Python 3 language. How to run a written program
In this collection, we have collected the most useful books about the Python programming language that will help both beginners and experienced programmers learn.
Here you'll find materials for creating applications, as well as tutorials to help you become familiar with tools, master databases, and improve your professional skills.
Sections:
For beginners
The tutorial provides an excellent and internationally recognized introduction to the Python language. It will quickly teach you how to write efficient, high-quality code. Suitable for both beginner programmers and those who already have experience using other languages. In addition to theory, the book contains tests, exercises and useful illustrations - everything you need to learn Python 2 and 3. In addition, you will get acquainted with some advanced features of the language that not many specialists have yet mastered.
Python is a multi-paradigm cross-platform programming language that has recently become especially popular in the West and in large companies such as Google, Apple and Microsoft. Thanks to its minimalistic syntax and powerful core, it is one of the most productive and highly readable languages in the world.
After reading this book, you'll learn the basics of the language in a fast, fun way, then move on to exception handling, web development, SQL, data science, and Google App Engine. You'll also learn how to write Android apps and much more about the power that Python gives you.
Another award-winning Python book with 52 hand-picked exercises for language learning. Having analyzed them, you will understand how the language works, how to write programs correctly and how to correct your own mistakes. The following topics are covered:
- Setting up the environment;
- Code organization;
- Basic Mathematics;
- Variables;
- Lines and text;
- Interaction with users;
- Working with files;
- Loops and logic;
- Data structures;
- Software development;
- Inheritance and composition;
- Modules, classes and objects;
- Packages;
- Debugging;
- Test automation;
- Game development;
- Web development.
This book is intended for beginners to learn programming. It uses a very standard approach to learning, but a non-standard language 🙂 It's worth noting that this is more of a book about the basics of programming than about Python.
The book Python Programming for Beginners is a great place to start. It is a detailed guide written specifically for beginners who want to master this language. Once you've learned the basics, you'll move on to object-oriented programming and creating CGI scripts to process web form data, and learn how to create graphical windowed applications and distribute them to other devices.
With the help of this tutorial, you will be able to go through all the steps from installing an interpreter to launching and debugging full-fledged applications.
"Python Crash Course" is a capacious narrative about the Python language. In the first half of the book, you will become familiar with basic language concepts such as lists, dictionaries, classes, and loops, and learn how to write clean and well readable code. In addition, you will learn how to test your programs. The second half of the book asks you to put your knowledge into practice by writing 3 projects: an arcade game like Space Invaders, a data visualization application, and a simple web application.
This is a very handy pocket cheat sheet created for Python 3.4 and 2.7. In it you will find the most necessary information on various aspects of language. Topics covered:
- Built-in object types;
- Expressions and syntax for creating and processing objects;
- Functions and modules;
- OOP (we have a separate one);
- Built-in functions, exceptions and attributes;
- Operator overloading methods;
- Popular modules and extensions;
- Options command line and development tools;
- Hints;
- Python SQL Database API.
A book for learning Python with lots of practical examples.
Practical examples can also be found in our section. For example, read our guide on how to implement the zip function yourself.
The purpose of this book is to introduce the reader to popular tools and various coding guidelines accepted in the open source community. The basics of the Python language are not covered in this book, because it is not about that at all.
The first part of the book describes the various text editors and development environments that can be used to write Python programs, as well as many types of interpreters for various systems. The second part of the book introduces the coding style adopted in the open source community. The third part of the book contains short review many Python libraries that are used in most open source projects.
The main difference between this book and all other manuals for beginners in learning Python is that, in parallel with studying the theoretical material, the reader gets acquainted with the implementation of projects for various games. This way, the future programmer will be able to better understand how certain language features are used in real projects.
The book covers the basics of both the Python language and programming in general. An excellent book for your first introduction to this language.
For advanced
If you want to move to Python 3 or upgrade properly old code written in Python 2, then this book is for you. And also for you - on transferring a project from Python 2 to Python 3 without pain.
In the book you will find many practical examples in Python 3.3, each of which is discussed in detail. The following topics are covered:
- Data structures and algorithms;
- Lines and text;
- Numbers, dates and times;
- Iterators and generators;
- Files and read/write operations;
- Data coding and processing;
- Functions;
- Classes and objects;
- Metaprogramming;
- Modules and packages;
- Web programming;
- Competitiveness;
- System administration;
- Testing and debugging;
- C extensions.
As you read this book, you'll develop a web application while learning the practical benefits of test-driven development. You'll cover topics such as database integration, JS automation tools, NoSQL, web sockets, and asynchronous programming.
The book covers Python 3 in detail: data types, operators, conditions, loops, regular expressions, functions, object-oriented programming tools, working with files and directories, and frequently used standard library modules. In addition, the book also focuses on the SQLite database, the database access interface, and methods for retrieving data from the Internet.
The second part of the book is entirely devoted to the PyQt 5 library, which allows you to create applications with graphical interface in Python language. Here we consider tools for processing signals and events, managing window properties, developing multi-threaded applications, describing the main components (buttons, text fields, lists, tables, menus, toolbars, etc.), options for their placement inside the window, tools for working with databases data, multimedia, printing documents and exporting them in Adobe PDF format.
Your Python programs may work, but they can run faster. This practical guide will help you better understand the structure of the language, and you will learn to find bottlenecks in the code and increase the speed of programs that work with large amounts of data.
As the title suggests, the purpose of this book is to provide the most complete understanding of the Django web application development framework. Due to the fact that the book was published in Russian back in 2010, it discusses outdated version framework, Django 1.1. But still, the book is recommended for reading, since it can teach you the basics of Django. And there are practically no good books on this framework in Russian except this one.
Authors Adrian Golovaty and Jacob Kaplan-Moss take a closer look at the framework's components. The book contains a lot of material on developing Internet resources using Django - from the basics to such special topics as PDF and RSS generation, security, caching and internationalization. Before reading the book, it is recommended to master basic concepts web development.
Game development
"Making Games with Python & Pygame" is a book that is dedicated to the Pygame game development library. Each chapter provides the full source code for the new game and detailed explanations of the development principles used.
Book "Invent" Your Own Computer Games with Python" will teach you how to program in Python using game development as an example. Later games explore creating 2D games using the Pygame library. You will learn:
- use loops, variables and logical expressions;
- use data structures such as lists, dictionaries and tuples;
- debug programs and look for errors;
- write simple AI for games;
- create simple graphics and animations for your games.
Data Analysis and Machine Learning
Improve your skills by working with data structures and algorithms in a new way - scientifically. Explore examples of complex systems with clear explanations. The book suggests:
- Learn concepts such as NumPy arrays, SciPy methods, signal processing, fast Fourier transforms, and hash tables;
- get acquainted with abstract models of complex physical systems, fractals and Turing machines;
- explore scientific laws and theories;
- analyze examples of complex problems.
This book introduces Python as a tool for solving problems that require large-scale computation. The goal of this book is to teach the reader how to use Python's data mining stack to effectively store, manipulate, and understand data.
Each chapter of the book is devoted to a specific library for working with big data. The first chapter covers IPython and Jupyter, the second covers NumPy, and the third covers Pandas. The fourth chapter contains material about Matplotlib, the fifth - about Scikit-Learn.
"Python for Data Analysis" talks about in all possible ways data processing. The book is an excellent introduction to the field of scientific computing. Here's what you'll get to know:
- interactive IPython shell;
- library for numerical calculations NumPy:
- pandas data analysis library;
- library for plotting matplotlib.
You will also learn to measure data over time and solve analytical problems in many areas of science.
This book invites you to study various methods data analysis using Python. Here's what you'll learn after reading:
- manage data;
- solve data science problems;
- create high-quality visualizations;
- apply linear regressions to evaluate relationships between variables;
- create recommendation systems;
- process big data.
This is a guide in clear language explains processing principles natural languages. You will learn to write programs that can process large sets unstructured texts, gain access to rich data sets and become familiar with basic algorithms.
Other
If you've ever spent hours renaming files or updating hundreds of table cells, you know how exhausting it can be. Do you want to learn how to automate such processes? Automate the Boring Stuff with Python teaches you how to create programs that solve a variety of routine tasks in minutes. After reading, you will learn how to automate the following processes:
- search for specified text in files;
- creating, updating, moving and renaming files and folders;
- searching and downloading data on the Internet;
- updating and formatting data in Excel tables;
- splitting, merging and encrypting PDF files;
- sending letters and notifications;
- filling out online forms.
An excellent book with a minimum barrier to entry. It talks more about biology than about language, but it will definitely be useful to everyone working in this field. Equipped with a large number of analyzed examples of varying complexity.
This book covers the basics of programming a Raspberry Pi system. The author has already compiled many scripts for you, and also provided an intelligible and detailed guide to creating your own. In addition to the usual exercises, you are invited to implement three projects: the game "Hangman", an LED clock and a software-controlled robot.
"Hacking Secret Ciphers with Python" not only tells the history of existing ciphers, but also teaches you how to create your own programs for encrypting and breaking ciphers. An excellent book for learning the basics of cryptography.
Share useful books on Python in the comments!
Python- a powerful and easy-to-learn programming language. It provides convenient high-level data structures and a simple but effective approach to object-oriented programming. Python interpreted language. To run the written programs, you must have a CPython interpreter. The python interpreter and large standard library are freely available as source and binary files for all major platforms on the official website Python http://www.python.org and may be redistributed without restrictions. In addition, the site contains distributions and links to numerous third-party modules and detailed documentation.
The language has a clear and consistent syntax, thoughtful modularity and scalability, thanks to which the source code written in Python programs are easy to read. Language developers Python adhere to a certain programming philosophy called “The Zen of Python”. Its text is output by the interpreter using the import this command:
Translated it sounds like this:
- Beautiful is better than ugly.
- Explicit is better than implicit.
- Simple is better than complex.
- Complex is better than confusing.
- Flat is better than nested.
- Sparse is better than dense.
- Readability matters.
- Special cases are not special enough to break the rules.
- At the same time, practicality is more important than perfection.
- Mistakes should never be hushed up.
- If they are not clearly hushed up.
- When faced with ambiguity, resist the temptation to guess.
- There should be one - and preferably only one - obvious way to do this.
- Although it may not be obvious at first if you are not Dutch.
- Now is better than never.
- Although never is often better than right now.
- If the implementation is difficult to explain, the idea is bad.
- If the implementation is easy to explain, the idea is probably good.
- Namespaces are a great thing! We will make more of them!
Python is an actively developing programming language, new versions are released approximately every two and a half years. Due to this and some other reasons, Python There are no ANSI, ISO or other official standards; CPython takes over.
History of the creation of the language
Development of the Python language began in the late 1980s by an employee of the Dutch CWI Institute. Distributed OS Amoeba required extensibility scripting language for which Guido van Rossum created Python. The new language borrowed some developments from the ABC language, which was focused on teaching programming. In February 1991, Guido published the source text in the alt.sources newsgroup. The name of the language does not come from the type of reptile. The author named the language after the popular 1970s British comedy TV show Monty Python's Flying Circus. However, the emblem of the language is represented by snake heads. After extensive testing, the first version of Python 3.0 was released. Today both branches of development are supported (Python 3.x and 2.x).
Python was created under the influence of many programming languages: Modula-3, C, C++, Smalltalk, Lisp, Fortran, Java, Miranda, Icon. Although Python has a fairly distinctive syntax, one of the design principles of the language is the principle of least surprise.
Standard Library
The rich standard library is one of the attractions of Python. It provides tools for working with many network protocols and Internet formats. There are modules for working with regular expressions, text encodings, multimedia formats, cryptographic protocols, and archives. In addition to the standard library, there are many libraries that provide an interface to all system calls on different platforms.
For Python, the DB-API 2 database programming interface specification has been adopted and packages corresponding to this specification have been developed for access to various DBMSs: Oracle, MySQL, PostgreSQL, Sybase, Firebird (Interbase), Informix, Microsoft SQL Server and SQLite.
The NumPy library for working with multidimensional arrays allows you to achieve scientific calculation performance comparable to specialized packages. SciPy uses NumPy and provides access to a wide range of mathematical algorithms. Numarray is specifically designed for operations with large volumes of scientific data.
Python provides a simple and convenient software interface C API for writing your own modules in C and C++ languages. A tool like SWIG allows you to almost automatically obtain bindings for using C/C++ libraries in Python code. The ctypes standard library tool allows Python programs to directly access dynamic libraries, written in C. There are modules that allow you to embed C/C++ code directly into source files Python, creating extensions on the fly.
Python and the vast majority of libraries for it are free and supplied in source code. Moreover, unlike many open systems, the license does not restrict the use of Python in any way commercial developments and does not impose any obligations other than the indication of copyright.
Areas of application
Python is a stable and widespread language. It is used in many projects and various qualities: As a primary programming language or for creating application extensions and integrations. A large number of projects have been implemented in Python, and it is also actively used to create prototypes for future programs. Python is used by many large companies.
Python with the NumPy, SciPy and MatPlotLib packages is actively used as universal environment for scientific calculations as a replacement for common specialized commercial packages Matlab, IDL, etc.
Professional 3D graphics programs such as Houdini and Nuke use Python to extend standard features programs.
Sources
Presentations
Homework
Prepare messages:
- Python as a tool for scientists
- Python and Ruby (comparison)
- Python and WEB
- Creating windowed applications using Python and graphics libraries (wxPython, PyQt, PyGTK, etc.)
Just a couple of decades ago, programmers seemed like some kind of shamans who knew something that was inaccessible to others. Sometimes people learned programming on their knees, scribbling code on a piece of paper, because “concentration computer devices per capita" was extremely low. Now it is difficult to find a person who does not have a home desktop computer or laptop. Educational technologies also do not stand still.
A little history
The Python programming language began to be developed by Guido van Rossum in the late eighties. Guido was at the time an employee of the Dutch CWI Institute. He wrote this language in his spare time, putting into it some ideas about the ABC language, in which he participated in the work.
The tongue was not named after the reptile. In fact, the name was inspired by a popular British comedy show from the seventies called Monty Python's Flying Circus, although Python is still much more often compared to a snake, as evidenced by the logo on the official website (it features two snake heads).
Van Rossum's design intuition is not the only reason why the Python programming language is so popular. Learning from scratch becomes a pleasant and easy task, given the presence of a friendly community of users.
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 shortcomings were eliminated. At the same time, the developers tried to maintain compatibility with previous versions of the language. Despite the presence of a more recent version, both branches (2.x and 3.x) are supported.
Concise programming language
Python has a number of advantages over other languages. It is understandable almost intuitively and has a “transparent” syntax. It means that program code it is much easier to read in this language, 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, but you can even start by studying machine code. But by completing a programming course in Python, a person will receive not only specific knowledge, but also the opportunity to realize his creative nature by creating applications and useful programs. Perhaps soon programming will be as necessary as knowing a foreign language.
Diffidence
It is worth discarding the misconception that programming is difficult. No, programming is much more interesting than it seems; Other activities and the so-called “lack of time” or laziness can interfere.
Basic literature will help you quickly learn programming in Python. The training course should begin by reading two books from which you can glean 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 language is built. Some people advise reading Mark Lutz not for mastery, but for deepening basic knowledge. Summerfield's book explains everything more succinctly; the author does not frighten the reader with any complications. There are 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 first grade with some minimal knowledge: some were taught by their parents, others went to zero. Training in the Python programming language is also provided. It is really convenient and "transparent", but without minimal knowledge about basic principles training programs will be difficult. It's like learning sheet music 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 devoted to programming in Java Script, but the first lectures explain the interaction of the computer and programs in general in an accessible and understandable way. Russian-speaking users have access to video recordings of this course with translation, additional materials, text versions of lectures and practical assignments. The video can be found almost anywhere, for example, on YouTube, but all the materials in their entirety can be found on the Java Script website.
In the Internet
The Python programming language is gaining popularity, so for a long time there have been several portals with a lot of self-learning materials. For example, "Python 3 for Beginners." This site has a lot of materials for beginners; it can be used as a cheat sheet. There is also a large amount of information on this topic with free access on the Codecademy website.
Communication on forums is also important. Studying alone is always harder, so don't neglect different communities.
Paid courses
You can always use paid courses, but it sometimes costs a lot of money, and the result may be unsatisfactory. Therefore, it is of course advisable to choose courses that offer a free trial assignment. For example, there is an intensive course on “Python Programming Fundamentals” on GeekBrains. The class is free and held every ten days. To register, you must log in to the site.
Advice: Whatever courses you choose, first familiarize yourself with the basics of the language so as not to waste time on something that you can easily learn on your own. It will be enough to read the books mentioned above.
Of course, when the theory is mastered, you want to practice. Nick Parlante's lectures need to be mentioned here. They are in English, although in general a lot of good educational literature is 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. Python is also used in the raster graphics editor Gimp. It is used to create additional modules, filters, for example. Much of Civilization IV and Batterfield 2 are written in this language.
Python is used by companies such as Google, Facebook, Instagram, Dropbox, and Pinterest. It also works 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 reality, one might say, it begins with installation on a personal computer working environment. How to do it? It's simple: you need to follow the link of the official Python website, download and run the installer, and then carefully follow the steps it suggests.
Please note that you must download a file that is suitable for the operating system installed on your computer!
If the installation was successful, open the console (usually 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 “welcome message” 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 necessary. 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.
Launch IDLE. To create a tiny program, you only need to write one line of code.
print("Hello world!")
Enter this code into the IDLE window and press Enter. The environment will instantly respond with action - display the required text on the screen. The first program is ready.
Python is a widely used, high-level programming language that was named after the famous British comedy television show " Monty Python's Flying Circus" The Python language is simple in structure, yet incredibly flexible and powerful. Given that Python code is easy to read and without being too rigid in syntax, many consider it to be the best introductory programming language.
Python - description of the language given in Foundation describes Python:
Python is an interpreted, interactive, object-oriented programming language. It includes modules, exceptions, dynamic typing, high-level dynamic data types and classes. Python combines excellent performance with clear syntax. It provides interfaces to many system calls and libraries, as well as various window systems, and is extensible with C and C++. Python is used as an extension language for applications that require a programming interface. Finally, Python is a cross-platform language: it runs on many versions of Unix, Macs, and computers running MS-DOS, Windows, Windows NT, and OS/2.
Which programming language should you learn first?
You can start learning the Python programming language. To illustrate how Python differs from other introductory languages, think back to when you were a teenager.
Learning to program with Python is like driving your parents' minivan. Once you've driven it around a few times in a parking lot, you'll begin to understand how to handle the car.
Trying to learn programming using C ( or even assembler) it's like learning to drive by assembling your parents' minivan. You'll be stuck in a garage for years putting parts together, and by the time you have a full understanding of how the car works and are able to troubleshoot and predict future problems, you'll be burned out before you ever get behind the wheel.
Benefits of Python
Python is a universal language for beginners. You can automate workflows, create websites, and create desktop applications and games using Python. By the way, the demand for Python developers ( PostgreSQL, OOP, Flask, Django) has grown dramatically over the past few years in companies such as Instagram, Reddit, Tumblr, YouTube and Pinterest.
High-level general purpose language
Python is a high-level programming language. Using it, you can create almost any type software. This versatility keeps you interested as you develop programs and solutions that target your interests rather than getting stuck in the weeds of a language worrying about its syntax.
Interpreted language
The Python programming language for beginners is interpreted, which means you don't need to know how to compile code. Since there is no compilation step, productivity increases and time for editing, testing and debugging is greatly reduced. Just download the IDE ( IDE), write your code and click “Run” ( Run).
Code readability is key
Simple, easy to learn Python syntax emphasizes readability and sets a good programming style. With Python, you can express your concept in fewer lines of code. This language also forces you to think about program logic and algorithms. Because of this, it is often used as a scripting or integration language ( glue language) to link existing components together and write large volumes of easily readable and runnable code in short periods of time.
It's just fun
You can't name a programming language after Monty Python without having a sense of humor. Moreover, testing was carried out to compare the time required to write a simple script in different languages ( Python, Java, C, J, BASIC):
...Python requires less time, fewer lines of code, and fewer concepts to achieve your goal... And to top it all off, Python programming is fun! Having fun and frequent success builds confidence and interest in students, who become better prepared to continue learning Python.
Translation of the article “Why Learn Python? "was prepared by the friendly project team.
Good bad
The Python programming language is a general-purpose high-level language. It can be built in and extended. For example, it is included in some applications as a tool for writing macros. This feature makes the Python programming language a smart choice for many programming tasks. Where is the best place to use it? Python is perfect for projects that require rapid development. This programming language supports several paradigms. This is especially good for programs that require flexibility. Having multiple modules and packages saves time and provides versatility. The creator of the Python language is Guido van Rossum. At one time, the community awarded him the title of “magnanimous dictator for life.” Guido liked the features of several programming languages in the late 80s. However, none of these languages had the capabilities that he would like to have. So, for example, the language had to have the following capabilities:
- scripting language. A script is a program that is used to control other programs. Scripting languages can be used for prototyping and rapid development. For this reason, they are great at passing data from one component to another and freeing programmers from complex things like memory management. Programmers call Python a dynamic programming language.
— indentation for grouping statements. The Python programming language determines whether expressions belong to the same group using indentation. This group is called a code block. Other programming languages use different punctuation and syntax. So, for example, in C, the symbol "(" means the beginning of a sequence of commands. Indentation is a good practice in other programming languages. However, one of the first programming languages to enforce indentation is Python. What does this do? First of all Indentation makes the code easier to read. Code blocks require less marking of the beginning and end. This means there will be less punctuation marks in the code that can be easily missed. This all leads to a decrease in the number of errors in the code.
— high-level data types. Personal computers store data in zeros and ones. However, people need more complex forms of information storage, such as text. If a language supports complex data, it is said to support high-level data types. It is easy to operate with these types of data. In Python, for example, strings can be concatenated or split, converted to lower or upper case, searched, etc. High-level data types such as dictionaries and lists, which can store other data, have greater functionality.
- extensibility. Extensibility means that a programming language can be extended. Extensible programming languages are very powerful. Additions make them suitable for huge amount operating systems and applications. Extensions can add new data types, plugins and modules. There are several ways to expand in Python. Main group programmers are working to improve and change it. Hundreds of others write modules to serve specific purposes.
- interpretation. Interpreted languages are executed directly from source code that was written by humans. Programs written in compiled languages such as C++ must be translated into machine code. Typically, interpreted programming languages are slower because translation is not instantaneous. However, debugging and writing the programs themselves is noticeably faster, since there is no need to wait for the compiler to complete. Interpreted programming languages are easier to port to various platforms. It can be debated for a long time whether Python is a compiled or interpreted language. Although the programming language operates as an interpreted language in many respects, its code is compiled before execution. Many of its components run at full computer speed because they are written in C.
Guido started writing Python during his vacation in 1989. Over the next year, he refined the language, focusing on feedback from colleagues. The result appeared before the general public in 1991. That's when it was posted on one of the Usenet news groups.
Python for beginners
Before you can start writing programs in Python, you need to install it. There are significant differences between Python 3.5 and Python 2.7. Because of them, programs written in them are incompatible. This language is preinstalled on Macintosh computers. Its version will depend on the age of the operating system. If you're on Windows, you'll have to install Python on your computer yourself. You can select the installation package files directly on the Python.org website
Ways of interaction
One of the reasons for the simplicity that comes with programming in Python is that it comes complete with tools that can write, develop, and debug programs. Commands in interactive mode are entered one line at a time. This process is similar to how operating system accepts commands from the command line. You can also create short multi-line programs or import code from text files or Python modules. Beginners will probably find it useful to know that the interactive mode includes extensive help system. This method is very convenient for learning the capabilities of a programming language. The IDLE development environment includes tools for writing and running programs, and a name tracking system. This environment written in the Python programming language. It demonstrates the extensive capabilities of this language.
Interactive mode
In interactive mode you can do almost everything that you can do in the program. You can even write multi-line codes here. This mode can be used as a sandbox for safe experiments. Additionally, the interactive mode can act as an environment to learn Python programming. It can also be used as a tool for finding and fixing errors. It is worth considering that it is impossible to save information that was entered interactively. To do this, write a copy of the code and the result in separate file. You can use interactive mode as a calculator. Here you can also manipulate text or assign values to variables. It is also possible to import modules, functions or parts of programs for testing. All this makes it possible to experiment with Python objects without having to write long programs. There is also no need to debug programs by importing their parts one at a time.
Working interactively
After Python is launched, the terminal window will display information about the version of the program being used and its release date. There will also be several hints for further actions and an input prompt: >>>. To start working in interactive mode, you must enter an expression and command and press the enter button. Python should then interpret the command entered or respond appropriately if what was typed does not require a response. Here is a command that prints a line. Since the print location is not specified in the command, the information will be displayed on the screen.
>>> print “Hello World!”
It's hard to believe, but this single line is the program. Python interactively processes each line of code entered after the Enter key is pressed. The result will appear below.
Viewing information about an object
In interactive mode, there are two methods that can be used to view information about an object:
— enter the name of the object and press the enter key;
— enter the Print command, the name of the object and press Enter.
The result will depend on the object you select. When using certain types of data, these two methods can produce exactly the same result.
>>>x=
>>> print x
The result of typing the "print name" command will be slightly different from the result that was obtained for entering the name. The value in the first case is enclosed in quotes, but in the second it is not.
>>> x= "MySrting"
In cases where the name refers to an entire block of code, entering the name will provide information about the type of data, its name and storage location.
IN following example The command for creating a class named Message is given and information about it is displayed:
>>> class Message:
>>> Message
>>>print Message
Strings in Python
In the Python programming language, strings are sequences of characters. Create a string literal by enclosing characters in single, double, or triple quotes. The variable in the example above is assigned the value x.
>>>x= "My String"
Python string has several built-in capabilities. One such feature is the ability to return a copy of a string from lowercase letters. These capabilities are known as methods. To call a method on an object, you must use dot syntax. This means that after entering the name of the variable, which in this case is a reference to the string object, you must put the dot (.) operator. This is followed by the name of the method followed by an opening or closing parenthesis.
>>>x.lower()
Using the indexing operator s[i] you can get only part of the string. In this case, indexing will start from zero. S returns the first character in the string, s the second, and so on.
String methods can work with both regular codes and Unicode. They allow you to perform the following operations:
— changing the encoding (decode, encode);
— changing the register (lower, swapcase, upper, capitalize, title);
— counting (count);
— replacement and search (replace, find, rfind, rindex, index, translate);
— union and division (partition, join, split, rpartition, splitlines);
— checking the fulfillment of conditions (endswith, startwith, isalnum, isdigit, isalpha, isspace, istitle, isupper);
— formatting (ljust, center, rstring, strip, expandtabs, rjust).
Python: Working with Lists
While in the Python programming language strings are limited to characters, lists do not have any restrictions. Lists are ordered sequences of arbitrary objects, which may also contain other lists. It is also possible to delete, add or change their elements. The following are examples of performing these operations with lists:
>>> bases = [‘A’, ‘C’, ‘G’, ‘D’]
['A', 'C', 'G', 'D']
>>> bases.append('T')
>>> bases [‘A’, ‘C’, ‘G’, ‘D’, ‘T’]
>>> bases.reverse()
>>> bases [‘T’, ‘D’, ‘G’, ‘C’, ‘A’]
‘T’ >>>
>>> bases.remove('T')
>>> bases [‘D’, ‘G’, ‘C’, ‘A’]
>>> bases.sort()
['A', 'C', 'G', 'D']
In the example given, a list of symbols was created. After this, an element was added to one end of the list. The order of the elements was then reversed. Also, elements were retrieved by their index position. The element with value "T" was removed, after which the elements were sorted. The example command to remove an element from a list illustrates a situation in which the remove() method needs to be provided Additional information. In this case, it was the value that needed to be removed. Besides methods like remove(), the Python programming language also has another similar feature called a function. The main difference between a method and a function is that a function is not associated with any specific object.
Functions in the Python programming language
In a programming language Python functions are used to perform actions on one or more values. After that they return the result. Python has a large number of built-in functions. Let's look at some examples of built-in functions:
— len() – returns the number of elements in the sequence;
- list () - returns new list, which is initialized from some other sequence;
- dir() - Returns a list of strings that represent the attributes of an object.
Python also allows you to define your own functions.