Difference between revisions of "R/C2/Creating-Matrices-using-Data-Frames/English"
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'''Author''': Shaik Sameer (IIIT Vadodara) and Sudhakar Kumar (IIT Bombay) | '''Author''': Shaik Sameer (IIIT Vadodara) and Sudhakar Kumar (IIT Bombay) | ||
| − | '''Keywords''': R, RStudio, matrices, data frames, video tutorial. | + | '''Keywords''': R, RStudio, matrices, data frames, transpose, determinant, video tutorial. |
| − | + | ||
{| border =1 | {| border =1 | ||
| Line 13: | Line 12: | ||
Opening slide | Opening slide | ||
| − | ||Welcome to the spoken tutorial | + | || Welcome to the spoken tutorial on '''Creating Matrices using Data Frames.''' |
| − | |- | + | |- |
|| Show slide | || Show slide | ||
| Line 23: | Line 22: | ||
* Perform basic operations on '''matrices''' | * Perform basic operations on '''matrices''' | ||
| − | + | |- | |
| − | |- | + | |
|| Show slide | || Show slide | ||
| Line 30: | Line 28: | ||
spoken-tutorial.org | spoken-tutorial.org | ||
| − | || To understand this tutorial, you should know* '''Data frames '''and '''Vectors''' in '''R''' | + | || To understand this tutorial, you should know, |
| − | * | + | * '''Data frames''' and '''Vectors''' in '''R''' |
| + | * '''Basics''' of '''Matrices''' | ||
* '''R script''' in '''RStudio''' | * '''R script''' in '''RStudio''' | ||
| − | * How to set '''working directory''' in''' RStudio''' | + | * How to set '''working directory''' in '''RStudio''' |
| − | + | ||
| − | + | ||
If not, please locate the relevant tutorials on '''R''' on this website. | If not, please locate the relevant tutorials on '''R''' on this website. | ||
| − | |- | + | |- |
|| Show slide | || Show slide | ||
System Specifications | System Specifications | ||
| − | + | || This tutorial is recorded on | |
| − | + | * '''Ubuntu Linux '''OS version''' 16.04''' | |
| − | || This tutorial is recorded on* '''Ubuntu Linux '''OS version''' 16.04''' | + | |
* '''R '''version''' 3.4.4''' | * '''R '''version''' 3.4.4''' | ||
* '''RStudio''' version''' 1.1.456''' | * '''RStudio''' version''' 1.1.456''' | ||
| − | |||
| − | |||
Install '''R''' version '''3.2.0''' or higher. | Install '''R''' version '''3.2.0''' or higher. | ||
| − | |- | + | |- |
|| Show slide | || Show slide | ||
Download Files | Download Files | ||
| − | || For this tutorial, we will use the '''data frame CaptaincyData.csv '''and a '''script '''file '''myMatrix.R'''. | + | ||For this tutorial, we will use the '''data frame CaptaincyData.csv''' and a '''script '''file '''myMatrix.R'''. |
| − | + | ||
Please download these files from the '''Code files''' link of this tutorial. | Please download these files from the '''Code files''' link of this tutorial. | ||
| − | |- | + | |- |
|| [Computer screen] | || [Computer screen] | ||
Highlight '''CaptaincyData.csv '''and '''myMatrix.R''' in the folder '''Matrices ''' | Highlight '''CaptaincyData.csv '''and '''myMatrix.R''' in the folder '''Matrices ''' | ||
|| I have downloaded and moved these files to '''Matrices''' folder in '''myProject''' folder on the '''Desktop'''. | || I have downloaded and moved these files to '''Matrices''' folder in '''myProject''' folder on the '''Desktop'''. | ||
| − | |||
I have also set '''Matrices''' folder as my '''Working Directory.''' | I have also set '''Matrices''' folder as my '''Working Directory.''' | ||
| − | |- | + | |- |
|| | || | ||
| − | || Let us switch to | + | || Let us switch to '''RStudio'''. |
| − | |- | + | |- |
|| Click '''myMatrix.R''' in '''RStudio''' | || Click '''myMatrix.R''' in '''RStudio''' | ||
| − | |||
Point to''' myMatrix.R''' in '''Rstudio.''' | Point to''' myMatrix.R''' in '''Rstudio.''' | ||
| − | || Open the '''script myMatrix.R''' in '''RStudio | + | || Open the '''script myMatrix.R''' in '''RStudio'''. |
For this, click on the '''script myMatrix.R''' | For this, click on the '''script myMatrix.R''' | ||
| − | + | '''Script myMatrix.R''' opens in '''RStudio'''. | |
| − | '''Script myMatrix.R '''opens in''' RStudio | + | |
|- | |- | ||
| − | || Highlight '''rm '''in '''Source '''window | + | || Highlight '''rm''' in '''Source '''window |
| − | || Here, I have used '''rm ''' | + | || Here, I have used '''rm function''' to remove all existing variables from memory. |
| − | + | ||
This prevents errors such as use of older data. | This prevents errors such as use of older data. | ||
| − | |- | + | |- |
|| Highlight '''Source''' button | || Highlight '''Source''' button | ||
| − | |||
Highlight '''captaincy''' in the '''Source''' window | Highlight '''captaincy''' in the '''Source''' window | ||
|| Run this '''script''' by clicking on the '''Source '''button. | || Run this '''script''' by clicking on the '''Source '''button. | ||
| − | + | The captaincy '''data frame''' is displayed in the '''Source''' window. | |
| − | The captaincy '''data frame''' is displayed in the '''Source '''window. | + | |- |
| − | |- | + | |
|| Show slide | || Show slide | ||
Data in Matrix Format | Data in Matrix Format | ||
|| We need our data in a '''matrix''' form to: | || We need our data in a '''matrix''' form to: | ||
| − | * Calculate the inverse of a''' matrix''' | + | * Calculate the inverse of a '''matrix''' |
| − | * Perform matrix operations like addition, subtraction, multiplication, etc. | + | * Perform '''matrix''' operations like addition, subtraction, multiplication, etc. |
| − | + | Hence, we need to learn how to convert a '''data frame''' into a '''matrix'''. | |
| − | + | |- | |
| − | Hence, we need to learn how to convert a''' data frame''' into a '''matrix'''. | + | |
| − | |- | + | |
|| | || | ||
|| Let us get back to '''RStudio'''. | || Let us get back to '''RStudio'''. | ||
| − | |- | + | |- |
|| [RStudio] | || [RStudio] | ||
| − | |||
Highlight the three rows of '''captaincy''' | Highlight the three rows of '''captaincy''' | ||
| − | |||
| − | |||
|| We will convert the values in first three rows of '''played''', '''won''' and '''lost''' columns into a '''matrix'''. | || We will convert the values in first three rows of '''played''', '''won''' and '''lost''' columns into a '''matrix'''. | ||
| − | We will create a '''subset '''for extracting these values. | + | We will create a '''subset''' for extracting these values. |
| − | |- | + | |- |
| + | || Highlight '''myMatrix.R '''in the '''Source''' window | ||
| + | || Click on the '''script myMatrix.R''' | ||
| + | |- | ||
|| [RStudio] | || [RStudio] | ||
| − | |||
| − | |||
'''subdata <- captaincy[1:3, c("played", "won", "lost")]''' | '''subdata <- captaincy[1:3, c("played", "won", "lost")]''' | ||
| + | || In the '''Source '''window, type the following command Press '''Enter'''. | ||
| + | I am resizing the '''Source''' window. | ||
| − | + | Press '''Enter''' to go to the next line. | |
Press '''Enter''' at the end of every command. | Press '''Enter''' at the end of every command. | ||
| − | |- | + | |- |
|| [RStudio] | || [RStudio] | ||
| − | Highlight''' 1:3 '''in the '''Source '''window | + | Highlight '''1:3''' in the '''Source '''window |
Highlight '''c''' in the '''Source '''window | Highlight '''c''' in the '''Source '''window | ||
|| '''1 colon 3''' indicates that the first three rows are to be extracted. | || '''1 colon 3''' indicates that the first three rows are to be extracted. | ||
| − | '''c''' is the concatenate vector command with names of each column within double quotes. | + | '''c''' is the '''concatenate vector command''' with names of each column within double quotes. |
| − | |- | + | |- |
|| Press '''Ctrl + S''' >> Press '''Ctrl+Enter''' keys. | || Press '''Ctrl + S''' >> Press '''Ctrl+Enter''' keys. | ||
|| Save the '''script''' and execute the current line. | || Save the '''script''' and execute the current line. | ||
| − | |- | + | |- |
|| [RStudio] | || [RStudio] | ||
| − | + | Highlight '''subData '''in the '''Environment''' window. | |
| − | Highlight '''subData '''in the '''Environment '''window. | + | |
| − | + | ||
Click on the arrow before '''subData'''. | Click on the arrow before '''subData'''. | ||
| Line 156: | Line 139: | ||
Click on the arrow before '''subData''' to expand its contents. | Click on the arrow before '''subData''' to expand its contents. | ||
| − | |- | + | |- |
|| | || | ||
|| Now, we will convert this '''subset''' into a '''matrix'''. | || Now, we will convert this '''subset''' into a '''matrix'''. | ||
| − | |- | + | |- |
|| [RStudio] | || [RStudio] | ||
| − | |||
'''matrixA <- as.matrix(subdata)''' | '''matrixA <- as.matrix(subdata)''' | ||
| − | || In the '''Source '''window, type '''matrixA '''then press '''Alt '''and ''' | + | || In the '''Source''' window, type '''matrixA''' then press '''Alt''' and '''hyphen'''(-)keys simultaneously. |
| − | + | Now type '''as'''dot '''matrix''', within parentheses type '''subdata''' and press '''Enter'''. | |
| − | Now type '''as '''dot '''matrix''', within parentheses type '''subdata '''and press '''Enter'''. | + | |- |
| − | |- | + | || Highlight '''as.matrix''' in the '''Source''' window |
| − | || Highlight '''as.matrix''' in the '''Source '''window | + | || '''as.matrix function''' is used to convert the '''subdata '''into a '''matrix'''. |
| − | || '''as.matrix''' | + | |- |
| − | |- | + | |
|| [RStudio] | || [RStudio] | ||
'''print(matrixA) ''' | '''print(matrixA) ''' | ||
| − | + | || In '''Source''' window, type '''print''', within '''parentheses''' '''matrixA'''. | |
| − | + | |- | |
| − | Press '''Ctrl + S''' >> Highlight two lines >> Press '''Ctrl+Enter''' keys. | + | || Press '''Ctrl + S''' >> Highlight two lines >> Press '''Ctrl+Enter''' keys. |
| − | || | + | || Save the '''script''' and run these two lines. |
| − | + | |- | |
| − | + | ||
| − | Save the '''script''' and run these two lines. | + | |
| − | |- | + | |
|| Highlight the output in the '''Console''' window | || Highlight the output in the '''Console''' window | ||
|| The content of '''matrixA''' is shown on the '''Console''' window. | || The content of '''matrixA''' is shown on the '''Console''' window. | ||
| − | + | |- | |
| − | + | ||
| − | + | ||
| − | |- | + | |
|| cursor on the interface. | || cursor on the interface. | ||
|| Now let us create a 3 by 3 '''identity matrix'''. | || Now let us create a 3 by 3 '''identity matrix'''. | ||
| − | Create a '''vector '''named '''values''' containing the row wise values of a 3 by 3 identity matrix. | + | Create a '''vector''' named '''values''' containing the row-wise values of a 3 by 3 identity matrix. |
| − | |- | + | |- |
|| [RStudio] | || [RStudio] | ||
'''values <- c(1,0,0,0,1,0,0,0,1)''' | '''values <- c(1,0,0,0,1,0,0,0,1)''' | ||
|| In the '''Source''' window, type the following command and press '''Enter'''. | || In the '''Source''' window, type the following command and press '''Enter'''. | ||
| − | |- | + | |- |
|| [RStudio] | || [RStudio] | ||
| − | |||
'''matrixB <- matrix(values, nrow = 3, ncol = 3, byrow = TRUE)''' | '''matrixB <- matrix(values, nrow = 3, ncol = 3, byrow = TRUE)''' | ||
| − | || Now we will create a variable '''matrixB''' to store the '''matrix''' created using vector | + | || Now we will create a variable '''matrixB''' to store the '''matrix''' created using vector values. |
| − | In the '''Source '''window, type the following command | + | In the '''Source''' window, type the following command. Press '''Enter'''. |
| − | |- | + | |
| + | Press '''Enter''' to go to the next line. | ||
| + | |- | ||
|| [RStudio] | || [RStudio] | ||
| Line 214: | Line 190: | ||
Highlight '''byrow''' in the '''Source''' window | Highlight '''byrow''' in the '''Source''' window | ||
| − | || Here, I have used '''matrix''' | + | || Here, I have used '''matrix function''' with following '''arguments''': |
| − | * number of rows as ''' | + | * data of '''values''' vector |
| − | * number of columns as '''ncol '''equal to''' 3''' | + | * number of rows as '''nrow''' equal to '''3''' |
| − | * '''byrow '''equal to''' TRUE''' indicates that, data provided has to be arranged row-wise in the matrix. | + | * number of columns as '''ncol''' equal to ''' 3''' |
| + | * '''byrow '''equal to''' TRUE''' indicates that, data provided has to be arranged row-wise in the '''matrix'''. | ||
| − | + | |- | |
| − | |- | + | |
|| [RStudio] | || [RStudio] | ||
'''print(matrixB)''' | '''print(matrixB)''' | ||
| − | || Now, type '''print ''' | + | || Now, type '''print''' within parentheses type '''matrixB''' to show the contents of the '''matrix'''. |
| − | |- | + | |- |
|| Press''' Ctrl + S''' keys >> Highlight three lines >> Press '''Ctrl + Enter''' keys | || Press''' Ctrl + S''' keys >> Highlight three lines >> Press '''Ctrl + Enter''' keys | ||
| − | || Save the '''script''' and run the last three lines | + | || Save the '''script''' and run the last three lines of code. |
| − | |- | + | |- |
|| Highlight the output in the '''Console''' window | || Highlight the output in the '''Console''' window | ||
| − | || The '''identity | + | || The '''identity matrix''' is shown on the '''Console''' window. |
| − | |- | + | |- |
|| Cursor on the interface. | || Cursor on the interface. | ||
|| Now let us perform some arithmetic operations on '''matrices'''. | || Now let us perform some arithmetic operations on '''matrices'''. | ||
| − | |- | + | |- |
| + | || Highlight the boundary of '''Source''' window | ||
| + | || I will resize the '''Source''' window. | ||
| + | |- | ||
|| [RStudio] | || [RStudio] | ||
| Line 240: | Line 219: | ||
'''matrixA - matrixB ''' | '''matrixA - matrixB ''' | ||
| − | || We will add and subtract '''matrices | + | || We will add and subtract '''matrices A''' and '''B'''. |
| − | + | In the '''Source''' window, type '''matrixA''' space '''plus''' sign space '''matrixB'''. | |
| − | Next, type '''matrixA '''space''' minus '''sign'' | + | Next, type '''matrixA''' space '''minus''' sign space ''' ''matrixB''' |
| − | |- | + | |- |
|| Press '''Ctrl + S''' >> Press '''Ctrl+Enter''' keys. | || Press '''Ctrl + S''' >> Press '''Ctrl+Enter''' keys. | ||
| Line 251: | Line 230: | ||
|| Save the '''script''' and run these two lines. | || Save the '''script''' and run these two lines. | ||
| − | The resulting matrices are shown on the '''Console''' window. | + | I will resize the '''Console''' window to see the output properly. |
| − | |- | + | |
| + | The resulting '''matrices''' are shown on the '''Console''' window. | ||
| + | |- | ||
|| [RStudio] | || [RStudio] | ||
'''matrixA * matrixB ''' | '''matrixA * matrixB ''' | ||
| − | || Let us perform multiplication of individual elements of two '''matrices'''. | + | || Let us perform multiplication of individual '''elements''' of two '''matrices'''. |
| − | + | In the '''Source''' window, type '''matrixA''' space '''asterisk''' sign space '''matrixB''' | |
| − | |- | + | |- |
| − | || Press '''Ctrl + S''' >> Press '''Ctrl+Enter''' keys. | + | || Press '''Ctrl + S''' >> Press '''Ctrl + Enter''' keys. |
| − | Highlight the output on the '''Console''' window | + | Highlight the output on the '''Console''' window. |
| − | || Save the '''script''' and run | + | || Save the '''script''' and run the current lines. |
| − | The resulting | + | The resulting '''matrix''' is shown on the '''Console''' window. |
| − | |- | + | |- |
|| Highlight '''matrixA''' and '''matrixB''' in '''Environment''' window | || Highlight '''matrixA''' and '''matrixB''' in '''Environment''' window | ||
|| Now, we will perform a true '''matrix''' multiplication with these '''matrices'''. | || Now, we will perform a true '''matrix''' multiplication with these '''matrices'''. | ||
| Line 272: | Line 253: | ||
1st row of '''matrixA''' is multiplied by 1st column of '''matrixB'''. | 1st row of '''matrixA''' is multiplied by 1st column of '''matrixB'''. | ||
| − | Hence number of columns of '''matrixA''' should be equal to number of rows of '''matrixB'''. | + | Hence number of columns of '''matrixA''' should be equal to the number of rows of '''matrixB'''. |
| − | |- | + | |- |
|| '''matrixA %*% matrixB ''' | || '''matrixA %*% matrixB ''' | ||
| − | || In the '''Source''' window, | + | || In the '''Source''' window, type '''matrixA''' space '''percentage''' sign '''asterisk percentage''' sign space '''matrixB'''. |
| − | + | |- | |
| − | type '''matrixA '''space''' percentage '''sign''' asterisk percentage '''sign | + | |
| − | |- | + | |
|| Press '''Ctrl + S''' >> Press '''Ctrl+Enter''' keys. | || Press '''Ctrl + S''' >> Press '''Ctrl+Enter''' keys. | ||
Highlight the output on the '''Console''' window. | Highlight the output on the '''Console''' window. | ||
| − | || Save the '''script''' and run | + | || Save the '''script''' and run the current line. |
| − | The resulting | + | The resulting '''matrix''' is shown on the '''Console''' window. |
| − | |- | + | |- |
|| Cursor on the interface. | || Cursor on the interface. | ||
|| Now let us calculate the '''transpose''' and '''determinant''' of '''matrixA'''. | || Now let us calculate the '''transpose''' and '''determinant''' of '''matrixA'''. | ||
| − | |- | + | |- |
|| [RStudio]'''t(matrixA)''' | || [RStudio]'''t(matrixA)''' | ||
'''det(matrixA)''' | '''det(matrixA)''' | ||
| − | || In the '''Source''' window, type''' t '''and '''matrixA '''in parentheses | + | || In the '''Source''' window, type '''t''' and '''matrixA''' in parentheses. |
| − | + | Now, type '''det''' and '''matrixA''' in parentheses. | |
| − | |- | + | |- |
|| Press '''Ctrl + S''' >> Press '''Ctrl+Enter''' keys. | || Press '''Ctrl + S''' >> Press '''Ctrl+Enter''' keys. | ||
| Line 301: | Line 280: | ||
|| Save the '''script''' and run these two lines. | || Save the '''script''' and run these two lines. | ||
| − | The corresponding output is shown on the '''Console''' | + | The corresponding output is shown on the '''Console''' window. |
| − | |- | + | |- |
|| | || | ||
|| Let us summarize what we have learnt. | || Let us summarize what we have learnt. | ||
| − | |- | + | |- |
|| Show slide | || Show slide | ||
Summary | Summary | ||
| − | + | || In this tutorial, we have learnt how to: | |
| − | + | * Convert a '''data frame''' into a '''matrix''' | |
| − | + | ||
| − | + | ||
| − | + | ||
| − | || In this tutorial, we have learnt how to: * Convert a '''data frame''' into a '''matrix''' | + | |
* Create a '''matrix''' in '''R''' | * Create a '''matrix''' in '''R''' | ||
* Perform basic operations on '''matrices''' | * Perform basic operations on '''matrices''' | ||
| − | + | |- | |
| − | |- | + | |
|| Show slide | || Show slide | ||
Assignment | Assignment | ||
| + | || We now suggest an assignment. | ||
| + | * Consider 2 '''vectors''' c(9,10,11,12) and c(13,14,15,16). | ||
| + | * Create a 4 by 2 '''matrix''' from these two '''vectors'''. | ||
| − | + | For solution, please refer to the '''Additional materials''' section on this website. | |
| − | + | |- | |
| − | + | ||
| − | + | ||
| − | + | ||
| − | + | ||
| − | + | ||
| − | |- | + | |
|| Show slide | || Show slide | ||
| Line 339: | Line 310: | ||
Please download and watch it. | Please download and watch it. | ||
| − | |- | + | |- |
|| Show slide | || Show slide | ||
| Line 346: | Line 317: | ||
Please contact us. | Please contact us. | ||
| − | |- | + | |- |
|| Show Slide | || Show Slide | ||
Forum to answer questions | Forum to answer questions | ||
|| Please post your timed queries in this forum. | || Please post your timed queries in this forum. | ||
| − | |- | + | |- |
|| Show Slide | || Show Slide | ||
Forum to answer questions | Forum to answer questions | ||
|| Please post your general queries in this forum. | || Please post your general queries in this forum. | ||
| − | |- | + | |- |
|| Show Slide | || Show Slide | ||
Textbook Companion | Textbook Companion | ||
| − | ||The '''FOSSEE '''team coordinates the '''TBC ''' project. | + | || The '''FOSSEE ''' team coordinates the '''TBC '''project. |
For more details, please visit these sites. | For more details, please visit these sites. | ||
| − | |- | + | |- |
|| Show Slide | || Show Slide | ||
Acknowledgement | Acknowledgement | ||
|| The Spoken Tutorial project is funded by NMEICT, MHRD, Govt. of India | || The Spoken Tutorial project is funded by NMEICT, MHRD, Govt. of India | ||
| − | |- | + | |- |
|| Show Slide | || Show Slide | ||
Thank You | Thank You | ||
|| The script for this tutorial was contributed by Shaik Sameer (FOSSEE Fellow 2018). | || 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. | This is Sudhakar Kumar from IIT Bombay signing off. Thanks for watching. | ||
|- | |- | ||
|} | |} | ||
Latest revision as of 21:55, 5 March 2019
Title of script: Creating Matrices using Data Frames
Author: Shaik Sameer (IIIT Vadodara) and Sudhakar Kumar (IIT Bombay)
Keywords: R, RStudio, matrices, data frames, transpose, determinant, video tutorial.
| Visual Cue | Narration |
| Show slide
Opening slide |
Welcome to the spoken tutorial on Creating Matrices using Data Frames. |
| Show slide
Learning Objectives |
In this tutorial, we will learn how to:
|
| Show slide
Pre-requisites spoken-tutorial.org |
To understand this tutorial, you should know,
If not, please locate the relevant tutorials on R on this website. |
| Show slide
System Specifications |
This tutorial is recorded on
Install R version 3.2.0 or higher. |
| Show slide
Download Files |
For this tutorial, we will use the data frame CaptaincyData.csv and a script file myMatrix.R.
Please download these files from the Code files link of this tutorial. |
| [Computer screen]
Highlight CaptaincyData.csv and myMatrix.R in the folder Matrices |
I have downloaded and moved these files to Matrices folder in myProject folder on the Desktop.
I have also set Matrices folder as my Working Directory. |
| Let us switch to RStudio. | |
| Click myMatrix.R in RStudio
Point to myMatrix.R in Rstudio. |
Open the script myMatrix.R in RStudio.
For this, click on the script myMatrix.R Script myMatrix.R opens in RStudio. |
| Highlight rm in Source window | Here, I have used rm function to remove all existing variables from memory.
This prevents errors such as use of older data. |
| Highlight Source button
Highlight captaincy in the Source window |
Run this script by clicking on the Source button.
The captaincy data frame is displayed in the Source window. |
| Show slide
Data in Matrix Format |
We need our data in a matrix form to:
Hence, we need to learn how to convert a data frame into a matrix. |
| Let us get back to RStudio. | |
| [RStudio]
Highlight the three rows of captaincy |
We will convert the values in first three rows of played, won and lost columns into a matrix.
We will create a subset for extracting these values. |
| Highlight myMatrix.R in the Source window | Click on the script myMatrix.R |
| [RStudio]
subdata <- captaincy[1:3, c("played", "won", "lost")] |
In the Source window, type the following command Press Enter.
I am resizing the Source window. Press Enter to go to the next line. Press Enter at the end of every command. |
| [RStudio]
Highlight 1:3 in the Source window Highlight c in the Source window |
1 colon 3 indicates that the first three rows are to be extracted.
c is the concatenate vector command with names of each column within double quotes. |
| Press Ctrl + S >> Press Ctrl+Enter keys. | Save the script and execute the current line. |
| [RStudio]
Highlight subData in the Environment window. Click on the arrow before subData. |
The variable subData appears in the Environment window.
Click on the arrow before subData to expand its contents. |
| Now, we will convert this subset into a matrix. | |
| [RStudio]
matrixA <- as.matrix(subdata) |
In the Source window, type matrixA then press Alt and hyphen(-)keys simultaneously.
Now type asdot matrix, within parentheses type subdata and press Enter. |
| Highlight as.matrix in the Source window | as.matrix function is used to convert the subdata into a matrix. |
| [RStudio]
print(matrixA) |
In Source window, type print, within parentheses matrixA. |
| Press Ctrl + S >> Highlight two lines >> Press Ctrl+Enter keys. | Save the script and run these two lines. |
| Highlight the output in the Console window | The content of matrixA is shown on the Console window. |
| cursor on the interface. | Now let us create a 3 by 3 identity matrix.
Create a vector named values containing the row-wise values of a 3 by 3 identity matrix. |
| [RStudio]
values <- c(1,0,0,0,1,0,0,0,1) |
In the Source window, type the following command and press Enter. |
| [RStudio]
matrixB <- matrix(values, nrow = 3, ncol = 3, byrow = TRUE) |
Now we will create a variable matrixB to store the matrix created using vector values.
In the Source window, type the following command. Press Enter. Press Enter to go to the next line. |
| [RStudio]
Highlight values in the Source window Highlight nrow and ncol in the Source window Highlight byrow in the Source window |
Here, I have used matrix function with following arguments:
|
| [RStudio]
print(matrixB) |
Now, type print within parentheses type matrixB to show the contents of the matrix. |
| Press Ctrl + S keys >> Highlight three lines >> Press Ctrl + Enter keys | Save the script and run the last three lines of code. |
| Highlight the output in the Console window | The identity matrix is shown on the Console window. |
| Cursor on the interface. | Now let us perform some arithmetic operations on matrices. |
| Highlight the boundary of Source window | I will resize the Source window. |
| [RStudio]
matrixA + matrixB matrixA - matrixB |
We will add and subtract matrices A and B.
In the Source window, type matrixA space plus sign space matrixB. Next, type matrixA space minus sign space matrixB |
| Press Ctrl + S >> Press Ctrl+Enter keys.
Highlight the output on the Console window |
Save the script and run these two lines.
I will resize the Console window to see the output properly. The resulting matrices are shown on the Console window. |
| [RStudio]
matrixA * matrixB |
Let us perform multiplication of individual elements of two matrices.
In the Source window, type matrixA space asterisk sign space matrixB |
| Press Ctrl + S >> Press Ctrl + Enter keys.
Highlight the output on the Console window. |
Save the script and run the current lines.
The resulting matrix is shown on the Console window. |
| Highlight matrixA and matrixB in Environment window | Now, we will perform a true matrix multiplication with these matrices.
1st row of matrixA is multiplied by 1st column of matrixB. Hence number of columns of matrixA should be equal to the number of rows of matrixB. |
| matrixA %*% matrixB | In the Source window, type matrixA space percentage sign asterisk percentage sign space matrixB. |
| Press Ctrl + S >> Press Ctrl+Enter keys.
Highlight the output on the Console window. |
Save the script and run the current line.
The resulting matrix is shown on the Console window. |
| Cursor on the interface. | Now let us calculate the transpose and determinant of matrixA. |
| [RStudio]t(matrixA)
det(matrixA) |
In the Source window, type t and matrixA in parentheses.
Now, type det and matrixA in parentheses. |
| Press Ctrl + S >> Press Ctrl+Enter keys.
Highlight the output on the Console window. |
Save the script and run these two lines.
The corresponding output is shown on the Console window. |
| Let us summarize what we have learnt. | |
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Summary |
In this tutorial, we have learnt how to:
|
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Assignment |
We now suggest an assignment.
For solution, please refer to the Additional materials section on this website. |
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About the Spoken Tutorial Project |
The video at the following link summarises the Spoken Tutorial project.
Please download and watch it. |
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Spoken Tutorial Workshops |
We conduct workshops using Spoken Tutorials and give certificates.
Please contact us. |
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Forum to answer questions |
Please post your timed queries in this forum. |
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Forum to answer questions |
Please post your general queries in this forum. |
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Textbook Companion |
The FOSSEE team coordinates the TBC project.
For more details, please visit these sites. |
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Acknowledgement |
The Spoken Tutorial project is funded by NMEICT, MHRD, Govt. of India |
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Thank You |
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. |
