To change the sign of even number rows in an R data frame column, we can follow the below steps −First of all, create a data frame.Then, use vector multiplication with 1 and minus 1 to change the sign of even number rows.ExampleCreate the data frameLet’s create a data frame as shown below −x

To find the percent of zeros in each row of a data.table object in R, we can follow the below steps −First of all, create a data.table object.Then, use rowSums function along with ncol function to find the percent of zeros in each row of the data.table object.ExampleCreate the data.table objectLet’s create a data.table object as shown below −library(data.table) v1

To find the row standard deviation of columns having same name in R data frame, we can follow the below steps −First of all, create a data frame with some columns having same name.Then, use tapply along with colnames and sd function to find the row standard deviation of columns having same name.ExampleCreate the data frameLet’s create a data frame as shown below −df

To multiply row values in a data frame having multiple rows with single row data frame in R, we can follow the below steps −First of all, create a data frame with multiple rows and a data frame with single row.Then, use mapply function to multiply row values in the data frame having multiple rows with single row data frame.ExampleCreate the first data frameLet’s create a data frame as shown below −x

To find the row standard deviation of columns having same name in data.table object in R, we can follow the below steps −First of all, create a data.table object with some columns having same name.Then, use tapply along with colnames and sd function to find the row standard deviation of columns having same name.ExampleCreate the data.table objectLet’s create a data.table object as shown below −library(data.table) DT

To find the percentage of zeros in each column of a data frame in R, we can follow the below steps −First of all, create a data frame.Then, use colSums function along with nrow function to find the percentage of zeros in each column.Example 1Create the data frameLet’s create a data frame as shown below −x

To multiply corresponding values from two data frames in R, we can follow the below steps −First of all, create two data frames.Then, use mapply function to multiply corresponding values from those two data frames.ExampleCreate the first data frameLet’s create a data frame as shown below −df1

To subset a matrix in R by ignoring a value in one of the columns, we can follow the below steps −First of all, create a matrix.Then, use single square brackets to subset the matrix by ignoring a value in one of the columns.ExampleCreate the matrixLet’s create a matrix as shown below −M

To create a column of first non-zero value in each row of an R data frame, we can follow the below steps −First of all, create a data frame with some zero values.Then, use apply function and a custom function to find the first non-zero in each row of the data frame.ExampleCreate the data frameLet’s create a data frame as shown below −x

To unsplit a split data.table object in R, we can follow the below steps −First of all, create a data.table object.Then, use split function to split the data.table object.After that, use do.call function along with rbind function unsplit the data frame.ExampleCreate the data.table objectLet’s create a data.table object as shown below −library(data.table) Grp