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Hello and welcome to this video.

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Comments are very important in programming.

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They are used to tell you what something does in English.

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And they are also used to disable or deactivate parts of your program for testing purposes or parts

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that you want to eventually remove from your program.

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And in python there are two ways you can implement comments in your program code.

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The first is known as a single line comment.

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If you want to comment out is single line at a time you use the hash symbol.

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We also have the multi line comments.

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If you want to implement or comment out multiple line of code you used the three quotes three quotations.

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And that will comment out the block of code you have specify the comments to take out.

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So let's take a look at how comments work so I have got some lines of code inside my text editor I'm

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using item.

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This is a file here that I am referring to inside my text editor.

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So these are just a bunch of print statements that or print these text on to the console.

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So I've also got my command prompt open here on the bottom and my command prompt is basically where

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the code will be output head.

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So to be displayed in the console here.

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So notice here I've changed directory to my desktop because the desktop is where this file is.

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This is the file I'm referring to.

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If you are on a Mac you need to type in Python 3 followed by the name of your app before you can run

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it.

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The reason for that is the Mac has bought Python 2 which is pre installed.

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And then the Python 3 which you would have installed so you always have to specify which version of

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Python you're referring to on the Mac.

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So let me printout this program here.

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What's inside this file.

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Just by calling the file name which is this I just say my app dot P A Y course is a python file an hour

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press enter.

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I can see hear it as displayed the output from here displaying what's in here.

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That's the first line.

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This is the last line here.

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So let's say I don't want the first line to be displayed.

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I want to take out the first two lines and the way we do that.

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Just add a comment.

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Just use that he can see comments out that line completely.

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And if I want to take out the second line as well I just put the hash and that he can see the coloration

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has also change.

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And that takes out those two lines.

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So let me just save that and if I run the program again just by moving the up arrow on my keyboard that

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will run it again.

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I just PRESENTER Now you can see it starts from here on line three.

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That's the text there.

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It's not displayed.

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Line 1 and 2.

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You can see no line 1 and 2 here.

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Start from line 3 which is this one.

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And on line 6 which is that one.

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So that's how you implement a single line comment.

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If you want to comment out a single line of code.

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Also when you comment when you comment out a line of code you can also write some text just to if you

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want to be more descriptive of what it does.

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Now you can also have comments that will not impact on the code running.

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So for example line three here.

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Let me minimize the screen.

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Let me clear this to create some space.

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Clear that and minimize that.

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So let's say on line three here I want to add a comment so I can either comment if you comment on the

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right hand side.

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It does not impact on the code.

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It will not affect that.

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You can see it hasn't changed the appearance or the background color.

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All right.

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So we the idea of putting a comment on the right hand side is that you can then add some text to say

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what this line does.

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So I can see this line prints this blah blah blah.

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So it's just I can then add the descriptive text as to what that line of code does.

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So that's how you work with single line comments.

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So I'm just going to take that out the single line comment and take this one out as well.

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Now we have the multiple line comment.

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So let's say you want to I want you to comment out multiple lines.

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So let's come here.

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So you just two one two three has to be three and then I come here on the bottom and I do one two three

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so you can see everything here has turned green.

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You can see the print here is no longer highlighted as blue because everything here is now commented

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out.

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So this is I'm commenting out multiple lines of code at the same time.

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So let me save this and then try and run it again in my console.

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So again I just type in the name of the app my app dot p y and it should only run the first two line

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of code and that's because the other lines are being commented out.

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OK.

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So this three speak this three here quotes and the three here.

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That's how you two a multiple line comment.

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And you can also add text to that to describe what you are commenting out.

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So comments are very useful if you don't want the code to be affected.

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You can obviously use single line comments to comment out on the right hand side.

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What that line of code does or you can add multiple line comments and then just write some descriptive

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text of what that block of code is doing or is meant to do so.

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Comments are very useful because there may come a time you may want to test set in aspects of your code.

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You don't want that block of code to run and the way you do that is to just comment out either.

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That line of code or the entire block of code and that will prevent that section from executing when

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the code runs.

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So that's it for this video on using comments in Python.

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Thanks for watching and bye for now.