How do I measure elapsed time in Python?

There are several ways to measure elapsed time in Python. Here are three options:

1. time.perf_counter(): This function returns the current value of a performance counter, which is a high-resolution timer provided by the operating system. To measure elapsed time, you can call perf_counter() before and after the code that you want to measure, and then subtract the start time from the end time.

2. time.process_time(): This function returns the amount of time that the current process has spent executing in CPU time. Like perf_counter(), you can use this function to measure elapsed time by calling it before and after the code that you want to measure, and then subtracting the start time from the end time.

3. time.time(): This function returns the current time in seconds since the epoch (the epoch is a predefined point in time, usually the beginning of the year 1970). To measure elapsed time, you can call time() before and after the code that you want to measure, and then subtract the start time from the end time.

Here's an example of how you could use perf_counter() to measure the elapsed time of a piece of code:

import time

# Record the start time
start = time.perf_counter()

# Run the code that you want to measure
i = 1
for i in range(100000):
    i += 1

# Record the end time
end = time.perf_counter()

# Calculate the elapsed time
elapsed = end - start

print(f'Elapsed time: {elapsed:.6f} seconds')

You can use similar code to measure the elapsed time using process_time() or time(). Just replace perf_counter() with the appropriate function.