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[no audio]

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Friends, using Python you can work with like text files, JSON

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files, CSV files, HTML files, and so on, and as of now here we

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are going to work with text files.

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So simply working with text files using Python.

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So guys before going to work with your text files using Python

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let's move into our general GUI procedure whenever if

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you want to create or read the content from your text file,

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right. See what I am doing is, suppose I want to create a

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new file, right,

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yeah, before that see guys, generally if you want to work with

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text files, right, you have three options.

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That is you can create a new file,

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or add content to an existing file, or just for reading purpose

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read a file content.

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Right. See, whenever if you are going with GUI procedure,

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I mean in this way, 'Right Click', 'New', then your file name,

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I mean, let me select my file as text file.

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I mean, I want to create file as text.

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Right. I'm creating,

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let's say file name as some 'demo.txt', right. Now

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I am going to open it. Observe that.

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I am going to open it. Open it.

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Yes, I opened. Right. See guys, in your GUI procedure

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whenever if you open your file, you can read your file,

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you can write content to your file, right, all the options

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are available simply by opening your file in GUI mode, but

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command line, or through programming, or through scripting,

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it's not possible.

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You have to open your file either to write content, or to

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read content, or to add some new data to the existing file.

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Be clear. See in GUI mode it is possible simply by opening your

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file, but whereas through programming if you want to work

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with your files, right, you have to open your file,

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you have to open your file either in 'write' mode, means if

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you want to create a new file, right, or you have to open

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your file in 'append' mode, means adding new content to existing

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file, then you have last option, that is 'read' mode, just to

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read. Right. See that. You can open your file -

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If you want to create a new file

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you have to open your file with the 'w' mode,

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or if you have already a file and if you want to add, append

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data to an existing file, then you have to open your file

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in 'append' mode,

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or simply if you want to read content from your file, you

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have to open it using 'r' mode. Right. Fine.

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And one more thing guys, once if you write some content to your

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file, right, see I'm opening, steps are important,

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I am opening, based on cursor position

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you are going to write content. Suppose if cursor is somewhere

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there, I am moving cursor to some place, then I can write.

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So wherever your cursor is there, based on that cursor only

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you are writing content to your file.

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[no audio]

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Fine. So assume that I am writing, "This is a demo file",

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and I am going to close it, while closing it is asking 'Save'

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option. But in programming in your Python Script, once if you

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close, automatically the data will save into your file.

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You don't need to provide confirmation like save or don't

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save. Whenever if you close, automatically your data will store

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into your file. Right. See now

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[no audio]

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I'm going to, see guys, whether you want to read a content,

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or whether you want to write a content to your file always you

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should get in your programming first your cursor position,

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or your file object.

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You can take any variable.

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I am taking 'fo', file object. Just assume that this is like

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your cursor position.

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So once if you get into your hand, cursor position, then after

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that whether you want to read or write you can do it.

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So now I want to get my cursor, right, to write content to

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your file. Then open your file in 'write' mode.

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Open your file in 'write' mode.

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Let's say 'newfile.txt'.

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I'm writing, then 'w' mode, 'write' mode.

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Then after that simply you can close.

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So as of now, what I am doing is simply I'm opening a file

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and then closing a file. While opening, right,

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I'm giving some file name. Automatically this file will be created

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with empty data.

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Now this is your cursor position. With cursor position

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nowhere I am writing any data to your file.

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Simply I'm closing.

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It's like creating an empty file, right?

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Let me check it.

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So this is simply

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[no audio]

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'Creation of empty file'. That's it.

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Let me open editor.

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So I am going to open my, you can take a Sublime or Atom editor,

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whatever it maybe you can take. I'm going to suppose, Sublime Text.

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Right. Let's open that first.

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[no audio]

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Let me create a file.

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So guys, first of all,

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right, so, "Working with

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[no audio]

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text files". You know to work with your

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text files you have different modes - write, read or append.

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First of all because we are going to create a new file,

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assume that we don't have any files to read,

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we need to create some file, right?

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So before going to create always in your hand you should

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have a cursor position from your file.

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That's why what I am doing is, first I'm going to open my

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file. Let's say some file, right, some 'newdemo.txt' file

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I am creating. So I want to open this in 'write' mode.

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So now this file I am opening for 'write' mode.

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So once you've opened your file automatically this syntax is going

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to give your cursor object, simply file object. That's it.

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Now based on this object

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you can write some content to your file.

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But what I am doing is, simply I opened my file, and then closed.

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Right. Let me save it. Be clear.

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[no audio]

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Let me save it with some name, right.

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So I'm going to store on my Desktop.

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[no audio]

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'create_a_file.py'. That's it.

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Now this is a Python Script.

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Now, what I am doing is, I am going to run our code. Just simply

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'Ctrl + B'

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[no audio]

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Done. Done.

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You don't have any output here because you don't have any

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'print' statement to get your output, right.

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Simply we created a file.

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Let me open our folder.

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[no audio]

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'create_a_file', just now we created this. Let me, sorry,

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that is a Python Script,

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right. So our file name is 'newdemo'.

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[no audio]

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Yeah, see here, 'newdemo.txt'. Open this. You don't have

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any content because you just opened and closed your file, okay.

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Okay, we'll write our data to your file,

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but before that suppose I want to see in which mode your

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file is opened.

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You can check it simply 'print(fo.mode)'.

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So it is going to give you the mode of your file 'write'

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mode. Right. Then,

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let me comment this. Now,

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you can check it, 'fo.readable'.

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Observe the output, what you are getting. Yeah, this is a function.

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Let me run it, 'False'

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you are getting. That means you opened your file not for read,

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some other thing, maybe write mode or append mode. That we

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have seen by using 'fo.mode'.

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So 'fo.readable', it is going to give 'False' means you

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can't read the content if you open your file with 'w' mode, that's it.

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Let me print one more thing, 'fo.

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writable'. Yes, 'True'

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you're getting. Yes,

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we can write some content to this file.

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Actually, no need to check this.

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Yes, there are some options

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that's why I am giving this. Right.

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Now, let me comment this entire code.

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[no audio]

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Be clear. Now,

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what I am doing guys? I want to write a file. Then first open

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with some name, random name,

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you can take anything, right?

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I am taking suppose 'random.txt'.

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So you want to write to a file at very first time, you don't

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have any file previously, assume that. Then open it in 'write'

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mode. So whenever if you open with this syntax automatically

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your Python will give your file object.

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Assume that there is like a cursor

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in your Notepad.

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Yes, now in your hand you have a cursor position, then what I want

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to do is I want to write some content. Then based on your

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cursor position just '.write' operation.

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Let me write, "This is a first line", I am writing.

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Then after that close it.

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So guys what we did is just we have written three lines of

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code to create a file and to write some content into that

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file. Now if you run this code then only your file will create.

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You have written a Python Script just to create your file

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with content of, "This is a first line".

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Right. Let me save it and run it. It's done.

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Right. Let me go to here. Somewhere

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you will have 'random'. See that.

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Let me open this file.

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"This is a first line".

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Guys, what I am doing is,

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I'm going to write one more line. 'write("

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This is a second line").

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Let me save it and run it.

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[no audio]

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Open your file and see the content.

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"This is a first line".

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"This is a second line".

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You're getting both the lines in the same line in your file.

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But actually that is not our requirement.

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We need to get, "This is a first line" in one line,

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"This is a second line" in next line. But whenever if you want

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to, whenever if you want to send the next line into next line

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at the end of each and every line you have to write '\n'

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so that your cursor will go to next line.

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I mean generally you know, suppose assume that you are going

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to write some content in any file, right,

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so what I'm doing is manually I'm typing,

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[no audio]

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"This is a line".

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Guys, if I want to write content to next line what I am doing,

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I am entering my 'Enter' key on my keyboard, right, then only

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your cursor is going to next line.

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That's what I am doing here with help of '\n'. For last line,

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suppose if this is last line you don't need to send your cursor

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to the next line. That's it.

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Let me save it and run it. So before run let me close this

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file. Yeah, let me run it.

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Now open your file, check the content. Now you have, "This is

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a first line" in one line.

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"This is a second line" in next line, right.

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So automatically your cursor is sending to next line. Suppose

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if I want to write one more line, 'write(, then, "This is a third

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line")'. I am writing. So guys not only here, before writing your

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third line also you can send your cursor to the next line. '\n' means

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simply your cursor will go to next line. In next line

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this content will write but providing '\n'

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at very first line is not a good practice,

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that's why always we mention at the end of your content

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'\n'. You need to remember this one.

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Let me save it and run it.

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[no audio]

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Sorry, where is your file? Here, 'random'. Open it and see the

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content. You have three lines. And one more thing guys,

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it's very important.

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I am running this code again

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and again. Let me run it

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once, I run second time, third time. Three times I run this

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script. But if you observe your content, right, if you observe

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your content, it is only three lines. So you can feel, I mean

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you are running your code three times then maybe your data

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will be there three times

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in your file, but it is not there in your file

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three times, it

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is there only one time. See you are not getting like this,

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no, you're running your program three times,

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then you're not getting your file in this way.

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Your data is not repeating three times in your file.

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It won't happen.

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See what actually it is doing, whenever if you open your file

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in write mode,

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it's very important,

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whenever if you open your file in write mode, if file is already

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there, then first of all your Python will simply remove

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this file and then same file name will be created.

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00:13:25,000 --> 00:13:30,300
If file is not there, new file is going to be created, or if file is not there

253
00:13:30,300 --> 00:13:33,300
it will create a new file, if file is already there your content

254
00:13:33,300 --> 00:13:38,100
we will overwrite, your content will overwrite. See that, suppose

255
00:13:38,100 --> 00:13:39,300
I am going to write here,

256
00:13:39,300 --> 00:13:41,100
[no audio]

257
00:13:41,100 --> 00:13:43,000
let me delete these two lines.

258
00:13:43,000 --> 00:13:45,800
[no audio]

259
00:13:45,800 --> 00:13:46,800
So what I am doing is,

260
00:13:46,800 --> 00:13:49,000
[no audio]

261
00:13:49,000 --> 00:13:50,800
"This is a new content".

262
00:13:50,800 --> 00:13:53,300
[no audio]

263
00:13:53,300 --> 00:13:56,700
Let me save it and run it. Done. Right. Now,

264
00:13:56,700 --> 00:13:57,700
see the content.

265
00:13:57,700 --> 00:14:00,600
[no audio]

266
00:14:00,600 --> 00:14:01,800
Your previous data is gone.

267
00:14:03,500 --> 00:14:06,100
Only new content is there. Previously you have three lines,

268
00:14:06,100 --> 00:14:08,500
right? But now you have only one line.

269
00:14:08,700 --> 00:14:12,100
The reason is, whenever if you open your file in 'write' mode

270
00:14:12,100 --> 00:14:15,100
simply you can assume that, if already file is there with

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00:14:15,100 --> 00:14:18,100
this name that file we'll delete and new, with the same name

272
00:14:18,100 --> 00:14:20,900
new file we'll create. If file is not there, first time

273
00:14:20,900 --> 00:14:22,500
you're going to create that file. That's it.

274
00:14:22,500 --> 00:14:24,300
[no audio]

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00:14:24,300 --> 00:14:25,800
Right. Fine.

276
00:14:26,200 --> 00:14:32,000
So guys here you are writing your content to your file one by one.

277
00:14:32,100 --> 00:14:35,100
I mean, suppose if I want to write three lines how you are

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00:14:35,100 --> 00:14:37,700
going to write? Three times you are using 'fo.write',

279
00:14:37,700 --> 00:14:39,100
'fo.write', 'fo.write'.

280
00:14:39,400 --> 00:14:42,500
No need of that. See what I am doing is, I am going to comment

281
00:14:42,500 --> 00:14:45,700
these three lines. Instead of that, instead of that

282
00:14:45,700 --> 00:14:48,600
[no audio]

283
00:14:48,600 --> 00:14:52,600
'fo.writelines', and here you have to provide your

284
00:14:52,600 --> 00:14:53,800
data as a list.

285
00:14:53,800 --> 00:14:56,700
[no audio]

286
00:14:56,700 --> 00:14:58,600
You can also store your data somewhere

287
00:14:59,800 --> 00:15:02,500
as a list, let's say 'my_content',

288
00:15:02,500 --> 00:15:05,100
[no audio]

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00:15:05,100 --> 00:15:08,300
that we have to take as a list. In that list each and every

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00:15:09,000 --> 00:15:10,200
value is one line.

291
00:15:10,300 --> 00:15:14,700
Let's say, "This is a data - 1", suppose.

292
00:15:15,100 --> 00:15:17,900
So at the end you have to add '\n', right.

293
00:15:18,200 --> 00:15:20,800
So if you don't add you can also take care while writing

294
00:15:20,800 --> 00:15:22,900
your content to your file with the help of loop.

295
00:15:22,900 --> 00:15:26,100
I will show you that. Meanwhile, first to get basic

296
00:15:26,100 --> 00:15:27,400
idea I am giving in this way.

297
00:15:28,400 --> 00:15:30,800
"This is a data - 2".

298
00:15:32,100 --> 00:15:35,600
Then, "This is a data - 3", suppose.

299
00:15:37,300 --> 00:15:40,200
Right. See if I don't add here '\n', what will happen?

300
00:15:40,600 --> 00:15:41,700
Let me save it.

301
00:15:42,600 --> 00:15:44,800
See guys, instead of writing line by line with the help

302
00:15:44,800 --> 00:15:49,000
of 'fo.write' function, right, 'fo.write' method,

303
00:15:49,100 --> 00:15:51,500
what we are doing is, 'fo.writelines'. Here

304
00:15:51,500 --> 00:15:54,300
you can provide your content as a list. Now

305
00:15:54,300 --> 00:15:57,200
our content is a list. Somewhere we have our list of content

306
00:15:57,200 --> 00:16:02,800
here. Let me save it and run it. Same file name 'random'.

307
00:16:02,800 --> 00:16:05,000
Previously you have this information, right. Now,

308
00:16:05,000 --> 00:16:08,100
what we did? We opened that file in 'w' mode.

309
00:16:08,100 --> 00:16:11,700
That means, if there is any file with the same name that content

310
00:16:11,700 --> 00:16:13,900
will delete or that file will delete and new content

311
00:16:13,900 --> 00:16:17,200
we will write to this file. Now

312
00:16:17,200 --> 00:16:19,700
let me go here and open your file. See that.

313
00:16:21,200 --> 00:16:22,200
"This is a data - 1".

314
00:16:22,200 --> 00:16:25,400
"This is a data - 2". "This is a data - 3". In case if you want to

315
00:16:25,400 --> 00:16:29,400
send "This is a data - 3" to next line, what you have to do? At

316
00:16:29,400 --> 00:16:31,200
the end of your second line

317
00:16:31,200 --> 00:16:32,400
you have to write '\n'.

318
00:16:34,000 --> 00:16:37,400
Right. Fine. But providing '\n' at

319
00:16:37,400 --> 00:16:40,800
the end of each and every line it's not a good practice. Automatically

320
00:16:40,800 --> 00:16:43,800
you need to add '\n' for each and every line, right?

321
00:16:44,000 --> 00:16:47,400
So for that what I am doing is, now let me comment all these things.

322
00:16:47,400 --> 00:17:00,400
[no audio]

323
00:17:00,400 --> 00:17:01,400
Give me a second.

324
00:17:03,200 --> 00:17:05,098
Now I am going to write the different file name.

325
00:17:05,200 --> 00:17:06,598
I don't want you same file name.

326
00:17:07,000 --> 00:17:08,400
Of course, you can use it, no problem.

327
00:17:09,000 --> 00:17:12,200
Let me take first of all 'my_content' as something like

328
00:17:12,200 --> 00:17:14,000
[no audio]

329
00:17:14,000 --> 00:17:16,200
"This is using loop".

330
00:17:16,200 --> 00:17:18,300
Let me take, "- iteration- 1".

331
00:17:18,300 --> 00:17:20,200
[no audio]

332
00:17:20,200 --> 00:17:21,200
Then,

333
00:17:22,800 --> 00:17:28,400
"This is using loop - iteration- 2".

334
00:17:30,000 --> 00:17:32,599
Let me copy this data one more time.

335
00:17:32,599 --> 00:17:34,400
[no audio]

336
00:17:34,400 --> 00:17:36,000
Right. See that.

337
00:17:37,099 --> 00:17:40,200
So what I am doing is, this is a text, right,

338
00:17:40,900 --> 00:17:43,200
so let me take this as 3. Now,

339
00:17:43,200 --> 00:17:44,099
first of all guys,

340
00:17:44,300 --> 00:17:49,300
first of all I can take one by one value from your list

341
00:17:49,300 --> 00:17:50,300
using for loop, right?

342
00:17:50,400 --> 00:17:53,800
If you remember 'for each_line', let me take, you can take any

343
00:17:53,800 --> 00:17:56,300
variable here 'for each_line in my_content'.

344
00:17:57,200 --> 00:18:00,100
Right. See what I am doing, 'print(each_line)'.

345
00:18:00,700 --> 00:18:03,900
Save it. Run it. You're getting one by one line.

346
00:18:04,800 --> 00:18:07,100
Now before printing your line, at the end

347
00:18:07,100 --> 00:18:11,700
I am adding '\n'. You have no problem. You can add it no. Yes.

348
00:18:13,000 --> 00:18:16,300
Now, what I am doing is I want to create a file with this

349
00:18:16,300 --> 00:18:18,700
content, whatever the content you have in your list.

350
00:18:19,400 --> 00:18:21,300
So I want to create a file called,

351
00:18:22,400 --> 00:18:26,200
let's say, 'with_loop.txt'.

352
00:18:27,100 --> 00:18:28,400
I want to create this file.

353
00:18:28,400 --> 00:18:30,400
So open in 'write' mode.

354
00:18:31,400 --> 00:18:33,500
So it is going to give a file object.

355
00:18:33,700 --> 00:18:34,900
Actually, that is a class,

356
00:18:34,900 --> 00:18:36,700
okay. As of now, you can't understand that.

357
00:18:37,000 --> 00:18:41,400
Just assume that 'fo' is a cursor. Just for your understanding

358
00:18:41,400 --> 00:18:44,800
purpose I am giving 'fo' as a cursor guys, right. If you assume

359
00:18:44,800 --> 00:18:47,400
that it is going to work the same operation whatever your

360
00:18:47,400 --> 00:18:49,000
cursor is doing in GUI mode.

361
00:18:49,500 --> 00:18:53,200
So just now we got into our hand cursor position of this file.

362
00:18:54,000 --> 00:18:55,000
Now what we have to do,

363
00:18:55,600 --> 00:19:01,800
we want to write line by line content to your 'with_loop.txt' file.

364
00:19:01,900 --> 00:19:04,300
See, you know, if you have one single line how you're going

365
00:19:04,300 --> 00:19:08,800
to write your data, 'fo.write'. That's it.

366
00:19:09,200 --> 00:19:13,000
See what I am doing is, automatically I am taking line by

367
00:19:13,000 --> 00:19:17,000
line from your list, and I am writing that line to your file

368
00:19:17,000 --> 00:19:20,500
with the help of 'fo.write' method, and then while writing

369
00:19:20,500 --> 00:19:24,400
at the end of each and every line I am adding '\n'. Now

370
00:19:24,400 --> 00:19:27,100
no need to manually write '\n' at the end of each

371
00:19:27,100 --> 00:19:27,900
and every line, right?

372
00:19:28,700 --> 00:19:32,000
Actually, this is not a practice, good practice because you are going

373
00:19:32,000 --> 00:19:34,900
to get your data from somewhere, there maybe number of

374
00:19:34,900 --> 00:19:36,900
lines, right?

375
00:19:37,200 --> 00:19:40,500
So logically you need to '\n' at the end of your each

376
00:19:40,500 --> 00:19:43,300
and every line while adding that data to your file, that's it.

377
00:19:44,800 --> 00:19:48,800
Right. So after this what you have to do? You completed your for

378
00:19:48,800 --> 00:19:50,700
loop suppose. For three iterations

379
00:19:50,700 --> 00:19:53,400
this loop is going to over. Then after loop

380
00:19:53,400 --> 00:19:55,200
don't forget to close your file.

381
00:19:55,800 --> 00:19:59,700
Once if you close your file, automatically the data will store,

382
00:20:00,000 --> 00:20:03,200
will save into your file called 'with_loop.txt' file.

383
00:20:03,900 --> 00:20:05,700
Let me save it and run it.

384
00:20:06,700 --> 00:20:11,200
Done. Now go to here. Somewhere see 'with_loop'

385
00:20:11,200 --> 00:20:13,700
is there. Open that. See that.

386
00:20:13,700 --> 00:20:15,800
[no audio]

387
00:20:15,800 --> 00:20:17,100
Right. Fine.

388
00:20:17,600 --> 00:20:21,700
See guys, suppose if you have some file somewhere, old file

389
00:20:21,700 --> 00:20:25,300
is there, and you don't want to disturb the existing data,

390
00:20:25,300 --> 00:20:28,400
and you want to append the new data to your file then nothing

391
00:20:28,400 --> 00:20:33,600
is there. Simply open your file in mode, 'a', 'append'. At the end

392
00:20:33,600 --> 00:20:35,200
you are going to add new data.

393
00:20:35,200 --> 00:20:37,200
[no audio]

394
00:20:37,200 --> 00:20:40,900
Right. Let me save it and run it once. See guys, previously you

395
00:20:40,900 --> 00:20:44,200
have the content in your file, three lines content.

396
00:20:45,000 --> 00:20:48,700
Now, what I am doing is I am opening my file in 'append' mode. Whenever

397
00:20:48,700 --> 00:20:52,400
if you open your file in 'append' mode if this file is existing,

398
00:20:52,600 --> 00:20:54,500
it won't disturb the existing data.

399
00:20:54,500 --> 00:20:58,700
It will keep the data as it is. Then the new data will be appended

400
00:20:58,800 --> 00:21:00,000
at the end of your file.

401
00:21:00,300 --> 00:21:01,300
So same content

402
00:21:01,300 --> 00:21:03,500
I want to add once again to my file.

403
00:21:04,400 --> 00:21:09,100
Yes, just open in 'append' mode, right. See that. I'm running.

404
00:21:10,000 --> 00:21:12,000
It's done. Now open your file.

405
00:21:12,000 --> 00:21:13,900
[no audio]

406
00:21:13,900 --> 00:21:17,500
See that. Your data is there two times. Once again, you can

407
00:21:17,500 --> 00:21:21,400
run, so that once again the same data you're going to append

408
00:21:21,400 --> 00:21:24,600
at the end of your file. Now three more extra lines.

409
00:21:24,600 --> 00:21:25,800
Let me open that file.

410
00:21:27,500 --> 00:21:32,600
Yes. Right. Fine. Now assume that we don't have this file.

411
00:21:33,100 --> 00:21:34,700
Let me remove this file.

412
00:21:34,700 --> 00:21:37,000
[no audio]

413
00:21:37,000 --> 00:21:41,600
Guys, whenever if you try to append a data to this file, if

414
00:21:41,600 --> 00:21:45,500
it is there then the new data will be appended at the end. If

415
00:21:45,500 --> 00:21:46,800
it is not there, no problem

416
00:21:46,800 --> 00:21:48,700
your Python will create a new file now.

417
00:21:49,400 --> 00:21:53,500
So if file is not there then 'append' mode and 'w' mode both are same.

418
00:21:55,000 --> 00:21:58,600
If file is not there 'append' mode and then 'write' mode both

419
00:21:58,600 --> 00:21:59,900
are same. Now

420
00:21:59,900 --> 00:22:01,600
let me save it and run it.

421
00:22:01,800 --> 00:22:05,400
I am running. It's done without any errors means, it worked

422
00:22:05,400 --> 00:22:07,600
perfectly. Let me open your file.

423
00:22:07,600 --> 00:22:11,800
See now you've got 'with_loop' file, three lines of content. Now,

424
00:22:11,800 --> 00:22:12,800
I am going to rerun.

425
00:22:12,800 --> 00:22:15,800
[no audio]

426
00:22:15,800 --> 00:22:17,600
So already 3 lines of information is

427
00:22:17,600 --> 00:22:20,300
there no, because of this for loop. Same content you are going

428
00:22:20,300 --> 00:22:23,600
to write once again, three lines of information, right?

429
00:22:23,600 --> 00:22:25,400
Let me open it and see the result.

430
00:22:27,000 --> 00:22:29,400
So that is the use of your 'append' mode.

431
00:22:30,300 --> 00:22:33,400
That is the use of your 'append' mode. That's it.

432
00:22:34,400 --> 00:22:38,100
So guys, this is the way how you can create a new file or

433
00:22:38,100 --> 00:22:41,600
how you can append new content to your existing file.

434
00:22:43,100 --> 00:22:44,300
Right. Fine.

435
00:22:44,400 --> 00:22:47,700
Now, what I want to do is, I have some file, right. Already

436
00:22:47,700 --> 00:22:50,100
we know we have file called 'with_loop.txt'.

437
00:22:50,100 --> 00:22:52,700
Now, I want to read the content using your Python.

438
00:22:53,400 --> 00:22:55,800
I want to read the content using your Python.

439
00:22:56,100 --> 00:22:59,700
Nothing is there. First whether you want to read or write your content

440
00:22:59,700 --> 00:23:02,700
with your Python, first of all you have to open your file,

441
00:23:02,700 --> 00:23:09,100
but while opening your file, right, you have to write your required

442
00:23:09,100 --> 00:23:12,600
mode here, whether you want to write or read. Now my purpose is,

443
00:23:12,600 --> 00:23:13,700
I want to see the data,

444
00:23:13,700 --> 00:23:16,800
I want to read the data, then open your file in 'read' mode.

445
00:23:17,800 --> 00:23:21,800
That's it. So whether you're going to write your content to your file

446
00:23:21,800 --> 00:23:25,500
or whether you are going to read content from your file you

447
00:23:25,500 --> 00:23:27,200
have to do one thing open and close.

448
00:23:27,200 --> 00:23:28,400
Don't forget about this.

449
00:23:28,800 --> 00:23:33,100
If you don't close, then sometimes your file may corrupt.

450
00:23:34,800 --> 00:23:35,800
Right. Fine.

451
00:23:36,000 --> 00:23:38,300
Now, I opened in 'read' mode.

452
00:23:38,300 --> 00:23:40,000
I closed it, right.

453
00:23:40,100 --> 00:23:41,100
Let me execute it.

454
00:23:42,200 --> 00:23:45,700
No error. No output. Whenever if you are reading means, you should

455
00:23:45,700 --> 00:23:49,000
display something then only you can see the content. Now,

456
00:23:49,000 --> 00:23:50,900
how can I display the content? Nothing

457
00:23:50,900 --> 00:23:54,100
is there. Simply 'print(fo.read)'.

458
00:23:55,300 --> 00:23:59,500
'fo.read'. See the content. You're going to get your entire

459
00:23:59,500 --> 00:24:02,100
data at a time using 'fo.read' operation.

460
00:24:02,900 --> 00:24:05,400
You can also store these into one variable called,

461
00:24:05,400 --> 00:24:09,400
let me take 'data', data of your file.

462
00:24:09,400 --> 00:24:11,500
[no audio]

463
00:24:11,500 --> 00:24:14,200
That's it. After closing your file

464
00:24:14,400 --> 00:24:17,300
you have your data in a 'data' variable.

465
00:24:18,000 --> 00:24:22,800
That's it. See I opened, I read the data, and I stored into some

466
00:24:22,800 --> 00:24:25,700
variable called 'data'. Now, even though if you close your file,

467
00:24:25,700 --> 00:24:29,000
already we stored the file content to some variable, that

468
00:24:29,000 --> 00:24:30,100
variable we can use it.

469
00:24:30,100 --> 00:24:32,800
[no audio]

470
00:24:32,800 --> 00:24:34,200
Right. Fine.

471
00:24:34,200 --> 00:24:37,100
So at a time if you want to read your entire content, this

472
00:24:37,100 --> 00:24:38,100
is the procedure.

473
00:24:38,300 --> 00:24:41,300
Now, what I want to do is I want to read one by one line.

474
00:24:42,700 --> 00:24:43,700
One by one line

475
00:24:43,700 --> 00:24:46,700
I want to read. See that. What I am doing.

476
00:24:46,900 --> 00:24:49,700
Anyway, if you want to read always you have to open your

477
00:24:49,700 --> 00:24:50,700
file in 'read' mode.

478
00:24:51,200 --> 00:24:54,800
Then 'fo.readline'. That's it.

479
00:24:55,600 --> 00:24:59,700
Then let me close it and see the content what you are going to get.

480
00:25:00,600 --> 00:25:04,000
Sorry. You read the data, but you need to print that, right,

481
00:25:04,000 --> 00:25:05,100
then only you can see the data.

482
00:25:06,500 --> 00:25:08,800
'print', whatever the data you are reading.

483
00:25:10,000 --> 00:25:13,900
That's it. This is a, "This is using loop- iteration- 1". Now

484
00:25:13,900 --> 00:25:16,800
I want to read second line, then immediately do once again

485
00:25:16,800 --> 00:25:17,900
your 'readline'.

486
00:25:18,900 --> 00:25:19,900
That's it.

487
00:25:21,200 --> 00:25:24,400
But reading line-by-line, I do not know how many lines you

488
00:25:24,400 --> 00:25:25,400
have in your file.

489
00:25:26,600 --> 00:25:29,900
Right. So this is not a good practice to read your file.

490
00:25:31,100 --> 00:25:34,300
But you have an option. Sometimes, very rare cases you will

491
00:25:34,300 --> 00:25:38,800
use this one also. But remember that usage as well. Now, I

492
00:25:38,800 --> 00:25:41,300
want to read your entire content at a time.

493
00:25:42,500 --> 00:25:45,100
So previously whatever the data you are reading with the

494
00:25:45,100 --> 00:25:49,800
help of 'fo.read', right, see that, let me enable this once.

495
00:25:48,100 --> 00:25:56,400
[no audio]

496
00:25:56,400 --> 00:25:57,800
Let me 'print(data)'.

497
00:25:58,100 --> 00:26:01,000
And what is the data you are having in that? You know, you

498
00:26:01,000 --> 00:26:02,600
have a data, your data, right?

499
00:26:02,800 --> 00:26:03,800
See the output.

500
00:26:03,800 --> 00:26:04,900
What is the type of your data?

501
00:26:04,900 --> 00:26:05,900
That is a string.

502
00:26:05,900 --> 00:26:07,900
[no audio]

503
00:26:07,900 --> 00:26:10,700
Right, your string. You have number of lines in your file.

504
00:26:11,200 --> 00:26:13,900
I want to take line-by-line separately, but I want to read

505
00:26:13,900 --> 00:26:15,400
at a time all the lines.

506
00:26:16,900 --> 00:26:19,900
I want to read all the lines at a time, but I want to take

507
00:26:20,000 --> 00:26:22,300
line-by-line separately, not like a string.

508
00:26:22,300 --> 00:26:24,300
[no audio]

509
00:26:24,300 --> 00:26:25,200
See what I am doing.

510
00:26:25,200 --> 00:26:29,200
What I am doing here is, you have one more option just to read

511
00:26:29,300 --> 00:26:30,800
your entire content.

512
00:26:30,800 --> 00:26:32,600
[no audio]

513
00:26:32,600 --> 00:26:36,600
into a list. First of all, let me open my file,

514
00:26:36,600 --> 00:26:40,300
[no audio]

515
00:26:40,300 --> 00:26:48,100
then let me take 'data=', your 'fo.readlines'.

516
00:26:48,100 --> 00:26:49,600
It's very, very important.

517
00:26:50,200 --> 00:26:52,000
It is very useful in your real time.

518
00:26:53,500 --> 00:26:56,400
Now, let me print your data, and see the output what you are

519
00:26:56,400 --> 00:26:58,000
going to get. You're getting as a list.

520
00:26:59,700 --> 00:27:02,400
You're getting as a list. If it is a list, you know, you can

521
00:27:02,400 --> 00:27:05,700
take for loop, and you can print line by line. Suppose

522
00:27:05,700 --> 00:27:08,700
I want to read, simply I'm giving. If I want to read first three lines,

523
00:27:09,000 --> 00:27:10,700
What I will do is, see that.

524
00:27:10,700 --> 00:27:13,700
[no audio]

525
00:27:13,700 --> 00:27:16,800
'for each in range(3)'.

526
00:27:18,400 --> 00:27:19,400
First let me print

527
00:27:19,400 --> 00:27:20,900
what is the 'each' value you are getting.

528
00:27:22,600 --> 00:27:26,500
There is no relation as of now between your for loop and

529
00:27:26,500 --> 00:27:27,600
your data. Simply

530
00:27:27,600 --> 00:27:31,100
I am taking some 'range(3)', it is going to print 0, 1, 2.

531
00:27:32,800 --> 00:27:36,700
Right. Now this data is a list, right. In list

532
00:27:36,700 --> 00:27:40,800
if you want to read first three values, then index values

533
00:27:40,800 --> 00:27:44,100
are from 0 to 2, right, 0, 1, 2.

534
00:27:44,400 --> 00:27:47,200
So if we take 'range(3)', you are getting your required

535
00:27:47,200 --> 00:27:50,600
index values for your list to get your top three lines.

536
00:27:51,100 --> 00:27:55,500
Now, what I am doing is I am printing your 'data', then index value.

537
00:27:55,500 --> 00:27:57,400
[no audio]

538
00:27:57,400 --> 00:28:00,300
Guys, for first iteration your 'each' is equal to 0. That means

539
00:28:00,300 --> 00:28:04,800
you are printing simply 'data[0]'. Then second iteration

540
00:28:05,100 --> 00:28:07,800
you are getting index value as 1, third iteration

541
00:28:07,800 --> 00:28:10,200
you are getting index value as 2.

542
00:28:11,600 --> 00:28:14,500
That's it. This is the data you're going to print using your for loop.

543
00:28:14,500 --> 00:28:16,800
That means, you're getting top three lines.

544
00:28:16,800 --> 00:28:18,900
[no audio]

545
00:28:18,900 --> 00:28:19,900
Run it.

546
00:28:19,900 --> 00:28:22,200
[no audio]

547
00:28:22,200 --> 00:28:25,700
Right. So guys, now what I want to do is I want to get only last

548
00:28:25,700 --> 00:28:29,700
line. I want to get only last line, how can I get it? You know,

549
00:28:29,700 --> 00:28:31,700
[no audio]

550
00:28:31,700 --> 00:28:32,700
'data[]',

551
00:28:33,300 --> 00:28:37,500
last line, always. Already 'data' is a list, right.

552
00:28:37,500 --> 00:28:40,800
In list, last value index in terms of negatives,

553
00:28:41,100 --> 00:28:43,700
right, -1. Then I can print this one.

554
00:28:45,200 --> 00:28:46,600
Let me comment your for loop.

555
00:28:46,600 --> 00:28:52,300
[no audio]

556
00:28:52,300 --> 00:28:53,300
That's it.

557
00:28:53,300 --> 00:28:57,100
[no audio]

558
00:28:57,100 --> 00:28:58,400
Right. So guys,

559
00:28:58,400 --> 00:29:00,600
this is the usage with 'readlines'.

560
00:29:00,900 --> 00:29:05,100
We have so many real time cases, right. This is just introduction.

561
00:29:05,100 --> 00:29:09,000
We will see some simple real time example in next video.

562
00:29:10,300 --> 00:29:14,200
Okay. So guys finally you have to remember that, right.

563
00:29:14,600 --> 00:29:15,800
See 'write' mode, yeah.

564
00:29:15,800 --> 00:29:18,800
While working with your files you have three options.

565
00:29:19,600 --> 00:29:22,700
First option is you're going to create a new file. First time

566
00:29:22,700 --> 00:29:25,100
you are going to create. Then open in 'w' mode.

567
00:29:26,100 --> 00:29:29,700
So while opening your file in this mode, if already file is

568
00:29:29,700 --> 00:29:32,600
there then what it will do? Your Python is going to delete

569
00:29:32,600 --> 00:29:36,400
that file and is going to create a new file. So that, what

570
00:29:36,400 --> 00:29:40,500
will happen? Old file information will be deleted. So be careful

571
00:29:40,500 --> 00:29:43,100
whenever if you are opening your file in 'w' mode.

572
00:29:44,800 --> 00:29:50,200
I want to keep old content as it is and I want to add new

573
00:29:50,200 --> 00:29:54,400
content, I want to append new content to your file,

574
00:29:55,200 --> 00:29:59,500
then you have to open that in 'append' mode. Now,

575
00:29:59,500 --> 00:30:02,200
I want to read all the content which is there in my file,

576
00:30:02,200 --> 00:30:03,300
then open in 'read' mode.

577
00:30:03,800 --> 00:30:08,600
So whether you are going to write, append, or read, right, procedure

578
00:30:08,600 --> 00:30:09,700
is same. See, 'write',

579
00:30:09,700 --> 00:30:13,100
'fo', file object, open your file, and get into your hand your

580
00:30:13,100 --> 00:30:17,800
cursor. Do your logic here. Finally close your file. That's it.

581
00:30:17,800 --> 00:30:19,800
[no audio]

582
00:30:19,800 --> 00:30:22,200
Right. Fine.

583
00:30:23,400 --> 00:30:25,400
Okay guys, thank you for watching this video.

584
00:30:25,400 --> 00:30:39,424
[no audio]