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#The hash symbols denote comments. They aren't the part of the commands.

#To create the following matrix

# 1 4 7

# 4 7 8

# 6 6 9

matrix(c(1,4,6,4,7,6,7,8,9),3,3)

#By default the values are taken column wise.

#3,3 represents the number of rows and columns

#respectively.

#However only either row or column may be specified.

#In that case, the other will be automatically adjusted.

#so, alternative

matrix(c(1,4,6,4,7,6,7,8,9),3)

#or. If we leave row unspecified, then there needs a comma

#before column number

matrix(c(1,4,6,4,7,6,7,8,9),,3)

#If we want to arrange values row wise

matrix(1:9,,3,byrow=T)

#or in short

matrix(1:9,,3,T)

#By default, it would be

matrix(1:9,3)

#generating 700000 observations from uniform distribution

#in 7 columns

matrix(runif(700000),,7)

#examples: execute to visualize!

matrix(c(1:19,23),,4)

#if there inadequate values, then values would be recycled

#but with a warning.

matrix(c(17,19,20,22,25),3)

#Let's call our initial matrix y and add 1 to all

elements.

y+1

#see [2,3]th element of y where 2 is for row and 3 for

#column

y[2,3]

#all columns of 1st row

y[1,]

#all rows of 2nd column

y[,2]

#Replacing elements e.g, to make all column values of 2nd

#row 10.

y[2,]=10

#Replace 1st three elements of 3rd column by 1, 3 & 4

respectively

y[1:3,3]=c(1,3,4)

#make a matrix having elements 1 in 10 rows and 5 columns

matrix(rep(1,50),10)

#or in short

matrix(1,10,5)

#in the above short code, both row and column number must

#be mentioned.

#A diagonal matrix of order 4

diag(4)

#or of order 5

diag(5)

#Diagnal elements specified

diag(1:5)

#Matrix with diagonal elements 1,3 & 6

diag(c(1,3,6))

#Suppose x is a matrix. to make vector off its diagonal #elements

x=matrix(9:17,3)

diag(x)

#to make a new matrix using diagonal elements of another #matrix, just give above command a name, say, y.

y=diag(x)

#To make a diagonal matrix using diagonal elements of #another matrix.

z=diag(diag(x))

#The hash symbols denote comments. They aren't the part of the commands.

#To create the following matrix

# 1 4 7

# 4 7 8

# 6 6 9

matrix(c(1,4,6,4,7,6,7,8,9),3,3)

#By default the values are taken column wise.

#3,3 represents the number of rows and columns

#respectively.

#However only either row or column may be specified.

#In that case, the other will be automatically adjusted.

#so, alternative

matrix(c(1,4,6,4,7,6,7,8,9),3)

#or. If we leave row unspecified, then there needs a comma

#before column number

matrix(c(1,4,6,4,7,6,7,8,9),,3)

#If we want to arrange values row wise

matrix(1:9,,3,byrow=T)

#or in short

matrix(1:9,,3,T)

#By default, it would be

matrix(1:9,3)

#generating 700000 observations from uniform distribution

#in 7 columns

matrix(runif(700000),,7)

#examples: execute to visualize!

matrix(c(1:19,23),,4)

#if there inadequate values, then values would be recycled

#but with a warning.

matrix(c(17,19,20,22,25),3)

#Let's call our initial matrix y and add 1 to all

elements.

y+1

#see [2,3]th element of y where 2 is for row and 3 for

#column

y[2,3]

#all columns of 1st row

y[1,]

#all rows of 2nd column

y[,2]

#Replacing elements e.g, to make all column values of 2nd

#row 10.

y[2,]=10

#Replace 1st three elements of 3rd column by 1, 3 & 4

respectively

y[1:3,3]=c(1,3,4)

#make a matrix having elements 1 in 10 rows and 5 columns

matrix(rep(1,50),10)

#or in short

matrix(1,10,5)

#in the above short code, both row and column number must

#be mentioned.

#A diagonal matrix of order 4

diag(4)

#or of order 5

diag(5)

#Diagnal elements specified

diag(1:5)

#Matrix with diagonal elements 1,3 & 6

diag(c(1,3,6))

#Suppose x is a matrix. to make vector off its diagonal #elements

x=matrix(9:17,3)

diag(x)

#to make a new matrix using diagonal elements of another #matrix, just give above command a name, say, y.

y=diag(x)

#To make a diagonal matrix using diagonal elements of #another matrix.

z=diag(diag(x))

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