A function is a block of reusable code that is used to perform a specific action. The advantages of using functions are:. Functions in Python are first-class citizens. It means that functions have equal status with other objects in Python. Functions can be assigned to variables, stored in collections, or passed as arguments. This brings additional flexibility to the language. There are two basic types of functions: built-in functions and user defined functions.
The built-in functions are part of the Python language; for instance dirlenor abs. The user defined functions are functions created with the def keyword. A function is created with the def keyword. The statements in the block of the function must be indented. The def keyword is followed by the function name with round brackets and a colon. The indented statements form a body of the function. The function is later executed when needed.
We say that we call the function. If we call a function, the statements inside the function body are executed. They are not executed until the function is called. The string at the top of the script is called the documentation string. It documents the current script.
The file in which we put Python code is called a module. We define two functions. The first function prints the module documentation string.
The second returns the path of the module.
What are the advantages/disadvantages of working in script mode in Python ?
Function may or may not return a value. If a funciton does not return a value, it implicitly returns None. Note that there are two underscores on both sides of the attribute.
Definitions of functions must precede their usage. Otherwise the interpreter will complain with a NameError. In the above example, we have two definitions of functions. One line is commented. A function call cannot be ahead of its definition. We can call the f2 only after its definition. Uncommenting the line we get a NameError. Functions can be defined inside a module, a class, or another function.
Function defined inside a class is called a method. Here the f function is defined inside another g function. It is an inner function.In this article, we will see the difference between the modes and will also discuss the pros and cons of running scripts in both of these modes.
Interactive mode, also known as the REPL provides us with a quick way of running blocks or a single line of Python code. The code executes via the Python shell, which comes with Python installation.
Interactive mode is handy when you just want to execute basic Python commands or you are new to Python programming and just want to get your hands dirty with this beautiful language. To access the Python shell, open the terminal of your operating system and then type "python". Press the enter key and the Python shell will appear.
This is the same Python executable you use to execute scripts, which comes installed by default on Mac and Unix-based operating systems. The result is immediately displayed on the Python shell as soon as the Python interpreter interprets the command. To run your Python statements, just type them and hit the enter key.
You will get the results immediately, unlike in script mode. For example, to print the text "Hello World", we can type the following:. We can also run multiple statements on the Python shell. A good example of this is when we need to declare many variables and access them later.
This is demonstrated below:. Using the method demonstrated above, you can run multiple Python statements without having to create and save a script. You can also copy your code from another source then paste it on the Python shell. The above example also demonstrates how we can run multiple Python statements in interactive mode.
The two print statements have been indented using four spaces. Just like in script mode, if you don't indent properly you will get an error. Also, to get the output after the last print statement, you should press the enter key twice without typing anything. You can also get help with regards to a particular command in interactive mode.
Just type the help command on the shell and then hit the enter key. You will see the following:. Now to find the help for a particular command, simple type that command, for instance, to find help for the print command, simply type print and hit the enter key. The result will look like this:.
As shown in the above output, the help utility returned useful information regarding the print command including what the command does and what are some of the arguments that can be used with the command.
To exit help, type q for "quit" and then hit the enter key. You will be taken back to the Python shell. If you need to write a long piece of Python code or your Python script spans multiple files, interactive mode is not recommended. Script mode is the way to go in such cases. In script mode, You write your code in a text file then save it with a. After writing your code, you can run it by clicking "Run" then "Run Module" or simply press F5.
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Let us create a new file from the Python shell and give it the name "hello. We need to run the "Hello World" program. Add the following code to the file:.
Other than executing the program from the graphical user interface, we can do it from the terminal of the operating system. However, you must be aware of the path to the directory where you have saved the file. Open the terminal of your operating system then navigate to the location of the file.When we want to choose a language for a project, we want to be thorough with what we can do with it.
We want to be aware of how it can help us be efficient at what we want to do, but we also want to be careful of the problems that can arise. So, we believe it is worthwhile to take out some time and find out more. Keeping you updated with latest technology trends, Join DataFlair on Telegram. But before that, I hope you all are aware of what features Python provides to us.
If not, first make yourself acquainted with the important features of Python. After that, it will be more easy for you to understand the advantages and disadvantages of Python. As we have seen earlier, Python can be extended to other languages.
This comes in handy, especially in projects. Complimentary to extensibility, Python is embeddable as well. This lets us add scripting capabilities to our code in the other language. Also, the fact that you need to write less and get more things done. Since Python forms the basis of new platforms like Raspberry Pi, it finds the future bright for the Internet Of Things.
This is a way to connect the language with the real world. But in Python, just a print statement will do. It is also quite easy to learnunderstandand code. This is why when people pick up Python, they have a hard time adjusting to other more verbose languages like Java. Because it is not such a verbose language, reading Python is much like reading English.
This is the reason why it is so easy to learn, understand, and code. It also does not need curly braces to define blocks, and indentation is mandatory.
This further aids the readability of the code. This language supports both the procedural and object-oriented programming paradigms. While functions help us with code reusability, classes and objects let us model the real world. A class allows the encapsulation of data and functions into one.
Like we said earlier, Python is freely available. But not only can you download Python for free, but you can also download its source code, make changes to it, and even distribute it.
It downloads with an extensive collection of libraries to help you with your tasks. Here, you need to code only onceand you can run it anywhere. However, you need to be careful enough not to include any system-dependent features. Lastly, we will say that it is an interpreted language. Since statements are executed one by one, debugging is easier than in compiled languages. Almost all of the tasks done in Python requires less coding when the same task is done in other languages.
This is the reason that many people suggest learning Python to beginners. Python is free therefore individuals, small companies or big organizations can leverage the free available resources to build applications.
Python is popular and widely used so it gives you better community support.Python has two basic modes: script and interactive. The normal mode is the mode where the scripted and finished. Interactive mode is a command line shell which gives immediate feedback for each statement, while running previously fed statements in active memory.
As new lines are fed into the interpreter, the fed program is evaluated both in part and in whole.Advantages and few disadvantages of python
On macOS or linux, open a terminal and simply type "python". If Python doesn't run, make sure it is installed and your path is set correctly. See Getting Python. In interactive mode what you type is immediately run. Python will respond with 2.
Interactive mode allows you to test out and see what Python will do. If you ever feel the need to play with new Python statements, go into interactive mode and try them out. However, you need to be careful in the interactive environment to avoid confusion. For example, the following is a valid Python script:. If you try to enter this as written in the interactive environment, you might be surprised by the result:. What the interpreter is saying is that the indentation of the second print was unexpected.
You should have entered a blank line to end the first i. For example, you should have entered the statements as though they were written:. Instead of Python exiting when the program is finished, you can use the -i flag to start an interactive session.
Advantages and Disadvantages of Python – How it is dominating programming world
Previous: Setting it up. Next: Self Help.Help Needed This website is free of annoying ads. We want to keep it like this. You can help with your donation: The need for donations Python In Greek mythology, Python is the name of a a huge serpent and sometimes a dragon. Python had been killed by the god Apollo at Delphi.
Python was created out of the slime and mud left after the great flood. The programming language Python has not been created out of slime and mud but out of the programming language ABC. It has been devised by a Dutch programmer, named Guido van Rossum, in Amsterdam. Origins of Python Guido van Rossum wrote the following about the origins of Python in a foreword for the book "Programming Python" by Mark Lutz in "Over six years ago, in DecemberI was looking for a "hobby" programming project that would keep me occupied during the week around Christmas.
My office a government-run research lab in Amsterdam would be closed, but I had a home computer, and not much else on my hands. I chose Python as a working title for the project, being in a slightly irreverent mood and a big fan of Monty Python's Flying Circus.
You can help with your donation: The need for donations Job Applications Python Lecturer bodenseo is looking for a new trainer and software developper. You need to live in Germany and know German. Find out more!
CSS-help needed! We urgently need help to improve our css style sheets, especially to improve the look when printing! Best would be, if we find somebody who wants to do it for free to support our website. But we could also pay something. Please contact usif you think that you could be of help! If you are interested in an instructor-led classroom training course, you may have a look at the Python classes by Bernd Klein at Bodenseo. With the Python interactive interpreter it is easy to check Python commands.
The Python interpreter can be invoked by typing the command "python" without any parameter followed by the "return" key at the shell prompt: python. Python comes back with the following information: Python 2. Oh yes, it can be written in a even simpler way.
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When I first started reading about Python, all of the tutorials have you use Python's Interactive Mode. It is difficult to save, write long programs, or edit your existing lines for me at least.
It seems like a far more difficult way of writing Python code than opening up a code. I am coming from a Java background, so I have ingrained expectations of writing and compiling files for programs. I also know that a feature would not be so prominent in Python documentation if it were not somehow useful.
So what am I missing? If you want to know how something works, you can just try it. There is no need to write up a file. I almost always scratch write my programs in the interpreter before coding them. It's not just for things that you don't know how they work in the programming language.
I never remember what the correct arguments to range are to create, for example, [-2, -1, 0, 1]. I don't need to. I just have to fire up the interpreter and try stuff until I figure out it is range -2, 2 did that just now, actually. Python is a very introspective programming language. If you want to know anything about an object, you can just do dir object. If you use IPython, you can even do object.
That's way faster than looking stuff up in documentation or even in code. Again, you have to use IPython highly recommendedbut you can time stuff. How often have you wanted to write a program to use once, and then never again. The fastest way to do this is to just do it in the Python interpreter.
Sure, you have to be careful writing loops or functions they must have the correct syntax the first timebut most stuff is just line by line, and you can play around with it. You don't need to put selective print statements in code to see what variables are when you write it in the interpreter. Nice again to see if you constructed something correctly.
The building Python debugger pdb also uses the intrepeter functionality, so you can not only see what a variable is when debugging, but you can also manipulate or even change it without halting debugging. When people say that Python is faster to develop in, I guarantee that this is a big part of what they are talking about. As such, you can rapidly write and test small pieces of code, and assemble those pieces into a larger program.
You're talking about running Python in the console by simply typing "python"? That's just for little tests and for practicing with the language. It's very useful when learning the language and testing out other modules. Of course any real software project is written in. The Python interpreter is a least common denominator: you can run it on multiple platforms, and it acts the same way modulo platform-specific modulesso it's pretty easy to get a newbie going with.
The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. If I initialize a variable and just give the name of the variable without 'print' in interactive mode then it value will be printed, for example.
But if I do this in a script, neither the value gets printed nor any error is generated, for example consider the below code in a script example. If I execute this script a blank line gets printed and not the value. Why there is a difference in interactive mode and script mode output? It's a convenience feature. In a program, printing the value of every expression statement would more often just be awkward and require you to suppress the output manually, so you have to print things explicitly.
Python has two basic modes: normal and interactive. The normal mode is the mode where the scripted and finished. Interactive mode is a command line shell which gives immediate feedback for each statement, while running previously fed statements in active memory.
As new lines are fed into the interpreter, the fed program is evaluated both in part and in whole. Learn more. Python interpretation difference in interactive mode and script mode Ask Question. Asked 3 years, 4 months ago. Active 3 years, 4 months ago. Viewed 8k times. Manel Manel 3 3 silver badges 15 15 bronze badges. You need print a to print the value of a in a script.
The interpreter automatically prints it for ease of use. Active Oldest Votes. Can you explain the way that this happens. Juggernaut Juggernaut 1, 4 4 gold badges 17 17 silver badges 37 37 bronze badges. Sign up or log in Sign up using Google.
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