Sunday, 28 May 2017

Beginners Python Programming Tutorial - How to become a Python Jedi - Part 5 : If-Else statement


Welcome back friends to another post on TheCodingProject and we are back with the fourth chapter of the Beginner Python programming tutorial - How to become a python Jedi. This time we are going to learn about decision making in python using the If-Else statement.

The If-Else statement?
In Python Programming, decision making is done by using a conditional statement like the If-Else statement. An If statement consists of 3 parts →
  • If keyword
  • a conditional operator
  • the values which needs comparison

Now it should be kept in mind that the only values that an If condition returns are a True or a False , Using this True or a False we can decide if the condition that we are trying check is right or wrong.
When Coding knowledge came to my rescue→
Let me tell you a story about how coding knowledge came to rescue . I have this neighbour named Alex who doesn't quite seem to be a regular guy. Wait ! actually he never seemed to me as a regular human 😟. This one day I was visiting him at his home for some work when I noticed something unusual. His living room is decorated with his family photographs, he has the photographs of his entire family tree over there starting from his great grandfather down to him. The weird thing that I noticed was that all the men in these photographs looked similar to him as if he himself was present throughout his family history. Is Alex a Vampire ? 😓 With this frightening thought in mind I ran back to my house and jumped straight to the computer and started to code. Using my superhuman brain I made a python program which would hack into his personal computer and collect all his personal information and then the program would calculate his age & use that knowledge to decide if Alex was really a Vampire. Now, that program is highly confidential so I won’t show you my entire code but as you guys are so much interested I will show you the snippet that is really pivotal in deciding Alex’s truth →





Copy & paste the above code in your editor and run this code. In the above code we have an If condition & an else condition. Let’s assume we have the age as 100. Now when the above code runs the code touches the If condition & checks if age is greater than or equal to 0 or age is less than or equal to 99. Notice that we have used an or operator so the condition becomes True even if only one of the condition matches & as age is 100 ( greater than 0) so the If condition returns a True & the control enters the If statement to print the statement inside the print method.

Let’s modify our If-Else statement to make it more robust. Copy and paste the below code in your editor and give it a spin→







As you can see this time we have an and operator instead of an or. So this time our If condition will return True  only when age is greater than or equal to 0 and less than or equal to 99. Now as we have the value of age out of the bounds of 0 to 99 so the control skips the If condition & jumps to the line of code immediately after that which is the Elif  statement. This kind of expression is known as a  Nested if-else statement, wherein we have another If condition immediately after the first If condition to put a second conditional check and in python programming language it’s written as Elif. In our case the control checks that age is not satisfying even the condition inside the nested If statement so it skips that too and jumps to the next condition i.e the Else  statement and as there are no further condition defined for this else statement, so it returns a True & the statement inside the print method is printed.


Conclusion→
You can define n number of rules using the nested if-else conditional statements. Go ahead & try to extend on the above example code by implementing your own rules with nested if-else statements. The code examples can be found in the Python Decision Making.py file in my Github repo.

So, folks this was all for this week but we shall return with another chapter of this tutorial with some new concepts to learn.

Subscribe to my youtube channel to watch the coding in this tutorial in action.

If you have any questions, suggestions or comments you can post your comment here or you can also bug me on Quora, Twitter or on Facebook.

Sunday, 21 May 2017

Beginner Python Programming Tutorial - How to become a Python Jedi - Part 4 - Comparison Operators



Welcome back friends to another post on TheCodingProject and we are back with the fourth chapter of the Python programming tutorial - How to become a python Jedi. This time we are going to learn about comparison operators.

What are Comparison Operators ?
Comparison operators are used to compare any two values, be it two numbers , two strings or any other objects. In short these operators help us to make a decision by giving back the results of a comparison. Comparison operators always return either a True or a False.

Different Comparison opearators →
== Equal to
!=  Not equal to
<   Less than
>   greater than
<= Less than or equal to
>= Greater than or equal to

Examples of Comparison operators →
Let’s get into some examples to better understand the usage of comparison operators. Copy the below code and paste it in pycharm or any other editor that you have. Additionally you can also download the comparison operators.py code file of this tutorial from github. →










For the first print statement the Equals to operator denotes that we want to compare that whether the integers 1 & 2 are equal to each other or not. When the control finds that both the integer values are not equal then it returns a False. Similarly for the second print statement when control finds that the two strings are not equal to each other so it returns a False once again. But in the third print statement we are comparing to see if 45 is greater than 34 and since it’s true, so a value True is returned. Similarly in the last print statement since 56 is equal to 56, so the condition less than or equal to evaluates to True.  
So, folks this was all for this week but we shall return with another chapter of this tutorial with some new concepts to learn.

Subscribe to my youtube channel to watch the coding in this tutorial in action.

If you have any questions, suggestions or comments you can post your comment here or you can also bug me on Quora, Twitter or on Facebook.


Monday, 1 May 2017

How to become a Python Jedi - A Python programming tutorial - part 3(Boolean operators)




Welcome back friends to another episode of TheCodingProject and we are back with the third chapter of the Python programming tutorial - How to become a python Jedi. This time we are going to get a taste of boolean operators.



What are Boolean Operators ?
Computers don’t understand the common human language, they only speak and understand machine level language and this language is made up of only two numbers 0 & 1. These numbers are known as binary numbers & this language is known as binary language. Now if you are a crazy nerd like me and you wanna know more then dive in here. The numbers 0 & 1 also represent decision making as they also represent True (for 0) & False (for 1) and these two operators are known as boolean operators.


Enough talk man, I’m here to learn code!!😠
Okay Okay I just took a trip in my emotion boat. I know you want to learn code so let’s just cut the talk talk & dive to code code. Yayyy!!
Boolean operators in action
Copy the below code and paste it in pycharm and any other editor that you have code →



What the above code gives us ? We remember from above section about boolean operators that they represent True (for 0) & False (for 1) and in the above example for the first print statement when we try to compare OS1 with OS2 the python interpreter checks that IOS(OS1) is not equal to Android(OS2) so the interpreter returns a False. In the second print statement we are checking if ‘IOS’ is not equal to ‘Android’ which resolves to true and that’s why the second print statement returns True.
We shall now look into some more examples. Copy and paste the below code in your editor and run the code →




Let’s say you and me are to arrange a party tonight and we list down what we need for the party but we have a difference of opinion and to come to a conclusion we turn to the geeky method of decision making and that’s through python. We list down our choices in the following variables → my choices are listed in drinks and food, your choices are listed in for_party. Now, we check that is your choice similar to my choice? The first print statement gives us a False because the values mojito is not equal to the either drinks or food. You have noticed that we have used the boolean operator or in the first statement which tells the interpreter to check if the value of variable drinks or value of variable food is equal to the value of variable for_party. Run the second print statement as well and analyse why we get a True over there. Here’s a hint for you → Notice the is not statement.


To summarize what we have learned through the above examples just go through the below table, it is a kind of cheat sheet during the usage of boolean operators →
Operators
Results
True and True
True
True and False
False
False and True
False
True or True
True
True or False
True
False or True
False


So, folks this was all for this week but we shall return with another part of this tutorial with some new concepts to learn.

Get the code files for this tutorial in Github.


Subscribe to my YouTube channel to watch new python programming tips and tutorials.


If you have any questions, suggestions or comments you can post your comment here or you can also bug me on Quora, Twitter or on Facebook.