Server Side Programming Articles - Page 741 of 2650

To scale some columns in data.table object in R, we can follow the below steps −First of all, create a data.table object.hen, subset the columns with single square brackets and use lapply, list and scale function to scale those columns.ExampleCreate the data.table objectLet’s create a data.table object as shown below −library(data.table) var1

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

If we have a data frame where row indices are not in correct sequence then we can set them to NULL to get the correct sequence of row numbers starting from 1.For example, if we have a data frame called df which has row ordered in an inappropriate way then we can reorder the row indices in correct order by using the command given below −row.names(df)

To print the exact values of all elements in a column of an R data frame, we can follow the below stops −First of all, create a data frame.Then, use options function and provide the required number of digits for printing.ExampleCreate the data frameLet’s create a data frame as shown below −x

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

To change the color code of corrplot, we can use colorRampPalette function inside corrplot function. We can provide different colors in colorRampPalette that we want to display in the corrplot.Check out the below given example to understand how it can be done.ExampleFollowing snippet creates a sample data frame −x

To check if two vectors are exactly same, we can use identical function.For example, if we have two vectors say x and y then we can find whether both of them are exactly same or not by using the command given below −identical(x,y)Check out the below examples to understand the result of identical function for two vectors.Example 1To check if two vectors are exactly same, use the command given below −x1

To find the ID wise frequency in an R data frame, we can use summarise function of dplyr package after defining the ID with group_by function, also the column for which we want to find the frequency will be placed inside group_by function.Check out the below examples to understand how it can be done.Example 1Following snippet creates a sample data frame −ID

To find the mean of all columns by group, we can use summarise_all function along with mean function after defining the groups with group_by. For example, if we have a data frame called df that contains a grouping column say G and some numerical columns then we can find the mean of all columns by values in grouping column by using the below given command −df%>%group_by(G)%>%summarise_all("mean")Example 1Following snippet creates a sample data frame −Grp

To find the mean of every n values in an R vector, we would first need to convert the vector into matrix with number of rows based for n values then we can use colMeans function.For example, if we have a vector called X that contains hundred values then we can find the mean of every ten value by using the command given below −colMeans(matrix(X,10))Example 1To find the mean of every n values in an R vector, use the command given below −x1