R Programming Articles - Page 37 of 204

Sometimes we want to graphs that looks like graphs on a white paper having no axes labels, axes titles, and ticks, therefore, we can use theme_classic function of ggplot2 package.For Example, if we have a data frame called df that contains two columns say x and y then we can create the scatterplot between x and y using ggplot2 that looks like printed on white paper by using the below given command −ggplot(df,aes(x,y))+geom_point()+theme_classic(base_size=0)ExampleFollowing snippet creates a sample data frame −x

To extract the first n values of all elements of a list in R, we can follow the below steps −First of all, create a list.Then, use head function with sapply function to extract the first n values of all elements in the list.Example 1Create the listLet’s create a list as shown below −List1

To extract the last value of all elements of a list in R, we can follow the below stepss −First of all, create a list.Then, use tail function with sapply function to extract the last value of all elements in the list.Example 1Create the listLet’s create a list as shown below −List

To repeat a whole data.table object in R, we can follow the below steps −First of all, create a data.table object.Then, use rep function to repeat the data.table object.ExampleCreate the data.table objectLet’s create a data.table object as shown below −library(data.table) x

To find the number of columns where all row values are equal in data.table object in R, we can follow the below steps −First of all, create a data.table object.Then, use sum function along with length and apply function to find the number of columns where all row values are equal.Example 1Create the data.table objectLet’s create a data.table object as shown below −library(data.table) x

To find the position of maximum of each numerical column 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 maximum of each numerical column if some columns are categorical.Example 1Create the data frameLet’s create a data frame as shown below −Level

To find the cosine of 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 find the cosine of each value in columns if some columns are categorical.ExampleCreate the data frameLet’s create a data frame as shown below −Level

To create a binary random variable in R with given probability, we can use the rbinom function with sample size argument n, success size argument size, and probability argument prob. To understand, how it can be done check out the below examples.Example 1Create the vector using rbinom function with n = 500, size = 1, and prob = 0.05 as shown below −x1

To find the column median 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 column median if some columns are categorical.Example 1Create the data frameLet’s create a data frame as shown below −Group

To create a replacement column with multiple conditions and NA in R data frame, we can follow the below steps −First of all, create a data frame.Then, use nested ifelse function to create a replacement column with multiple conditions.ExampleCreate the data frameLet’s create a data frame as shown below −x