Python 5b – Sleep

What is sleep()?

Sometimes you want your program to wait before doing the next thing—perhaps to create suspense in a game, rate-limit API calls, or print a countdown. Python’s sleep() function (from the time module) pauses execution for a number of seconds.

Basic Pause with sleep()

Import the function and pass the number of seconds to wait:

from time import sleep

print("Hello!")
sleep(2)      # wait for 2 seconds
print("Goodbye!")

Using sleep() in a Loop (Timer)

Add a short delay on each iteration to print a friendly timer or countdown:

from time import sleep

for second in range(1, 11):
    print(second)
    sleep(1)   # 1-second interval

Let the User Choose the Delay

Prompt the user, then sleep for that many seconds:

from time import sleep

seconds = int(input("How many seconds should I sleep? "))
print("Going to sleep...")
sleep(seconds)
print("Waking up!")

Sleep Task – Slow Calculator

1. Greet the user.
2. Wait 3 seconds, then ask for the first number.
3. Wait another 3 seconds, then ask for the second number.
4. Pause for 2 seconds, print “Thinking…”, wait another 2 seconds, then print the sum.

from time import sleep

print("Welcome to the Slow Calculator!")
sleep(3)
num1 = int(input("Enter the first number: "))
sleep(3)
num2 = int(input("Enter the second number: "))
sleep(2)
print("Thinking...")
sleep(2)
print("The total is", num1 + num2)