To round each value in columns if some columns are categorical in R data frame, we can follow the below steps −First of all, create a data frame.Then, use numcolwise function from plyr package to round each value in columns if some columns are categorical.ExampleCreate the data frameLet’s create a data frame as shown below −Level

To change the color of a particular bar using geom_bar in R, we can provide the count corresponding to the value for which we want to change the color inside aes function.For Example, if we have a data frame called df that contains two columns say V and F where V is categorical and F is for frequency and we want to change the color of frequency 10 in bar plot then we can use the below mentioned command −ggplot(df, aes(V, F))+geom_bar(aes(fill=..F..==10), stat="identity")ExampleFollowing snippet creates a sample data frame −xRead More

To find the log2 of each value if some columns are categorical in R data frame, we can follow the below steps −First of all, create a data frame.Then, use numcolwise function from plyr package to find the log2 if some columns are categorical.ExampleCreate the data frameLet’s create a data frame as shown below −Level

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

To remove rows in data.table object in R that contains a specific number, we can follow the below steps −First of all, create a data.table object.Then, use single square subsetting with apply function to remove rows that contains a specific number.ExampleCreate the data.table objectLet’s create a data.table object as shown below: −library(data.table) x

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

To add a value to a particular matrix element in R, we can use subsetting for the particular value with single square brackets.For Example, if we have a matrix called M and we want to add 10 to the fifth value in second column then can use the below mentioned command −M[5,2]

To multiply row values in a matrix having multiple rows with single row matrix in R, we can follow the below steps −First of all, create a matrix with multiple rows and a matrix with single row.Then, use mapply function to multiply row values in those matrices.ExampleCreate the first matrixLet’s create a matrix as shown below −M1

To subset a data.table object in R by ignoring a value in one of the columns, we can follow the below steps −First of all, create a data.table object.Then, use single square brackets to subset the data.table object by ignoring a value in one of the columns.ExampleCreate the data.table objectLet’s create a data.table object as shown below −library(data.table) x

To find the percentage of each category in a data.table object in R, we can follow the below steps −First of all, create a data.table object.Then, use summarise function of dplyr package after grouping along with n and nrow.ExampleCreate the data.table objectLet’s create a data.table object as shown below −library(data.table) Factor