Programming Articles - Page 887 of 3363

If we have multiple matrices and we want to combine the rows of those matrices alternately then we would first need to find the order of the matrices with order function along with sequence and sapply function after reading the matrices with list after that the values will be combined with rbind function.Check out the Example given below to understand how it can be done.ExampleFollowing snippet creates a sample matrix −M1

To replace all values in an R data frame if they are greater than a certain value, we can use apply function with ifelse function.For Example, if we have a data frame called df and we want to replace all values in df with 5 if they are greater than 10 then we can use the command given below −df[]

The error hist.default, 'x' must be numeric occurs when we pass a non-numerical column or vector to the hist function. If we have a non-numerical column in a data frame or a non-numerical vector and we want to create the histogram of that data can be created with the help of barplot and table function.Check out the below given Exampleto understand how it can be done.ExampleFollowing snippet creates a sample data frame −x

To create a column of log with base 2 in data frames stored in R list, we can follow the below steps −First of all, create a list of data frames.Then, use lapply function to create a column of log with base 2 in data frames stored in the list.ExampleCreate the list of data framesUsing data.frame function to create data frames and list function to create the list of those data frames −df1

To create a column of natural log in data frames stored in R list, we can follow the below steps −First of all, create a list of data frames.Then, use lapply function to create a column of natural log in data frames stored in the list.ExampleCreate the list of data framesUsing data.frame function to create data frames and list function to create the list of those data frames −df1

To create a data frame with numerical as well as factor columns in R, we simply need to add factor function before factor columns and numerical columns will be created without mentioning any specific characteristics, the values of numerical columns just need to be numerical in nature.Example 1Following snippet creates a sample data frame df1 with factor and numerical column −Gender

To create a column of raise to the power 3 in data frames stored in R list, we can follow the below steps −First of all, create a list of data frames.Then, use lapply function to create a column of raise to the power 3 in data frames stored in the list.ExampleCreate the list of data framesUsing data.frame function to create data frames and list function to create the list of those data frames −df1

To create a column of square root in data frames stored in R list, we can follow the below steps −First of all, create a list of data frames.Then, use lapply function to create a column of square root in data frames stored in the list.ExampleCreate the list of data framesUsing data.frame function to create data frames and list function to create the list of those data frames −df1

To randomize rows of a matrix in R, we can use sample function along with nrow function to get the random rows and then subset the matrix with single square brackets.For example, if we have a matrix called M then randomization of rows in M can be done by using the command given below − Random_rows

To create a column of square in data frames stored in R list, we can follow the below steps −First of all, create a list of data frames.Then, use lapply function to create a column of square in data frames stored in the list.ExampleCreate the list of data framesUsing data.frame function to create data frames and list function to create the list of those data frames −df1