# How to check matrix values equality with a vector values in R?

If we have a vector called V that contains five values and a matrix say M that contains five columns and we want to check whether first value in the vector is present in the first column of each row in the matrix and so on for each value in the vector then we can use the below command −

t(t(M)==V)

## Example 1

Consider the below matrix and vector −

M1<-matrix(rpois(40,1),ncol=2)
M1

The following dataframe is created

   [,1] [,2]
[1,]  2  0
[2,]  0  2
[3,]  1  1
[4,]  0  3
[5,]  2  1
[6,]  2  1
[7,]  2  0
[8,]  0  4
[9,]  0  3
[10,] 1  3
[11,] 0  1
[12,] 4  1
[13,] 1  2
[14,] 1  1
[15,] 2  3
[16,] 3  1
[17,] 3  1
[18,] 0  2
[19,] 0  2
[20,] 0  0

To check whether values in V1 are present in each row of M1 on the above created data frame, add the following code to the above snippet −

M1<-matrix(rpois(40,1),ncol=2)
V1<-c(0,2)
t(t(M1)==V1)

## Output

If you execute all the above given snippets as a single program, it generates the following Output −

       [,1]   [,2]
[1,]  FALSE  FALSE
[2,]   TRUE   TRUE
[3,]  FALSE  FALSE
[4,]   TRUE  FALSE
[5,]  FALSE  FALSE
[6,]  FALSE  FALSE
[7,]  FALSE  FALSE
[8,]   TRUE  FALSE
[9,]   TRUE  FALSE
[10,] FALSE  FALSE
[11,]  TRUE  FALSE
[12,] FALSE  FALSE
[13,] FALSE   TRUE
[14,] FALSE  FALSE
[15,] FALSE  FALSE
[16,] FALSE  FALSE
[17,] FALSE  FALSE
[18,]  TRUE   TRUE
[19,]  TRUE   TRUE
[20,] TRUE   FALSE

## Example 2

Consider the below matrix and vector −

M2<-matrix(round(rnorm(40),1),ncol=2)
M2

The following dataframe is created

     [,1]  [,2]
[1,]   1.6 -0.8
[2,]   0.7 -0.7
[3,]   0.1 -1.1
[4,]   0.1  1.5
[5,]   0.9  0.3
[6,]   1.3  1.2
[7,]   0.7 -0.3
[8,]  -0.8 -0.1
[9,]  -0.5 -1.4
[10,] -0.3  1.0
[11,]  0.6 -1.3
[12,] -0.4  0.8
[13,]  0.0  0.8
[14,]  1.5  0.5
[15,] -0.3 -0.8
[16,]  1.0 -0.5
[17,]  1.9 -1.3
[18,]  1.7 -0.7
[19,]  2.7  0.4
[20,]  0.9 -0.5

To check whether values in V2 are present in each row of M2 on the above created data frame, add the following code to the above snippet −

M2<-matrix(round(rnorm(40),1),ncol=2)
V2<-c(0.1,0.5)
t(t(M2)==V2)

## Output

If you execute all the above given snippets as a single program, it generates the following Output −

       [,1]   [,2]
[1,]  FALSE  FALSE
[2,]  FALSE  FALSE
[3,]  TRUE   FALSE
[4,]  TRUE   FALSE
[5,]  FALSE  FALSE
[6,]  FALSE  FALSE
[7,]  FALSE  FALSE
[8,]  FALSE  FALSE
[9,]  FALSE  FALSE
[10,] FALSE  FALSE
[11,] FALSE  FALSE
[12,] FALSE  FALSE
[13,] FALSE  FALSE
[14,] FALSE   TRUE
[15,] FALSE  FALSE
[16,] FALSE  FALSE
[17,] FALSE  FALSE
[18,] FALSE  FALSE
[19,] FALSE  FALSE
[20,] FALSE  FALSE

Updated on: 01-Nov-2021

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