History of Python and Its Importance Python is a general-purpose programming language that was named after Monty Python. It is simple and incredibly readable since it closely resembles the English language. But still, why should you use Python? Python is a language that finds use in nearly every domain possible. Its official website will give you an overview of this. In addition, its simplicity and the way it ensures tasks can be performed using fewer lines of code are encouraging many developers across the world to take it up. Play Video 4803892 Currently, there are two common versions of Python: Version 2 and 3 and later. Apart from some syntactical differences, they are pretty similar. As support for version 2 would fade over time, our course supports version 3. It is preferred to uninstall Python 2 before installing Python 3. In case one does not want to uninstall Python 2, to avoid confusion, setup virtual python environments using pip on the prompt: sudo apt install python-pip. Play Video 4803892 A high level language called a source code is used to write a computer program. Source codes have to be converted into machine language with the help of compilers and interpreters. Compiler vs Interpreter To install Python 3 on your own system, follow the steps in the document provided at the end of the next segment. You will need various Python packages (or synonymously, libraries) for specific purposes. Anaconda is an open-source distribution that simplifies package management and deployment. The package management system 'Conda' manages package versions. We strongly recommend using Anaconda to install Python as well as the packages since it comes preloaded with most of the packages you will need. Advantages of using Anaconda 1. It is easy to manage and supports most of the libraries required for Machine learning/Artificial Intelligence problems. 2. Anaconda comes with many libraries such as NumPy, OpenCV, SciPy, PyQt, the Spyder IDE, etc. Anaconda can be downloaded from anaconda.org and can be installed like any other normal software. There is no need to download Python separately; the Anaconda installer will do this for you. Make sure you select Python 3.x while downloading Anaconda. Note for experienced Python programmers: In case you're already using Python along with an existing package manager such as pip or easy_install, you can continue to do so. However, make sure you're using Python 3.x. Jupyter Notebook You’ll use the Jupyter IPython Notebook as the main environment for writing Python code throughout this program. The key advantage of using Jupyter Notebook is that you can write both code and normal text (using the Markdown format in Jupyter) in the notebooks. These notebooks are easy to read and share, and can even be used to present your work to others. Here’s a brief overview of Jupyter Notebook. The document given below provides instructions for installing Python and the Jupyter Notebook using Anaconda. Installation_documentation Download Also, refer to the document for help with installing Anaconda successfully. It is important to note that you need to install Python 3.x (the latest 3.x version available), not 2.x. Please proceed to the next segment only after installing Anaconda and the Jupyter notebook. Additional Reading If you want to know about the Jupyter notebook in brief check out this link: Jupyter Notebook quick starter guide Writing Your First Program in Python You can download the Python notebooks used in the lecture from the link below. It is recommended that you keep executing the commands on your computer at pace with the lecture on your jupyter notebook. Also, from the coding perspective for practice questions and out of video questions, you are expected to use jupyter notebook. Jupyter notebook is an interactive computational environment in which one can combine code execution, rich text, mathematics, plots and rich media. Python notebook Download Now that you have installed Python notebook on your computer, let us start our journey in Python by writing a small code and see how it executes. Play Video 4803892 You have come across certain shortcuts involved in the execution of the demo code. But there are other shortcuts that may come in handy as well while using the Jupyter notebook. For these shortcuts, you can download and explore the notebook given below. It provides a brief description of different shortcuts, and you will gain expertise by using them regularly during hands-on practice. Jupyter Notebook Introduction Download Note: Some of the questions here may include concepts from the shared notebook. Question 5/5 Mandatory Question 1Correct Question 2Incorrect Question 3Correct Question 4Correct Question 5Correct Additional Reading If you want to know about the shortcuts for mac users and magic commands existing in jupyter notebook, the links are provided below: Jupyter mac shortcuts Jupyter magic commands In the next segment, we will learn about the different data types present in python and how to convert one data type into another with the help of type casting. Data Types in Python Now that you know how to use Jupyter notebooks and have learned how to write the basic “hello world!” program in Python, it’s time to understand how to declare a variable in Python. We will also learn about the different data types available in Python. The following video will offer you an introduction to the basic syntax of declaring a variable in Python. Play Video 4803892 You have learned that variables are nothing but a memory location to store values assigned to them. Some of the properties of these variables are: 1. There is no need to declare the data type of the variable as done in other programming languages, such as C, C++, and JAVA int c = 5 string name = 'Rahul' 2. The variable name (or identifier) cannot start with a number, i.e., declaring something like 2name = 7 throws an error. 3. Python is case sensitive or in other words, these variables are case sensitive. This means that declaring name= 2 & Name = 4 would create two different variables. Play Video 4803892 Let us look into the concept of converting one datatype to another in the following video. Play Video 4803892 In the previous video, you learned about the various data types supported in Python. Now, let us move on and see how you can change one data type to another in Python called typecasting from the video given below. In order to change the data type of a particular variable, you can simply call the following inbuilt methods in python. In the above snapshot of code, you are assigning a value to a variable (x) and then using typecasting, converting it into different data types. So for example, when you convert x into an integer it converts the floating-point value into an integer value. Based on your learning about various data types and typecasting in Python from the previous videos, attempt the quiz given below. Question 2/2 Mandatory Question 1Correct Question 2Correct In the next segment we will learn about the various arithmetic operations performed in python programming and most importantly the precedence that we follow for these operations. Arithmetic Operations In the previous segment, you learned about various data types in Python. Arithmetic operations are an integral part of every programming language. Let's understand how you perform one in Python from the following video. Play Video 4803892 To do some mathematical operation which involves one or more than one operator, we did follow some rules. The same is the case in Python where if multiple operations have to be done in a single problem, then we make use of operator precedence rule. Let us understand Operator precedence using an example. a = 4+(8**2)-3**2%1 To find the value of the variable 'a', the following steps have to be followed. Step 1: The first step is to deal with brackets as it holds the highest precedence among all operators in the given expression. The expression inside these brackets [(8**2)] will get executed first to return 64. Updated Expression: 4+64-3**2%1 Step 2: Moving on, you deal with the exponentiation operator [3**2] as it has the next highest precedence when compared to other operators in the expression. Updated Expression: 4+64-9%1 Step 3: Now you deal with the remainder operator as it has higher precedence over subtraction and addition. This means the value 9%1 gets evaluated to return 0. Updated Expression: 4+64-0 Step 4: In the next step, the subtraction operator gets executed as it holds higher precedence over addition. Updated Expression: 4+64 Step 5: The final step would be to perform addition Answer: 68 Operator Precedence (from highest to lowest) : Preference Operator Type (respectively) 1 ** Exponential 2 ~, +, - Complement, Unary plus & minus 3 /, *, %, // 4 +,- Add, Subtract 5 >>, << Bitwise shift right & left 6 & Bitwise AND 7 ^, | Bitwise or regular OR 8 <, =, <, >, >, = Comparisons 9 <, >, ==, != Equality 10 =, %=, /=, //=, -=, +=, *=, **= Division, Multiplication, Modulus, Floor Division Assignment 11 is, is not Identity 12 in, not in Membership 13 not, or, and Logical And this is how operator precedence rule plays an important part while doing arithmetic operations in Python. Based on the concept you learned through the given above example and video attempt the quiz given below. Question 1/2 Mandatory Operator Precedence What would be the output of the following code? x=3 y=2.5 z=5 print(X+y/z) 5.5 1.1 3.5 Error Attempt 0 of 1 Submit In the next segment we will learn about the various string operations performed and methods associated with it in python programming. String Operations In the next set of videos, you will learn about various operations and manipulations done by a string. So, let's have a look at each one of them. String Indexing Play Video 4803892 In the previous video, you learned about Indexing in strings. Always remember that forward indexing starts with 0 and reverse indexing starts with -1, strings are immutable which means they cannot be changed once created and strings can be modified by slicing a part of it and concatenating. String Concatenation Play Video 4803892 Now, let's move on to the next video and understand another important concept string slicing. String Slicing Play Video 4803892 Question 1/2 Mandatory String Slicing How will you extract Python from the string word "I love Python programming"? (More than one answers may be correct.) word[7:13] word[7:12] word[-12:-18] word[-18:-12] Attempt 0 of 2 Submit In the previous videos, you saw how to do indexing and slicing in strings. But let us say you want to change the character case or count the number of occurrences of a substring in a string, they can be performed using the inbuilt string methods. In our next video, let's look at these methods in detail. String Methods Play Video 4803892 Some more string methods: 1. str.len() , str.find() , str.format() 2. str.replace() , str.join() , str.split() 3. str.upper() , str.lower() 4. String boolean methods : str.isalnum() , str.isalpha() , str.isnumeric() , str.isspace() , str.islower() , str.isupper() , str.istitle() In the previous video, you saw slicing in a string through several examples. Now, based on your learning attempt the quiz given below.
