reference

Constructor

• Stopwatch(start=False): Create a new stopwatch instance
  • start: Whether to start timing immediately

Methods

• start(): Start the stopwatch
• stop() -> float: Stop the stopwatch and return total time
• lap(name=None) -> tuple[float, float]: Record a lap, returns (lap_time, total_time)
• get_lap(index=None, name=None) -> tuple[float, float]: Get lap timing by index or name
• elapsed_time() -> float: Get current total elapsed time
• elapsed_since_lap(name=None) -> float: Get time elapsed since specific lap
• time_function(func, *args, **kwargs) -> tuple[float, any]: Time a function execution

Properties

• is_running -> bool: Check if stopwatch is currently running
• laps -> list[tuple[str, float, float]]: Access recorded laps

Error Handling

The library raises appropriate exceptions for invalid operations:

• RuntimeError: When stopping/lapping before starting
• ValueError: When accessing invalid laps or providing invalid arguments

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

MIT License