Programming Articles - Page 891 of 3366

To extract a particular level from factor column in an R data frame, we can use levels function with the number of the factor.For Example, if we have a data frame called df that contains a factor column say F then we can find the third level in F by using the below given command −levels(df$F)[2]Example 1Following snippet creates a sample data frame −Grp

To find the count of each category in a data.table object column in R, we can follow the below steps −First of all, create a data.table object.Then, use summarise function of dplyr package after grouping along with n.ExampleCreate the data.table objectLet’s create a data.table object as shown below −library(data.table) factor

When we create a general linear model for logistic regression model, we need to specify the distribution family as binomial. The error “NA/NaN/Inf” occurs when we do not specify the distribution family. Hence, family="binomial" needs to be used inside glm function while creating the logistic regression model.Example 1Following snippet creates a sample data frame −iv1

To check if a set is a subset of another set, we can use all function with %in% operator. For example, if we have two vectors say x and y and we want to check whether x is a subset of y then we can use the command given below −all(x %in% y)Check out the below given examples to understand how it works.Example 1To check if a set is a subset of another set in R, use the snippet given below −set_x1

To split a number into digits in R, we can use strsplit function by reading the number with as.character and then reading the output with as.numeric.For example, if we have a number stored into an object called X then we can split the number stored in X into digits by using the command as follows −as.numeric(strsplit(as.character(X),"")[[1]])Example 1To split a number into digits in R, use the snippet given below −x1

To round each value to two decimal places 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 to two decimal places in columns if some columns are categorical.ExampleCreate the data frameLet’s create a data frame as shown below −Level

A sequence vector is created by using the sequence of numbers such as 1 to 15, 21 to 51, 101 to 150, -5 to 10. The length of this type of vectors can be found only by using the length function.For example, if we have a sequence vector say X then the length of X can be found by using the command given below −length(X)Example 1To find the length of sequence vector in R, use the code given below −x1

To find the percentiles for multiple columns in R data frame, we can use apply function with quantile function and providing the quantile probabilities with probs argument.For Example, if we have a data frame called df that contains multiple columns and we want to find three percentiles 0.25, 0.70, 0.90 then we can use the command given below −apply(df[],2,quantile,probs=c(0.25,0.70,0.90))Example 1Following snippet creates a sample data frame −x1

To find the log 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 log if some columns are categorical.ExampleCreate the data frameLet’s create a data frame as shown below −Level

To find the cross product of two vectors in R by adding the elements, we can calculate outer product by using %o% operator.For example, if we have two vectors say x and y then cross product of these two vectors by adding the elements can be found by using the command given below −x%o%yCheck out the below examples to understand how it works.Example 1To find the cross product of two vectors in R by adding the elements, use the code given below −x1