Computer and Program • A computer is an electronic machine that is used to store, retrieve, and process data under the control of set of instructions called program. • The set of instructions to the computer hardware is called program or software. • There are many programming languages invented to write programs. For example: Python, Java, C, C++, HTML, CSS etc. @pearahmedbhuiyan What is Python? • Python is a programming language in order to write a program. • It was written by Guido van Rossum and released in 1991. • The latest version of Python is Python 3.8.3 • Python works on different platforms such as Windows, Mac, Linux, Raspberry Pi, etc. @pearahmedbhuiyan What can Python do? • Python is a programming language used to write a computer program (software). • It can be used for but not limited to the following: – Connecting to database to use data in a program. – Reading from, writing to and modifying an external file. – Handling huge data and complex mathematical computations. – Writing server side programming in web applications (software). @pearahmedbhuiyan Python Syntax compared to Other Languages • Like human language computer programming language follows certain grammar (rules) which is called Syntax. • Python has a simple syntax somewhat similar to English language with some influence from mathematics. • Python has syntax that allows programmers or developers to write programs with fewer lines than some other programming languages. • Python runs on an interpreter which means that code can be executed as soon as it is written. @pearahmedbhuiyan Python Syntax compared to Other Languages • Python uses new lines to complete a command or single statement whereas other programming languages often use semicolons. • Python relies on indentation, using whitespace, to define a block of statements. Other programming languages often use curly- brackets for this purpose. @pearahmedbhuiyan Python Installation • Many PCs and Macs will have python already installed. • To check whether python has already been installed on a Windows PC: -search in the start bar for Python or run the following command on the Command Line (cmd.exe): C:\users\your computer name>python --version • To check on Mac PC open the terminal and run: python --version • On Linux open the command line and run: python --version @pearahmedbhuiyan Integrated Development Environment (IDE) • An Integrated Development Environment (IDE) is a software that provides with good environment to develop a software. • Software developers use different tools throughout the development of a software like text editors, code libraries, compilers and test platforms. • An IDE provides with many of these tools together as a single framework , a suite or service. • An IDE simplifies software development and minimize coding mistakes and typos. • Most popular IDE tools include Eclipse, NetBeans, Microsoft’s Visual Studio etc. @pearahmedbhuiyan Integrated Development Environment (IDE) • You can write Python program in a Text Editor or in an Integrated Development Environment, such as Thonny, Pycharm, Netbeans or Eclipse. • In the class you will be writing Python programs on an online IDE named Repl.it whose web address is https://repl.it • On the web browser address bar enter the address https://repl.it press enter or search by writing repl.it and click the link of repl.it. The Repl.it will open. @pearahmedbhuiyan Repl.it @pearahmedbhuiyan Repl.it @pearahmedbhuiyan Repl.it • You can click <start coding> and choose the programming language Python to start writing a program in Python. • There is a sign in option before clicking <start coding>. You need to sign up in order to sign in. • Sign up once and sign in to keep your program files for using next time. @pearahmedbhuiyan Choose (click) Python After Signing In Repl.it @pearahmedbhuiyan After Choosing (Clicking) Python @pearahmedbhuiyan Repl.it Window • There are three rectangular areas in the repl.it window. – The middle one is to write the program. – The right one is to see the output of the program when it is run. – The left one for different tasks such as exploring files, adding files and folders, uploading files etc. There is a Run button above the rectangular areas that you click to run the program. @pearahmedbhuiyan First Python Program @pearahmedbhuiyan Print() Function • The print() function prints the specified message to the screen or other standard output device. • The message can be a string or any other object which is converted into a string before written to the screen. • The message is written inside the parenthesis of the print() function. @pearahmedbhuiyan Printing a string using double quotes @pearahmedbhuiyan Printing a string using single quotes @pearahmedbhuiyan Escape Characters • Use an escape character to insert a character that is illegal in a string. • An escape character is a backslash \ followed by the character you want to insert. • String with single or double quote can not be enclosed inside the same quote. It can be done with escape sequence character. For example: “This is \“Orchid\” flower”. Here \” is called escape sequence character. @pearahmedbhuiyan Using Escape Sequence @pearahmedbhuiyan Some Escape Characters Code Result \’ ‘ \” ” \\ \ \n Moves to new line \t Keeps space of tab @pearahmedbhuiyan In Class Exercise Read the handout and then write the answers of the following questions in your own words. 1. What is Python? 2. What can Python do? @pearahmedbhuiyan In Class Exercise Open the repl.it IDE on your browser and write the following programs: 3. Write print() commands to print five lines of text describing about Python and show the output. 4. Write a program to print the following: I like Programming. There are many programming languages such as Python, Java, C, C++ etc. The syntax of Python is simpler than other programming languages. @pearahmedbhuiyan In Class Exercise 5. Write a program to output (display) at least five lines about IDE to the screen. 6. Write a program that will print text (string) describing five advantages of Python compared to other programming languages. 7. Write a program to display the following: I like fruits specially Apple, Orange and Cherry. I am going to buy some fruits tomorrow. I am not sure which store I should go. Do you have any suggestions. @pearahmedbhuiyan In Class Exercise 8. Write a python program to print the following: I like ice cream. How do you like a “Toyota” car? Do you like ‘Python’ programming? My favorite fruits are: ‘Mango’, ‘Banana’ and ‘Pine Apple’. Student ID Name Mark 101 James 90 @pearahmedbhuiyan Homework 1. Write in your own words at least three characteristics of Python Syntax compared to other programming languages 2. Write a program that describes about Python by printing at least seven lines of text. 3. Write a program that will display text describing the syntax of Python. 4. Write a program that will output text describing about repl.it. Homework 5. Write a program with comments to display the following: I like shopping. Today I am going to buy some fruits specially “Orange”, “Guava” and “Strawberry”. Tomorrow I am going to ‘Bayview village’. ID First Name Last Name 101 John Edward.