#Python sleep code#

This function call itself may have more or less precision than you require. The time.sleep() function calls a system function to block the calling thread. It may decide to let the thread block for a little longer before waking it up and allowing it to resume execution (e.g. This is because the underlying operating system decides what threads should run and when to run them.

… the suspension time may be longer than requested by an arbitrary amount because of the scheduling of other activity in the system. The calling thread will block for at least the specified number of seconds, but may block for longer. This may happen if the user presses Ctrl-C to send a SIGINT (signal interrupt) to the process that owns the thread, which by default will terminate the process. The actual suspension time may be less than that requested because any caught signal will terminate the sleep() following execution of that signal’s catching routine. The calling thread may block for less than the time specified, if the process is interrupted.

We may also call the time.sleep() function from a new thread used to execute a custom function. We may call the time.sleep() function from the main thread, which is the default thread in your progress. In concurrent programming we may want the current thread to block or sleep for a specified time.

Threading in Python: The Complete Guide.

You can learn more about Python threads in the guide: Python provides the ability to create and manage new threads via the threading module and the threading.Thread class.

#Python sleep code#

Sometimes we may need to create additional threads in our program in order to execute code concurrently. Both processes and threads are created and managed by the underlying operating system. Lastly, without time.sleep() or asyncio.sleep() below, first, test1() is run at once, then test2() is run at once: import asyncioĪwait asyncio.A thread is a thread of execution in a computer program.Įvery Python program has at least one thread of execution called the main thread. So, only 0 second is taken to run test1() and test2() in total: Test1 # 0 second So, 0 second is taken to run test1() and test2() in total: Test1 # 0 secondĪnd, with asyncio.sleep(0) below, test1() and test2() are run at once alternately: import asyncio So, only 3 seconds are taken to run test1() and test2() in total: Test1 # 1 secondĪnd, with time.sleep(0) below, first, test1() is run at once, then test2() is run at once: import asyncio With asyncio.sleep(1) below, test1() and test2() are run every one second alternately: import asyncio So, 6 seconds are taken to run test1() and test2() in total: Test1 # 1 second With time.sleep(1) below, first, test1() is run every one second, then test2() is run every one second: import asyncioĪwait asyncio.gather(test1(), test2()) # Here īecause time.sleep is blocking and the first call of hello() has to finish first before the second call of hello() starts running. In contrast, replacing the line await asyncio.sleep(1) with time.sleep(1), the output will be Hello. You can see that await asyncio.sleep(1) is not blocking the execution of the script. But when you call await asyncio.sleep(5), it will ask the event loop to run something else while your await statement finishes its execution. When time.sleep(5) is called, it will block the entire execution of the script and it will be put on hold, just frozen, doing nothing.

However, the main difference is that time.sleep(5) is blocking, and asyncio.sleep(5) is non-blocking. You aren't seeing anything special because there's nothing much asynchronous work in your code.