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To multiply corresponding values from two data.table objects in R, we can follow the below steps −First of all, create two data.table objects.Then, use mapply function to multiply corresponding values from those two data.table objects.ExampleCreate the first data.table objectLet’s create a data.table object as shown below −library(data.table) x1
To display both axes’ labels of a ggplot2 graph in italics in R, we can use theme function where we can set the face of axis.text.x and axis.text.y argument to italic.For Example, if we have a data frame called df that contains two columns say X and Y then we can create a scatterplot of X and Y with axes labels in italics by using the below mentioned command −ggplot(df, aes(X, Y))+geom_point()+theme(axis.text.x=element_text(face="italic"), axis.text.y=element_text(face="italic"))ExampleFollowing snippet creates a sample data frame −xRead More
To find the percentage of zeros in each column of a matrix in R, we can follow the below steps −First of all, create a matrix.Then, use colSums function along with nrow function to find the percentage of zeros in each column.Example 1Create the matrixLet’s create a matrix as shown below −M1
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 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 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 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 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