R/C2/Introduction-to-R-script/English-timed

Time	Narration
00:01	Welcome to this tutorial on Introduction to R script.
00:06	In this tutorial, you will learn
00:09	How to work with an R script in RStudio
00:14	To understand this tutorial, you should know basic commands of R.
00:21	If not, please locate the relevant tutorials on R on this website.
00:28	This tutorial is recorded on
00:32	Ubuntu Linux OS 16.04
00:37	R version 3.2.3
00:42	RStudio version 1.1.456
00:48	Install R version 3.2.0 or higher.
00:54	An R script is a plain text file in which you save your R code
00:01	Script allows you to show your work to others, and also reproduce and modify the results
01:10	Before you begin please create a folder named myProject on Desktop.
01:17	I have already created this folder on my Desktop.
01:23	I shall now save all my scripts and data sets in this folder.
01:30	Later, I shall set this folder as my Working Directory.
01:37	Let us switch to RStudio.
01:40	We will close these two tabs named Untitled1 and R packages available.
01:49	Click on the small cross symbol next to these tabs
01:55	We will now create a new R script.
01:59	In the top left corner of RStudio, click on the green plus sign.
02:05	Now from the dropdown menu, select R Script.
02:11	A new R script appears in the Source window.
02:17	You can also create a new R script by pressing Ctrl+Shift+N together.
02:24	Let us save this R script first.
02:28	In the top left corner of the screen, click on the File option.
02:36	Then click on Save to save the script.
02:40	Select the directory where you want to save your R script.
02:46	I am saving the script in the folder myProject on my Desktop, with the name myfirstscript.
02:56	Finally, click on the Save button.
03:01	Now you can see that the file is named as myfirstscript.R.
03:07	RStudio automatically adds dot R at the end of the filename.
03:15	Now, let us write some lines of code in the script file myfirstscript.R.
03:23	We will create a vector named testSample with one two three four as its elements.
03:33	We have already learned how to create vectors earlier in this series.
03:39	In the Source window, type testSample space less than symbol. Now type hyphen space c 1 comma 2 comma 3 comma 4 in parentheses. Press Enter
03:59	You may also use equal sign in place of less than symbol followed by hyphen.
04:08	In the Source window, to the left of the checkbox Source on Save, click on the Save icon Or, press Ctrl+S together to save the file.
04:22	We will now use the print function to display the values in testSample vector.
04:30	In the Source window, type p r i
04:35	RStudio automatically starts suggesting different functions.
04:41	You can navigate this list of functions by using the up (↑) and down (↓) arrow keys on the keyboard.
04:50	To select a particular function, just press Enter.
04:56	Finish typing print testSample in parentheses and press Enter.
05:04	Now let’s save the file and run it with these two lines only.
05:11	Now, we maximize the Source window.
05:15	In the top right corner of the Source window, click on the Source button.
05:22	You can see the line-by-line execution of the script in the Console.
05:29	You can also run the script by pressing Ctrl+Shift+Enter together.
05:36	For this, you need to first click in the script window.
05:42	Now let’s declare a variable firstVar with value of ten in the Source window.
05:50	Type firstVar with capital V space equal sign space 10 and press Enter.
06:00	Please note that R language is case-sensitive.
06:05	We will now use the print function to show the value of firstVar.
06:11	In the Source window, type print.
06:16	I am typing only p r i n but the options appear and I select print from there.
06:28	Now in parentheses, start typing firstVar.
06:32	RStudio shows firstVar; press Enter to select it.
06:39	Press Enter to go to the next line.
06:43	Now let’s declare another variable secondVar with value of fifteen.
06:50	In the Source window, type secondVar space equal sign space 15 and press Enter.
07:01	Now, as shown before, type print secondVar in parentheses to show its value and press Enter
07:13	We can add comments to our code by using # hash symbol followed by our comment.
07:22	Type hash symbol space Creating an R script before the declaration of testSample vector.
07:32	R interprets each line of code.
07:36	Please make sure that your comment and the first line of code appear in separate lines.
07:46	Now, let’s comment the line print(secondVar).
07:50	To do that, first click on this line.
07:56	Then from the top menu bar of RStudio, click on the Code option.
08:04	From the dropdown menu, click on the Comment/Uncomment Lines option.
08:10	This option helps us to comment as well as uncomment a line.
08:17	On doing so, we see a hash symbol with space.
08:24	For now, we will uncomment print(secondVar) and save our script.
08:30	Delete # hash symbol at the beginning of this line.
08:35	Now let’s run the script file.
08:38	In the top right corner of the Source window, click on the Source button.
08:45	Now maximize the Console.
08:50	The line-by-line execution of the script is shown in the Console window.
08:56	The sample vector [1 2 3 4] is printed.
09:02	The values of two variables, 10 and 15 are printed.
09:08	We will clear the Console by clicking on the broom icon.
09:15	Now, we minimize the Console window.
09:19	Now let’s move ahead.
09:23	Suppose, we want to run only a block of code after print(testSample) from the file myfirstscript.R.
09:34	First, select or highlight the block of code, starting from firstVar equals 10 to the end.
09:44	Then in the top right corner of the Source window, click on the Run button with an arrow.
09:53	Now you can see the output of only the highlighted part of the code in the Console window.
10:00	The output shows the values of two variables, 10 and 15 only.
10:07	You can also run a particular block by highlighting it and pressing Ctrl+Enter together.
10:16	We will clear the Console window by clicking on the broom icon.
10:23	Now let us create another R script.
10:28	Use Ctrl+Shift+N to open a new script.
10:33	Save this script in the same folder myProject with the name mysecondscript.
10:43	Now let’s learn how to load myfirstscript.R into mysecondscript.R.
10:53	Go to myfirstscript.R and run it by clicking on the Source button.
11:02	In the Console window, scroll up to locate the source for this script.
11:09	Copy it without the symbol.
11:14	Now let’s get back to our new script mysecondscript.R
11:20	Paste what we have just copied, at the top of the script mysecondscript.R
11:29	We can press Enter after comma for better visibility.
11:35	Next, write one more line to ensure that the execution is from this script only.
11:43	In the Source window, type print and then the following words in parentheses.
11:51	In double quotes, Script space loaded.
11:56	Press Enter.
11:58	Save the script.
12:01	Let us clear the Console again by clicking on the broom icon.
12:09	Now run the script by pressing Ctrl+Shift+Enter together.
12:16	Maximize the Console window.
12:20	You can see the output in the Console window and verify the results.
12:27	Now, we minimize the Console window.
12:30	This brings us to the end of this tutorial. Let us summarize.
12:37	We have learned
12:39	How to create, save and run an R script
12:44	We now suggest an assignment.
12:47	Create a script and save it on Desktop as testscript.R
12:54	Load myfirstscript.R in this script and run it.
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14:00	The Spoken Tutorial project is funded by MHRD, Govt. of India
14:08	The script for this tutorial was contributed by Shaik Sameer (FOSSEE Fellow 2018). This is Sudhakar Kumar from IIT Bombay signing off. Thanks for watching.

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