Basic Python Syntax: Comments, Print Function, and Case Sensitivity

hi guys welcome back to mastering python today we're going to start looking at some basic python syntax we're going to

look at commenting indenting case sensitivity how to use the print function properly and where to get help

when things don't quite go to plan before we get started just a little word of caution it can appear that the first

lessons in this course are a little bit dry and that's okay we're we're really covering fundamentals we're making sure

that you have a strong Foundation to move on to the more intermediate an advanced topic so don't be discouraged

stick with it look at variables look at the syntax take it all in make sure that you grasp these Concepts yeah it's okay

if it's a little bit dry we'll get to loops and conditionals when stuff becomes Dynamic very very soon all right

that out of the way let's jump into vs code so you remember VSS code from last time um you created a file you wrote

your hello world program why don't you do that again just to make sure that you still remember how to do these things so

first things first create a new file called hello.py and then write the hello well

program and execute it pause the video and when you're done check back with me right how did you get on hopefully you

remembered everything so first of all to create a new file we either select this new file button here or we can right

click and go new file and we call this file hello.py remember that python files end

in py and vs code is very smart that it already puts the python icon here to tell you that it's a python file now the

the hello world program is very very straightforward it's print and then parentheses hello comma world

exclamation mark now to run this you had to open a terminal and there were several ways to open it you could go to

view terminal or use the shortcut here and this will open the terminal window at the bottom and all you had to do here

is run python we called it hello py press enter and there we go so we have our hello world written out here

what happens if we want to add a bit more complexity we want to say more than just hello world we can just add another

line where we go learning python is fun yay something very very simple so let's try it out python hello py in the

terminal you can just press the up and down arrows and this will cycle through your previous

commands there we go and we have it we have hello world and pyth learning python is fun yay so you can see it goes

one command by command and this can be very complex we can say um it's a nice day to

Learn Python when we run the command there we go we now have all three lines printed

out now the print command is going to become your best friend we use it for debugging we use it for printing

information to the screen um for logging to to streams to files it is used everywhere in Python now it's a bit more

functional than just printing a single string what you can do you can print several things at once so you can go

print and we can go hello the number 12 um sunny day some random thing so we have two strings and a and a number 12

here what happens when we print so it prints the first thing hello then it prints the number and then it prints the

next string we could for example go instead of this we can go hello

world yeah so it printed hello world here and we can manipulate the way that it prints these things so for example we

can say that we want each of these individual components separated by a character so we can go add a parameter

called SE and we want this to be separated by a comma and a space okay so it's going to print the first bit then

it's going to print the comma in the space and then it's going to present and print the second bit so if we run this

see we have our hello world program written in one line using several different strings and a separator in the

example above where we printed Hello World Learning python is fun yay it's a nice day to Learn Python you see it

printed each one of these line by line what happens if we don't want to print it line by line but if we want something

to print a little bit and then print something else but all on the same same line now there's a command another

parameter in print called end so we can go print this is the first

line print this is the second part and let's make this part okay so what's going to happen here

it's going to print this is the first part this is the second part on two separate lines as we've seen before here

we go now if we want them on the same line you see at the end of each print command it goes to a new line if we

don't want this to happen we say end and here it defaults to next line but we can simply put whatever we want to happen at

the end so we can go a hyphen so this is going to print this is the first part then a hyphen and then this is the

second part you see so it prints it all on one line because we're no longer going to the next line as it does by

default so here's a little exercise for you try to write the hello world program using two print statements you now have

all the tools you know about the separation you know about the end of line charact parameters try to use two

print statements to write the hello world program pause the video try it out and then come back for the

solution okay so hopefully that worked out the answer is actually quite straightforward so if we go print we can

go hello and the other part that we want to print is world right so instead of jumping to the next line we can simply

go end so at the end we we don't want to jump to the next line but we wanted to print a comma and a space so if we now

run this we have our old friend hello world changing the end characters this becomes super important when you start

tabulating your data if you have a lot of data and you want to print it in a certain format or you start printing to

files but you don't want to start a new line every time so print is a really really powerful command that's going to

become your best friend so now I've told you about the print command but what happens if you want to find these things

out yourself now python has a really neat function that's inbuilt that's called help okay so we can go help print

and print is the command that we want help about so we run this command help and inside here we write whatever we

want help on so we want help on the print function let's make this a little bit bigger run the command and there we

go so you see all of this is what the help command printed out help on built-in function print in module

built-ins and here you can see so it gives you the parameters that you can use yeah it gives you all the arguments

so these are the the hello in the world then it says you can use a separator by default it's a space you can use an end

of line by default it's a new line and then there are other parameters you can use for example file and flush but we'll

not get into those for now yeah so here it gives you a little description about what every little component does and how

to use the function properly so very powerful tool very helpful especially when you're starting out and you need

some more detailed information about the functions that you're using okay so that's the print function now something

about python is python is K sensitive and what that means you can see the way that we write the print function so

print is written all in lowercase but what happens if we try to run it uppercase if we go print with an upper

case p and here we write hello world and we try to run this again we get an error we get a name error so

it's this line that's giving us the error and we can know that is this line because it highlights the line for us it

even gives us line number it's line number 15 which it says here and it says print is not defined it doesn't know

what to do with this uppercase print because it only knows lowercase print and it's even smart enough to ask did

you mean print as in lowercase so make sure that when you write things that you always use the correct casee and

commands are always lowercase so if we change this back to lowercase we run it again we get our good friend hello world

so print is going to become your best friend the help function is going to become your second best friend both of

these are very very powerful tools okay so our script that we've started writing here is becoming a little bit long and

there's certain things that you've learned about separation about End of Line in the print command what happens

if you come back say 2 weeks later you're looking at the script and you don't don't really remember why you

wrote all of this code this is where commenting comes in commenting is really really important when it comes to all

kinds of programming whether it's python or whether you're writing apps for your mobile phone or whether you're

developing for the web commenting allows you to write bits of text in your code that explains what certain sections are

doing and that remind you of what you were thinking at the time in Python there two ways to Define comments the

first one is simply using a hashtag so if you use a hasht anything that comes after the hashtag is

going to be ignored so I can write this is a comment and when we run the command see we didn't see this comment printed

anywhere but it allows us to remember why we did certain things so if for example we no longer want this help

function that keeps taking up space to print we can simply put a hashtag in front of it now it becomes a comment

this is a really useful programming tool so rather than deleting stuff you make it a comment

because everything that comes after the hashtag is going to be ignored let me make this a little bit bigger if I run

the file again you see we no longer execute this command this command is now a comment everything behind it gets

ignored and this also means that we can put a comment after here um where we're saying just saying hello to the world

this bit again it's gr out it's going to be a good ignored another way to define comments in Python especially when

they're a little bit longer I'm just going to come to the top is to use triple quotes Okay so bit similar to the

hashtag anything that's inside these triple quotes is going to be ignored by the compiler it's going to be treated as

a comment so here we can write a really long comment uh this is the first script that I

wrote it's part of the Python course I am enjoying myself greatly this becomes really useful when you start

writing long scripts and you want to document what little sections do when you have complicated calculations you

can really explore what parameters do what certain functions do and it allows you to then later come back and

understand the code that you've written so commenting is really really key to writing clean code to writing readable

code that you can give to other people or that you can understand again and there you have it that was your

gentle introduction into basic python syntax we looked at how to write several print statements one underneath the

other and the compiler just goes through them how we can comment our code how we can change the way the print function

behaves and that it's case sensitive that python is case sensitive keep all of this in mind as you progress through

your python Journey now next time we're going to pick up the level a little bit we're going to start looking at

variables how can we Define variables variables keep data for us and how can we work with the different types of

variables till then Happy coding try some of these things out and I'll see you in the next video