To display text in bar plot in the middle using ggplot2 in R, we can follow the below steps −First of all, create a data frame.Then, use ggplot function and geom_bar function to create the bar plot along with geom_text function to display the text in the middleExampleCreate the data frameLet’s create a data frame as shown below −x

To find the percentage of zeros in each column of a data.table object in R, we can follow the below steps −First of all, create a data.table object.Then, use colSums function along with nrow function to find the percentage of zeros in each column.Example 1Create the data.table objectLet’s create a data.table object as shown below −library(data.table) y1

To remove rows in R matrix that contains a specific number, we can follow the below steps −First of all, create a matrix.Then, use single square subsetting with apply function to remove rows that contains a specific number.ExampleCreate the data frameLet’s create a data frame as shown below −M

To convert values greater than a threshold into 1 in R data frame column, we can follow the below steps −First of all, create a data frame.Then, use ifelse function to convert values greater than a threshold into 1.ExampleCreate the data frameLet’s create a data frame as shown below −x

To subset R data frame rows if at least one or more values matches, we can follow the below steps −First of all, create a data frame.Then, use rowSums function along with sapply function and values for match to subset the data frame rows if at least one or more values matches.ExampleCreate the data frameLet’s create a data frame as shown below −x

To repeat column values in R data frame by values in another column, we can follow the below steps −First of all, create a data frame.Then, use rep function along with cbind function to repeat column values in the matrix by values in another column.ExampleCreate the data frameLet’s create a data frame as shown below −x

To standardize selected columns in R data frame, we can follow the below steps −First of all, create a data frame.Then, use scale function with subsetting to standardize selected columns.ExampleCreate the data frameLet’s create a data frame as shown below −v1

To convert a data frame into two column data frame with values and column name as variable in R, we can follow the below steps −First of all, create a data frame.Then, use stack function to convert data frame.ExampleCreate the data frameLet’s create a data frame as shown below −x

To extract number from string if string is in different format than normal in R data frame, we can follow the below steps −First of all, create a data frame.Then, use gsub function along with as.numeric function to extract the number.ExampleCreate the data frameLet’s create a data frame as shown below −x

To extract number from string in R data frame, we can follow the below steps −First of all, create a data frame.Then, use gsub function to extract number from string.ExampleCreate the data frameLet’s create a data frame as shown below −x