_3 Python Tutorial for Beginners _ Getting Started with Python

Episode Transcript

Speaker 1 (00:04):
Welcome back Aliens, my name is Dhavan Reddy and let's
continue with this series of Python. Now, we have talked
about what is Python and we have talked about how
to install Python on your machine. It's time to start
with the actual stuff, right? And we are waiting for this. Now,
the step one would be, of course, you need to
open your IDE. Now, if you remember, in the installation,
we have installed two softwares. One is the interpreter and

(00:26):
second is your PyCharm. But will not be using PyCharm
in this tutorial. We'll start with the basics so that
you will be having that hands on experience on IDLE
as well. So let's try it out. So what I
will do is I will open my IDLE and in that.
So this is your prompt. OK, so this is your prompt.
This is where you will type your code now. Before

(00:48):
going for the actual code, we have a question here.
Why do we code and why do we write a code?
Now think about this. We are living in a world
where everything is done with the help of computers, right? Example,
if you want to send an SMS, if you want
to send an email, you don't have to do that.
Your computer will do it for you if you instruct it.
example nowadays we have this amazing thing you know we

(01:08):
have Siri on iPhone and then we have Google Assistant
on Android phones you know you can ask them to
do things for you example you want to set an
alarm you can you know they will do it for
you but then how they understand what you want to
say so you need to talk to a computer and
if you want to talk to your computer you need
to understand their language right and the language which computer

(01:29):
understands is binary code which is zeros and ones Now
that means if you want to talk to computer you
need to talk to them in terms of zeros and ones.
Now it is not actually possible right of course. So
what you have to do is you need to use
a language which both will understand. So we all know
English language but computer will not understand plain English right

(01:51):
because we have some grammatical stuff here. so what we
have done is we have created programming languages now those
are not actually example we have high level languages now
those are not exactly a binary code and they are
not even exactly same as english they are somewhat you
know they have their own protocols they have their own

(02:11):
grammar which we use so when i say english so
we have level one english then we have level two
which is programming language and then we have level three
which is your which is your binary format So you
understand English. So what you will do is you will
learn a programming language, let's say Python in this case,
and then you will write a Python code which will
get converted into binary format, which a computer will understand.

(02:32):
So if you say, hey, computer, do something for me.
So let's go with a very simple stuff here. Let's
say I want to add two numbers. So you will say, hey, computer,
two plus three, a computer will say, OK, five. But
then how do you talk to a computer in this case?
So we are using Python and then we have an interpreter.
In fact, in Python, as we discussed, it's one of
the easiest language, right? So what I will do is
I will say two plus three. This is the simplest

(02:54):
task you can do on Python. So I will say
2 plus 3. It works. You can see we got 5. Yes,
this is working. What else? What about subtraction? You know,
we love mathematics, right? So let's apply all the arithmetic
operations here. Let's try 9 minus 8. It should be 1, right?
We got 1. So yes, subtraction also works. Okay, what
else we can use? Can we use multiplication? Let's try

(03:15):
4 into 6. It should be 24. Yeah, that's right.
We got the answer. So yes, addition, subtraction, multiplication works.
What about division? Okay, let's try. So when I say division,
it should be 8 divided by 4. And I'm expecting
the answer to be 2. Yeah, it's 2. But hold on.
There is a difference here. You can see when we
say 2 plus 3, we got 5. 9 minus 8,

(03:36):
which is 1. So... When you subtract two numbers, we
are getting that number, right? And specifically, these are integer numbers, right?
We all use integers. But then when you divide a number,
it is giving you a point value. Now, this point
value is also called as float numbers. So, we have
integers and then we have float. Now, float stands for
floating point representation. Okay. But why it is 2.0? Because

(04:01):
when you divide numbers, you might get point values. For example,
when you say 5 divided by 2, you will get 2.5. Example,
let's try it out. So if I say 5 divided
by 2, you got 2.5 and you want that 0.5 value, right?
That's why it converts your number or your output into
a float value because they want to give you the
exact value. But what if you don't want it? What

(04:23):
if you want only the quotient part? Example, when I
say 5 divided by 2, you want only 2. You
don't want 0.5 value. So we can do that. You know,
if you want only integer output, so we don't want
float now, we want only integer, you can do that.
You can say 5. Instead of giving 1 slash, you
have to give 2 slash. Now, this is also called
as integer division or it is also called as flow division. So,

(04:45):
when I say run this code, you got 2. So,
this is working, yeah. Okay, what else we can do here?
Can I do, you know, combination of this arithmetic operation? Example,
let's say 8 plus 9. Yeah, and then subtract it by,
let's say 10. Is it possible? Let's try it. So
it works, you know, so you can have multiple operations, right?
But then we have to follow grammar, right? If you

(05:06):
say 8 plus 9 and then subtract, you forgot to
type 10 there. It will give you an error, which
is invalid syntax. And that's why you need to follow
the grammar as well. So when you learn a language,
you need to follow grammars in the same way. In
programming as well, you have to follow grammar. Can I
use those brackets stuff which we used to use in mathematics? Yes,
we can. For example, let's say we have 8 and

(05:29):
then I'm adding that value. But then I also have
a value which is 2 into 3. Now, which one
will be done first? Of course, the multiplication part, right?
But then what if you want to do it? Oh,
let's try this first. So you can see we got 14,
which is 8 plus 6. But what if I want
to say 8 plus 2, which is 10 and then 3.
So in that case, you need to use brackets, right?
If you remember the board mass rule, so I would

(05:51):
say 8 plus 2, which is in the brackets and
then into 3. So you can see we got 30.
So yes, this also works. So when you multiply, so
if you give a bracket, it will be solved first. Okay,
this is cool, right? Now what else we can do here?
What if I want to find a power of or
we can say exponent, you know, so let's say if
you have 2 raise to 3 or 5 raise to 6.
How can I do that? So I will say 2.

(06:12):
I want to find cube of 2. So in that case,
I can say 2 into 2 into 2. We can
do that. But then what if you have 2 raise
to 10? You cannot simply type 2 into 2 into
2 into 10 times. Because this will give the right answer.
It is 8. Otherwise, you can say 2. You can
give double star and 3. So double star or double
hashtag symbol simply means power off. So when you say

(06:34):
2 raise to 3, so this is 2, hashtag, hashtag, 3.
And you can see we got 8. so that's how
you have to find you have to do this all
this operation so now we know how to add two
numbers how to subtract two numbers and then multiplication division
a flow division but what else we can do here
in fact you know we can we can also do
modulus now what is modulus here let's say i'm dividing

(06:55):
i'm dividing two numbers which is 10 uh divide by
2 or maybe 3 in this case Now it's a
10 divided by 3. It will give you 3, right?
But then we also have a remainder here, which is 1.
So when I say 10 divided by, which is the
integer division, you've got 3. That's right. But what if
I want the remainder part of it? So I would
say 10. And we have to use a special symbol here,

(07:16):
which is modulus. And we'll say 3. You can see
we got 1, which is a remainder. So when you
say 10 mod 3, you will get a remainder, which
is 1. Okay, this works. Yay! Now, you know all
the operators, right? Now what else we can do here?
Now till this point, we have discussed about two types.
One is the integer type, which we have done here.

(07:37):
And then we have talked about float. What other types
we can have here? Can we have string? You know
what a string means? It's a combination of characters. Example,
my name, Naveen, is a string. Python is a string.
Camera is a string. YouTube is a string, right? So
we have to use, can we use string here? We can.
Let's try. So what I will do is, whenever you
want to use string, you should always use single quote

(07:59):
or double quote. So let's try. So I will use
my name first. So I will say single quote and Naveen.
So we have to use a quote here. So you
have to say Naveen. And enter, you can see we
got the same value. We got Naveen. Now there's another
way of printing these values. You can also print by
providing some functions. Oh, that's a new word now. Note
of functions in Python language. We have certain functions which

(08:20):
we can use and one of the function is print.
Now what print means or what function means is it
is a set of tasks which you will be doing.
For example, in print, which is inbuilt, it has certain
tasks which it will do. You just need to call it.
Can we define our own functions? Yes, we can. So
print is an inbuilt function. We can define our own

(08:42):
functions as well. So you can do all these operations
in one function. You can do that. But we'll see
that later. How do we define our own function? But
time being, let's use print. And when you have a print,
you normally give this round back edge to pass any parameter.
Let's say if you want to pass something to the function,
you can do it here. In this case, I want
to pass my own name. So I'm saying print Navin.

(09:03):
So you can see it works. We got Naveen as
a value there. Okay, that works. Now, if you see
the difference between Naveen, the earlier command here, if you
compare this one with this one, see the output. So
in the earlier one, the single code is getting printed
as well. But in the second one, it is only
printing my name. And that looks beautiful, you know. Okay,
let's try to print something else. I will say print.

(09:24):
And here I want to print, let's say, Naveen's laptop.
So Naveen's laptop. It should print Naveen's laptop, right? When
I say enter, oh, we got an error. that's weird
now what went wrong here now if you observe here
we have single code as a starting one and then
we also have a single code here so that means
that is one string and then this thing which is

(09:44):
s laptop it is not as a part of that
single code that's where that's where the problem starts so
you cannot simply have single code anywhere right so how
do you solve this problem to solve this problem we
have two solutions the first one is you instead of
using single code you use double quotes. Example, you can
say print and in double quotes, you can say Naveen's laptop. Now,

(10:06):
since the starting and ending is done with the help
of double quotes, you don't have to worry about the
single quote in between. And if I say enter and
you can see we got the output as Naveen's laptop.
Now what else what are the commands we can do
so this this thing works here I will have to
think about this what if I want to print double
quotes in a statement let's say we have print inside
double quotes I am saying Navin laptop but I want

(10:29):
to print laptop in double quotes can I do that
example the output should be Navin and laptop but then
the laptop should be in double quotes we cannot do
that because you know the first double quotes and second
double quotes will be getting ended here so this this
is my first string What about this laptop? Now, in
that case, we will be using single code. So single
code and end with single code. So you have to

(10:51):
make sure the string part should be different from the
part which are inside. So if inside we have double quotes,
then outside we should be using single code. Right. That
makes sense. Right. So you can see we got the output.
But here's a trick. What if I have both in
the string? Example, let's say we have print. I want
to say Naveen's laptop. And you can see we have

(11:13):
both now. We have double quotes and we have single
quote both. That's where the problem starts. So what you
will do now, because if I say enter, you got
invalid syntax. In that case, we will say single quote
navines and then in double quotes, we'll say laptop. The
issue is with this S, right? This S is coming
before a single quote. So we have to tell your Python, hey, Python,

(11:33):
can you just skip that special meaning of that single quote?
And the way you do that is by giving a slash.
So when you say backslash, it will make sure that
you it will ignore the special meaning of that single code.
So when I say enter, it works, you know. So
these are the basic fundamentals which we're talking about. Now
let's do some fun here. So again, we'll continue with
the print later, but we have some fun thing here.

(11:54):
What if you want to print Navin two times or
you want to print Navin three times? Can I do that?
Of course, we can write. You can type Naveen and
then Naveen again. Or you can also use a plus
character here. So if you want to concatenate two strings,
so we have two strings here, right? We have Naveen
and we have Naveen. So when I say enter, so
you can see we have Naveen and Naveen. So we
are combining it. What if I want to print Naveen

(12:16):
three times or 10 times? In that case, you know,
you can play with the numbers as well. So you
can say 10 into in single code. You can say
Naveen and say enter. You can see we got Naveen
10 times. Yeah. So Python is fun, actually, you know,
you can you can play with it. You can do
some experiment. That's amazing. What if I want to print
this one? You tell me. OK, you try to guess it.

(12:36):
Will it work or not? Just pause the video, guess it.
Let me know in the comment section if it will
work or not. And then we can continue. What I
will do is I will print something. I would say
C colon slash. I have a direct because docs slash Naveen.
So pause the video, think about it and let's see
what output you are giving. Let's try. Answer enter. Oh,

(12:57):
this is weird. We were expecting it will print C
colon docs slash Naveen. But unfortunately it is giving a
new line and then Avin. What's wrong? Now, slash n
has a special meaning in Python. What is that special meaning?
And the meaning is it means new line. So slash
n means new line. And that's what is happening here.

(13:19):
It prints. It is printing C colon slash docs. And
then it comes to a new line because of slash n.
It is saying a win. OK, what I do is
I want to print it. I want to print it
as it is. How do I do that? It's very simple.
You just need to cancel the special meaning of that thing. Right.
So you want to print this string as it is,
which is also called a raw string. So I want

(13:40):
to print this one as a raw string. In that case,
you just specify R before the thing and you will
say C colon slash docs. slash Naveen. So we are
printing this stuff as it is. So when you say R,
it means raw string. Don't try to convert it. That's
what you are saying to Python. Hey, don't just try to,
don't try to convert that slash into a new special
character and say enter. It works. Yeah. So everything is

(14:03):
looking good now. So I hope you enjoyed this stuff,
which we are doing here, playing with this stuff. So
in this, in this video, we have only talked about
how can we use certain operators and then playing with printf.
In the next video, we're going to talk about how
to use variables. Now, if you are enjoying this series,
let me know in the comment section about your thoughts.
And if you have any questions, you can put that
as well. I do read your comments, by the way,

(14:26):
so that I can answer that in the next video.
And if you are liking my videos, click on the
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Thank you so much, everyone. Bye-bye.