How can you make a timer in python?
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Improve Article Save Article View Discussion Improve Article Save Article In this article, we will see how to create a countdown timer using Python. The code will take input from the user regarding the length of the countdown in seconds. After that, a countdown will begin on the screen of the format ‘minutes: seconds’. We will use the time module here. ApproachIn this project, we will be using the time module and its sleep() function. Follow the below steps to create a countdown timer:
Below is the implementation of the above approach Python3
Output: https://media.geeksforgeeks.org/wp-content/cdn-uploads/20200729151851/python-countdown-timer.webm In this example, you will learn to create a countdown timer. To understand this example, you should have the knowledge of the following Python programming topics:
Countdown time in Python
While many developers recognize Python as an effective programming language, pure Python programs may run more slowly than their counterparts in compiled languages like C, Rust, and Java. In this tutorial, you’ll learn how to use a Python timer to monitor how quickly your programs are running. In this tutorial, you’ll learn how to use:
You’ll also gain background knowledge into how classes, context managers, and decorators work. As you explore examples of each concept, you’ll be inspired to use one or several of them in your code, for timing code execution, as well as in other applications. Each method has its advantages, and you’ll learn which to use depending on the situation. Plus, you’ll have a working Python timer that you can use to monitor your programs! Python TimersFirst, you’ll take a look at some example code that you’ll use throughout the tutorial. Later, you’ll add a Python timer to this code to monitor its performance. You’ll also learn some of the simplest ways to measure the running time of this example. Python Timer FunctionsIf you check out the built-in
Python 3.7 introduced several new functions, like
First, you’ll use Example: Download TutorialsTo better compare the different ways that you can add a Python timer to your code, you’ll apply different Python timer functions to the same code example throughout this tutorial. If you already have code that you’d like to measure, then feel free to follow the examples with that instead. The example that you’ll use in this tutorial is a short function that
uses the
Then, you can import the package as You’ll store the example in a file named
When you run this example, your output will typically look something like this:
The code may take a little while to run depending on your network, so you might want to use a Python timer to monitor the performance of the script. Your First Python TimerNow you’ll add a bare-bones Python timer to the example with
>>>
In this example,
you made two calls to You can now add a Python timer to the example code:
Note that you call Now, when you run the example, you’ll see the elapsed time before the tutorial:
That’s it! You’ve covered the basics of timing your own Python code. In the rest of the tutorial, you’ll learn how you can wrap a Python timer into a class, a context manager, and a decorator to make it more consistent and convenient to use. A Python Timer ClassLook back at how
you added the Python timer to the example above. Note that you need at least one variable ( Throughout this tutorial, you’ll create and update
You can find more information about Understanding Classes in PythonClasses are the main building blocks of object-oriented programming. A class is essentially a template that you can use to create objects. While
Python doesn’t force you to program in an object-oriented manner, classes are everywhere in the language. For quick proof, investigate the >>>
>>>
In Python, classes are great when you need to model something that needs to keep track of a particular state. In general, a class is a collection of properties, called attributes, and behaviors, called methods. For more background on classes and object-oriented programming, check out Object-Oriented Programming (OOP) in Python 3 or the official docs. Creating a Python Timer ClassClasses are good for tracking
state. In a
A few different things are happening here, so take a moment to walk through the code step by step. In line 5, you define a The definition of When you call On the other hand, when you call Here’s how you use >>>
Compare this to the earlier example where you used Using the Python Timer ClassNow apply
Notice that the code is very similar to what you used earlier. In addition to making the code more readable,
Printing the elapsed time from Adding More Convenience and FlexibilitySo far, you’ve learned that classes are suitable for when you want to encapsulate state and ensure consistent behavior in your code. In this section, you’ll add more convenience and flexibility to your Python timer:
First, see how you can customize the text used to report the time spent. In the previous code, the text To add
Note that the default text, In
After this update to >>>
Next, assume that you don’t just want to print a message to the console. Maybe you want to save your time measurements so that you can store them in a database. You can do this by returning the value of Perhaps you want to integrate
Instead of using Here are two examples that show the new functionality in action: >>>
When you run these examples in an interactive shell, Python prints the return value automatically. The third improvement that you’ll add is the ability to accumulate time measurements. You may want to do this, for example, when you’re calling a slow function in a loop. You’ll add a bit more functionality in the form of named timers with a dictionary that keeps track of every Python timer in your code. Assume that you’re expanding
The code loops over the numbers from 0 to 9 and uses those as offset arguments to
One subtle issue with this code is that you’re measuring not only the time it takes to download the tutorials, but also the time Python spends printing the tutorials to your screen. This might not be that important because the time spent printing should be negligible compared to the time spent downloading. Still, it would be good to have a way to precisely time what you’re after in these kinds of situations. There are several ways that you can work around this without changing the current implementation of First, you’ll introduce a dictionary called Class variables can be accessed either directly on the class or through an instance of the class: >>>
In both cases, the code returns the same empty class dictionary. Next, you’ll add optional names to your Python timer. You can use the name for two different purposes:
To add names to your Python timer, you need to make two more changes to
Note that you use >>>
You can now revisit
Rerunning the script will give output similar to earlier, although now you’re only timing the actual download of the tutorials:
The final improvement that you’ll make to >>>
That last line is the default way that Python represents objects. While you can glean some information from it, it’s usually not very useful. Instead, it would be nice to see information like the name of In Python 3.7, data classes were added to the standard library. These provide several conveniences to your classes, including a more informative representation string. You convert your Python timer to a data class using the
This code replaces your earlier You need to annotate your variables to use a data class. You can use this annotation to add
type hints to your code. If you don’t want to use type hints, then you can instead annotate all variables with Here are a few notes about the
Your new >>>
Now you have a pretty neat version of Before ending this section, revisit the complete source code of
Using a class to create a Python timer has several benefits:
This class is very flexible, and you can use it in almost any situation where you want to monitor the time it takes for code to run. However, in the next sections, you’ll learn about using context managers and decorators, which will be more convenient for timing code blocks and functions. A Python Timer Context ManagerYour Python
Luckily, Python has a unique construct for calling functions before and after a block of code: the context manager. In this section, you’ll learn what context managers and Python’s Understanding Context Managers in PythonContext managers have been a part of Python for a long time. They were introduced by
PEP 343 in 2005, and first implemented in Python 2.5. You can recognize context managers in code by the use of the
The most common use of context managers is probably handling different resources, like files, locks, and database connections. The context manager is then used to free and clean up the resource after you’ve used it. The following example reveals the fundamental structure of >>>
Note that In this example, What does it mean that The context manager protocol consists of two methods:
In other words,
to create a context manager yourself, you need to write a class that implements
>>>
First, note how Next, notice how >>>
Finally, If an exception happens while the block is being executed, then your code calls >>>
You can see that Now you know what context managers are and how you can create your own. If you want to dive deeper, then check out Creating a Python Timer Context ManagerYou’ve seen how context managers work in general, but how can they help with timing code? If
you can run certain functions before and after a block of code, then you can simplify how your Python timer works. So far, you’ve needed to call Again, for
>>>
You should also note two more subtle details:
>>>
Note that Using the Python Timer Context ManagerNow
you’ll learn how to use the
You’re timing the call to
This code does virtually the same as the code above. The main difference is that you don’t define the extraneous variable Running the script should give a familiar result:
There are a few advantages to adding context manager capabilities to your Python timer class:
Using A Python Timer DecoratorYour
A better solution is to use Understanding Decorators in PythonA decorator is a function that wraps another function to modify its behavior. This technique is possible because functions are first-class objects in Python. In other words, functions can be assigned to variables and used as arguments to other functions, just like any other object. This gives you a lot of flexibility and is the basis for several of Python’s most powerful features. As a first example, you’ll create a decorator that does nothing:
First, note that >>>
The line To define more interesting decorators, you need to know about inner functions. An inner function is a function that’s defined inside another function. One common use of inner functions is to create function factories:
>>>
Instead you use >>>
Similarly, you can use inner functions to create decorators. Remember, a decorator is a function that returns a function:
This pattern is prevalent for defining decorators. The interesting parts are those happening inside the inner function:
Try it out! >>>
Multiplying a text string by a number is a form of repetition, so It feels a bit clunky to keep repeating >>>
The One of the few decorators defined in the standard library is >>>
Sometimes, decorated functions must have correct metadata.
With this new definition of >>>
Note that
To see more examples of how to define decorators, check out the examples listed in Primer on Python Decorators. Creating a Python Timer DecoratorIn this section, you’ll learn how to extend your Python timer so that you can use it as a decorator as well. However, as a first exercise, you’ll create a Python timer decorator from scratch. Based on the blueprint above, you only need to decide what to do before and after you call the decorated function. This is similar to the considerations about what to do when entering and exiting the context manager. You want to start a Python timer before calling the decorated function, and stop the Python timer after the call finishes. You can define a
Note how much >>>
Recall that you can also apply a decorator to a previously defined function: >>>
Because >>>
So far, you’ve used decorators as functions applied to other functions, but that’s not entirely correct. Decorators must be callables. There are many callable types in Python. You can make your own objects callable by defining the special >>>
Here, This gives you a way of adding decorator capabilities to the existing
You can now use >>>
Before rounding out this section, know that there’s a more straightforward way of turning your Python timer into a decorator. You’ve already seen some of the similarities between context managers and decorators. They’re both typically used to do something before and after executing some given code. Based on these similarities, there’s a mixin class defined in the standard library called
When you use Using the Python Timer DecoratorNext up, you’ll redo the
If you compare this implementation with the original implementation without any timing, then you’ll notice that the only differences are the import of However, the decorator still applies to the whole function. This means that your code is taking into account the time it takes to print the tutorial, in addition to the time it takes to download. Run the script one final time:
The location of the elapsed time output is a telltale sign that your code is considering the time it takes to print as well. As you see here, your code prints the elapsed time after the tutorial. When you use
However, decorators are not as flexible as context managers. You can only apply them to complete functions. It’s possible to add decorators to already defined functions, but this is a bit clunky and less common. The Python Timer CodeYou can expand the code block below to view the final source code for your Python timer:
The code is also available in the You can use the code yourself by saving it to a file named >>>
Note that the package name on PyPI is >>>
Apart from the name and some additional features,
This kind of Python timer is mainly useful for monitoring the time that your code spends at individual key code blocks or functions. In the next section, you’ll get a quick overview of alternatives that you can use if you want optimize your code. Other Python Timer FunctionsThere are many options for timing your code with Python. In this tutorial, you’ve learned how to create a flexible and convenient class that you can use in several different ways. A quick search on PyPI shows that there are already many projects available that offer Python timer solutions. In this section, you’ll first learn more about the different functions available in the standard library for measuring time, including why Using Alternative Python Timer FunctionsYou’ve been using
One reason for having several functions is that Python represents time
as a >>>
Python’s IEEE 754 prescribes a system where the density of numbers that you can represent varies. The closer you are to one, the more numbers you can represent. For larger numbers, there’s more space between the numbers that you can express. This has some consequences when you use a Consider >>>
A nanosecond is one-billionth of a second. Note that adding a nanosecond to >>>
Here, you notice that adding a nanosecond to The challenges with representing time as a >>>
Integers are unbounded in Python, so this allows >>>
Because There are two
functions in All these functions are monotonic except >>>
The results could be different on your system. PEP 418 describes some of the rationale behind introducing these functions. It includes the following short descriptions:
As you can tell, Estimating Running Time With timeitSay you’re trying to squeeze the last bit of performance out of your code, and you’re wondering about the most effective way to convert a list to a set. You want to compare using >>>
This test seems to indicate that the set literal might be slightly faster. However, these results are quite uncertain, and if you rerun the code, you might get wildly different results. That’s because you’re only trying the code once. You could, for instance, get unlucky and run the script just as your computer is becoming busy with other tasks. A better way is to use the
Finally, the IPython interactive shell and the Jupyter Notebook have extra support for this functionality with the >>>
Again, the measurements indicate that using a set literal is faster. In Jupyter Notebooks, you can
also use the Finding Bottlenecks in Your Code With Profilers
This command runs
To use
This output shows that the total runtime was 0.586 seconds. It also lists the ten functions where your code spent most of its time. Here you’ve sorted by cumulative time ( You can see that your code spends virtually all its time inside the The total time (
You can now see
that You can use You can also investigate certain functions. Check how much overhead
Luckily, For a more powerful interface into profile data, check out KCacheGrind. It uses its own data format, but you can convert data from
This command will convert The last option that you’ll try here for timing your code is Note that line profiling takes time and adds a fair bit of overhead to your runtime. A normal workflow is first to use Before you run the profiler, you need to tell it which functions to profile. You do this by adding a
Note that you don’t import Next, run the profiler using
This command automatically saves the profiler data in a file called
First, note that the time unit in this report is microseconds ( ConclusionIn this tutorial, you’ve tried several different approaches to adding a Python timer to your code:
You’ve also learned why you should prefer Now you can add Python timer functions to your own code! Keeping track of how fast your program runs in your logs will help you monitor your scripts. Do you have ideas for other use cases where classes, context managers, and decorators play well together? Leave a comment down below! ResourcesFor a deeper dive into Python timer functions, check out these resources:
How do you put a timer in Python?Approach. Step 1: Import the time module.. Step 2: Then ask the user to input the length of the countdown in seconds.. Step 3: This value is sent as a parameter 't' to the user-defined function countdown(). ... . Step 4: In this function, a while loop runs until time becomes 0.. Is there a timer in Python?time() for Timer? The time function in the Python time module returns a number of seconds that have passed since the last defined epoch. It returns seconds in the form of floating-point data type. The above example shows the floating-point value and number of seconds.
How does timer work in Python?Python timer functions
After every specified number of seconds, a timer class function is called. start() is a function that is used to initialize a timer. To end or quit the timer, one must use a cancel() function. Importing the threading class is necessary for one to use the threading class.
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