What is Python? High-level programming language. How Python works

Application software development, including games

Scientific research

1. SciPy is an open source library of high quality scientific tools for the Python programming language. SciPy contains modules for optimization, integration, special functions, signal processing, image processing, genetic algorithms, ordinary differential equations, and other problems commonly found in science and engineering.
2. Matplotlib- a library in the Python programming language for visualizing data with two-dimensional (2D) graphics (3D graphics are also supported). The resulting images can be used as illustrations in publications.
3. Numpy is an extension to the Python language that adds support for large multidimensional arrays and matrices, along with a large library of high-level math functions for manipulating these arrays.

Education

Criticism of the Python language

Python is one of the slowest programming languages

GIL interferes with concurrent execution of multiple threads

No good distribution tools

Additional Information

The program is a set of algorithms that ensure the execution of the necessary actions. Conventionally, in the same way, you can program an ordinary person by writing precise commands in order, for example, to make tea. If the latter option uses natural speech (Russian, Ukrainian, English, Korean, etc.), then a special programming language will be needed for the computer. Python is one of those. The programming environment will subsequently translate the commands into and the person's purpose for which the algorithm was created will be fulfilled. Python has its own syntax, which will be discussed below.

History of the language

Development began in the 1980s and ended in 1991. The Python language was created by Guido van Rossum. Although the main symbol of "Python" is the snake, it was named after the American comedy show.

When creating the language, the developer used some commands borrowed from existing Pascal, C and C ++. After the first official version went online, a whole group of programmers joined in to refine and improve it.

One of the factors that allowed Python to become quite famous is design. He is recognized as one of the best by many highly successful specialists.

Features of "Python"

The Python programming language for beginners is a great teacher. It has a fairly simple syntax. It will be easy to understand the code, because it does not include many auxiliary elements, and the special structure of the language will teach you how to indent. Of course, a well-designed program with few commands will be immediately understandable.

Many syntax systems have been built around object-oriented programming. Python is no exception. For what exactly was he born? It will facilitate training for beginners, help to remember some of the elements of already qualified employees.

Language syntax

As already mentioned, the code is easy and simple to read. "Python" has sequential commands that are distinguished by the clarity of execution. In principle, the operators used will not seem difficult even for beginners. This is what makes Python different. Its syntax is light and simple.

Traditional operators:

• When setting a condition, use the if-else construction. If there are too many such lines, you can enter the elif command.
• Class is for understanding the class.
• One of the simpler operators is pass. It doesn't do anything, it fits for empty blocks.
• Loop commands are while and for.
• Function, method and generator are defined thanks to def.

In addition to single words, the Python programming language allows you to use expressions as operators. By using string chaining, you can reduce the number of individual commands and parentheses. The so-called lazy calculations are also used, that is, those that are performed only when the condition requires it. These include and and or.

The process of writing programs

The interpreter works on a single mechanism: when writing a line (after which "Enter" is placed), it is immediately executed, and a person can already see some result. This is useful and convenient enough for beginners or those who want to test a small piece of code. In compiled environments, you would first have to write the entire program, only then run it and check for errors.

The Python programming language (for beginners, as it has already become clear, it is ideal) in the Linux operating system allows you to work directly in the console itself. You should write the name of the code "Python" in English on the command line. It won't be difficult to create your first program. First of all, it should be borne in mind that you can use the interpreter here as a calculator. Since young and novice specialists are often not friendly with syntax, the algorithm can be written as follows:

After each line it is necessary to put "Enter". The answer will be displayed immediately after clicking it.

Data used by Python

There are several types of data used by computers (and programming languages), and this is quite obvious. Numbers can be fractional, whole, can consist of many digits, or be quite massive because of the fractional part. To make it easier for the interpreter to work with them, and he can understand what he is dealing with, a specific type should be set. Moreover, it is necessary so that the numbers fit into the allotted memory cell.

The most common data types used by the Python programming language are:

• Integer. We are talking about whole numbers that have both negative and positive values. Zero is also included in this type.
• In order for the interpreter to understand that it is working with fractional parts, the type should be set to float point. As a rule, it is used in the case of using numbers with a varying point. It should be remembered that when writing a program, you must adhere to the notation "3.25", and not use the comma "3.25".
• In the case of adding strings, the Python programming language allows you to add the string type. Often, words or phrases are enclosed in single or

Disadvantages and Benefits

In the past few decades, people have been more interested in how to spend more time mastering the data and less time getting it to be processed by the computer. A language about which there are only positives is the highest code.

There are practically no flaws in Python. The only serious drawback is the slowness of the algorithm execution. Yes, if you compare him with "C" or "Java", he is, frankly, a turtle. This is explained by the fact that this

The developer has taken care of adding the best in Python. Therefore, when using it, you will notice that it has absorbed the best features of other higher programming languages.

In the event that the idea implemented by the interpreter is not impressive, then it will be possible to understand this almost immediately, after writing several dozen lines. If the program is good, then the critical section can be improved at any time.

Nowadays, more than one group of programmers is working on improving Python, so it is not a fact that the code written in C ++ will be better than the one created using Python.

Which version is best to work with?

Now two versions of such a syntax system as the Python language are widely used at once. For beginners, the choice between them will be difficult enough. It should be noted that 3.x is still under development (although released to the masses), while 2.x is a fully finalized version. Many people advise using 2.7.8, as it practically does not lag and does not get confused. There are no radical changes in the 3.x version, so at any time your code can be transferred to the programming environment with an update. To download the required program, you should go to the official website, select your operating system and wait until the download is complete.

Want to get into the programming world and quickly write your first few programs? Or are you dreaming of learning new languages ​​but don't know where to start? Take a look at courses on the basics of Python programming. Read on for details on why this particular language is recommended for beginners and what programs you can create with it.

Python Fundamentals for Beginner Programmers

Python is a powerful high-level object-oriented programming language created by Guido van Rossum. It has an easy-to-use syntax, making it an ideal language for those trying to learn programming for the first time. To continue your acquaintance with the language, you can read the book by Dmitry Zlatopolsky "Python - programming basics". But we'll start with the very basics. There is a lot of literature in this area. Another option is Harry Percival's books “Python. Test Driven Development ”. It tells about the language from a practical point of view.

Using the language in practice

So, what is written in Python or "Python", as it is also called among programmers, and why learn it? Python is a general purpose language. It is used to write web applications using various frameworks, system utilities and applications to automate various actions. Courses on the basics of programming in Python are now enough to try to learn the language on your own.

This could be the backbone of a new profession, as it has a wide range of applications from web development, scientific and mathematical computing to desktop graphical user interfaces. It also works well for prototyping. That is, first a prototype is created in Python, then the concept can be transferred to faster and more compiled programming languages. Using this language, you can create desktop applications with a graphical interface and write games, for which there is a special library. The basics of algorithms and programming in Python are suitable for creating applications for mobile devices.

Why learn Python

Python also uses very simple and concise syntax and dynamic typing. Knowledge of the basics of algorithms and programming in Python allows you to quickly create a program and run it. If you need a language to quickly build applications and scripts in multiple areas, you will have a hard time finding a better alternative than Python. It has a number of obvious advantages over other programming languages:

• universal use - different types of applications can be written in this language, therefore, along with its development, there are wide opportunities for using this language;
• simplicity - the language was originally developed to simplify a person's work with it;
• popularity among programmers and demand in the labor market - Python is widely used in various projects;
• a large number of available libraries expand the capabilities of the language and make it even more universal;
• cross-platform - once written program will work on any platform where there is a language interpreter;
• one of the important advantages of the language is its high-quality documentation.

Python is also one of the oldest web development languages ​​created by Guido van Rossum at the National Research Institute of Mathematics and Computer Science in the Netherlands in the early 90s. The language is heavily borrowed from C ++, C and other scripting languages. It uses English keywords, which make up a lot of Python programming. If you master them, then you can assume that for the most part you have already mastered the language. This will take some time and you will need to understand the basic concepts before starting. So let's start by getting to know them.

Benefits of Python

One of the key benefits of Python programming is its interpretive nature. This means that the program code is not compiled into an executable file, but is executed by the interpreter every time it is started by the user. Therefore, to run the program, you must have it on the computer where you will create the programs. The interpreter and standard library are available in binary or source form from the Python website and can run smoothly on all major operating systems.

So, the main advantages of Python include:

Python is a great choice as it supports application development, from games to browsers to word processing.

How to install and run the interpreter

In order to start writing in Python, you need to download and install its interpreter on the official website of the language, choosing the version for your operating system. It is worth noting that there are two branches of the language - the second and the third. It's best to start learning the basics of Python 3 if you haven't installed a different version yet. When installing on Windows, be sure to pay attention to whether the Add Python to Path option and the Pip utility are enabled. Once installed, you can run it. To do this, on the command line, you need to enter: "python", and it will start. Three angle brackets appear in the window, indicating that you are in the interpreter. This programming language is also freely redistributable, and you can find tips, third-party tools, programs, modules and additional documentation for it.

Keywords in Python

In the interpreter, you can perform actions in the language interactively. Each action is performed immediately after pressing Enter. You can use it as an advanced calculator. But writing a large program in the interpreter is too time consuming. Therefore, it makes sense to use text editors. The finished text file can then be executed by the interpreter. One of the basics of Python is that any blocks in it are indented, so you need to indent to run the block and delete it. The interpreter can be easily extended with new data types or functions in C ++ or C. The Python programming language acts as an extension for custom applications. What makes this language so easy to learn is the fact that it uses English keywords rather than punctuation marks and has fewer syntactic constructs than other programming languages.

Getting started with Python

Before starting outside the interpreter, to create a program, you need to open a text editor and create an empty file with utf-8 encoding and set the extension “py”. It is best to use special code editors for programmers for this purpose. In the first line, you need to indicate the encoding. Lines starting with a # sign are considered comments and are not executed. Python is implicitly and dynamically typed, so you don't need to declare variables. Types are enforced and variables are also case sensitive, so var and VAR are treated as two separate variables. If you want to know how an object works, you just need to enter the following: “help (object)”. You can also use the dir (object) command to find out all the methods of a particular option, and you can use the __ doc__ object to find out its docstring.

How to run a written program

You must also run the written program on the command line. To do this, you need to write the name of the interpreter and, separated by a space, the name of the file with the written program. When starting the program, you must specify the full path to the file. This is not always easy, as the path can be very long, so sometimes it is easier to change the current directory on the command line and start the interpreter there. To do this, go to the desired directory, hold down the shift key, right-click on the directory and select the option “open command window” in the menu that opens. Then the command line will be launched in this directory. Next, in the console window, you need to enter the name of the interpreter and, separated by a space, the name of the file that is in it.

Language syntax

The basics of programming using Python as an example are not very different from other languages, but variables have a slightly different meaning. Python has no required characters to complete statements. Any blocks are indented, so you must back out to run the block and remove it. For multi-line comments, you must use multi-line lines. Values ​​are assigned using the “=” sign, and equality testing is performed with two of them “==”. You can increase or decrease values ​​using the = or - = operators with the sum on the right. This can work with strings and other data types. You can also use multiple variables on one line.

Data types in Python

Now let's look at data types. Python is based on data structures - dict, tuples, and lists. Kits can be found in the Kits Library, which are available in all versions of Python. Lists are like one-dimensional arrays, although you can have lists of other lists as well. Dictionaries are essentially associative arrays or hash tables. Tuples are one-dimensional arrays. Now, Python-based arrays can be of any type, and ypes is always zero. Negative numbers start from end to beginning, and -1 is the last element. Variables can also point to functions.

Strings in Python

Python strings can use single or double quotes, and you can use quotes of one kind in a string using a different kind. Multiline strings are enclosed in single or triple double quotes. To fill strings with values, you can use the modulo (%) operator followed by a tuple. Each% is replaced with a tuple element from left to right, and you can use dictionary substitutions as well. Python flow control statements are “while”, “for” and “if”. For branching, you need to use “if”. Use “for” to enumerate through a list. Use a range to get a list of numbers.

Functions in Python

The def keyword is used to declare functions. Binding another object to a variable removes the old one and replaces the immutable types. Optional arguments can be specified in the function declaration after the required arguments, giving them default values. In the case of named arguments, the argument name is assigned a value. Functions can return a tuple, and you can efficiently return multiple values ​​using tuple unboxing. Parameters are passed via reference, but tuples, ints, strings and other immutable types are immutable because only the memory location of the element is passed.

You have just started your acquaintance with the language, so do not be afraid of mistakes and refer to the available resources to continue learning this interesting and useful programming language.

A couple of decades ago, programmers seemed like some kind of shamans who knew what was inaccessible to others. Sometimes people learned programming "on their knees", scribbling a code on a piece of paper, because "the concentration of computer devices per capita" was extremely low. Now it is difficult to find a person who does not have a stationary computer or laptop at home. Learning technologies are also moving forward.

A bit of history

The Python programming language began to be developed by Guido van Rossum in the late eighties. Guido was a fellow at the Dutch CWI at the time. He wrote this language at his leisure, putting in some ideas on the ABC language, in which he was involved.

The name of the language was not at all in honor of the reptile. In fact, the idea for the name was a popular 70s British comedy show called Monty Python's Flying Circus, although Python is still much more often compared to a snake, as even the emblem on the official website says (it shows two snake heads).

It's not just van Rossum's design intuition that is considered the reason why the Python programming language is so popular. Learning from scratch becomes enjoyable and easy when you consider the presence of a friendly user community.

Not so long ago, in 2008, the first version of Python 3000 (3.0), which had been tested for a long time, was released, where many architectural flaws were eliminated. At the same time, the developers tried to maintain compatibility with previous versions of the language. Although there is a more recent version, both branches (2.x and 3.x) are supported.

Concise programming language

Python has several advantages over other languages. It is understandable almost intuitively, has a "transparent" syntax. This means that the program code in this language is much easier to read, which reduces the time not only for writing it, but also for various modifications and checks.

Of course, an "old school" programmer will say that you definitely need to know several languages, or you can even start by learning machine code. But after taking a course in programming in the Python language, a person will receive not only specific knowledge, but also the opportunity to realize their creative nature, creating applications and useful programs for themselves. Perhaps, soon programming will be necessary as well as knowledge of a foreign language.

Self-doubt

It's worth dropping the misconception that programming is hard. No, programming is much more interesting than it sounds; other activities and the so-called "lack of time" or laziness can interfere.

Basic literature will help you quickly learn Python programming. The curriculum should start by reading two books from which you can learn the basics. The first is Python Programming by Mark Lutz and the second is Python 3 Programming by Mark Summerfield. Lutz's book describes in detail, sometimes even too much, all the basic principles on which the language is built. Some advise reading Mark Lutz not for mastering, but for deepening basic knowledge. Summerfield's book explains everything more succinctly, the author does not frighten the reader with any difficulties. There is other literature, but these textbooks are the most useful and informative.

Introductory course

Let's remember elementary school. As a rule, even a child comes to the first grade with some minimal knowledge: his parents worked with someone, someone went to zero. The same goes for training in the Python programming language. It is really convenient and "transparent", but without a minimum knowledge of the basic principles of the programs, training will be difficult. It's like learning notes without hearing the music. Therefore, those who have never encountered programming at all should familiarize themselves with the "introductory minimum".

The CS50 lectures will be helpful. This is a Harvard University course on programming in Java Script, but the first lectures explain the interaction of a computer and programs in general in an accessible and understandable way. A Russian-speaking user has access to video recordings of this course with translation, additional materials, text versions of lectures and practical exercises. The video can be found almost anywhere, for example, on YouTube, but all the material in its entirety is on the Java Script site.

In the Internet

The Python programming language is gaining popularity, so there have been several portals for a long time, on which there are many materials for self-study. For example, "Python 3 for Beginners". This site has a lot of material for beginners, you can use it as a cheat sheet. There is also a large amount of information on this topic with free access on the Codecademy website.

Communication on the forums is also important. Learning alone is always more difficult, so don't neglect the different communities.

Paid courses

You can always use paid courses, but sometimes it costs a lot of money, and the result may be unsatisfactory. Therefore, it is of course advisable to choose courses that offer a free orientation assignment. For example, there is an intensive course on "Fundamentals of Python Programming" at GeekBrains. The lesson is free, held every ten days. To sign up, you need to log in to the site.

Tip: whichever course you choose, first familiarize yourself with the basics of the language, so as not to waste time on what you can easily learn yourself. It will be enough to read the above books.

Of course, when the theory is mastered, you want to practice. Nick Parlante's lectures should be mentioned here. They are in English, although in general there is a lot of good educational literature in English, and this should not be surprising. In his lectures, Nick not only teaches the Python programming language, but also gives excellent practical problems.

Usage

The Python programming language has been used to create many applications that many people use on a daily basis. For example, this is the sixth version of the BitTorrent torrent client. Also "Python" ("Python") is used in the raster graphics editor Gimp. With the help of it, additional modules, filters, for example, are created. Much of Civilization IV and Batterfield 2 are written in this language.

Python is used by such companies as Google, Facebook, Instagram, Dropbox, and Pinterest. It also runs in the core of the Yandex Disk application. About 10% of the company's employees write in Python, and many programmers call it their favorite language.

How to get started

No code can work "in the air"; the Python programming language also obeys this rule. Although training from scratch begins with theory, in fact, one might say, it begins with the installation of a working environment on a personal computer. How to do it? It's simple: you need to follow the link on the official Python website, download and run the installer, and then carefully follow the steps it suggests.

Please note that you need to download a file suitable for the operating system installed on your computer!

If the installation was successful, open a console (as a rule, this can be done with the keyboard shortcut "ctrl + alt + T"). Now you can write your first program. For example, enter "python3". If the console displays a "greeting", where the program version is indicated (for example, 3.4.0), then everything is in order, if not, then you need to install the third version of "Python" with the command: "sudo apt-get install python3".
However, this is not required. You can write code in any convenient text editor and then run it through the console, or you can use the IDLE development environment that comes with the distribution kit.

Start IDLE. It takes just one line of code to create a tiny program.

print ("Hello world!")

Enter this code into the IDLE window and press Enter. The environment will instantly respond with an action - it will display the required text on the screen. The first program is ready.