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R Programming Articles
Page 48 of 174
How to create a plot of Poisson distribution in R?
The Poisson distribution is a discrete distribution that has only one parameter named as lambda and it is the rate parameter. The rate parameter is defined as the number of events that occur in a fixed time interval. To create a plot of Poisson distribution in R, we can use the plot function with the density of the Poisson distribution using dpois function.Exampleplot(dpois(x=1:50,lambda=3))OutputExampleplot(dpois(x=1:50,lambda=3),type="l")OutputExampleplot(dpois(x=1:50,lambda=3),type="b")Output
Read MoreHow to create a matrix without column and row indices in R?
To create a matrix without column and row indices, we first need to create the matrix and then prmatrix function can be used to convert that matrix without column and row indices but we would need to provide the number of rows inside the function. For example, if we have a matrix M that contains 5 rows and 5 columns then it can be converted to a matrix without column and row indices using prmatrix(M,rowlab=rep("",5),collab=rep("",5)).ExampleM1
Read MoreHow to find the maximum of each row in an R data frame?
Sometimes we need maximum values, it helps us to identify which case or subject occurs at the greatest point hence we can understand the limit for the sample or population under study. If we want to find the maximum of values two or more columns for each row in an R data frame then pmax function can be used.ExampleConsider the below data frame −set.seed(1997) x1
Read MoreHow to remove duplicate rows and sort based on a numerical column an R data frame?
If we have duplicate rows in an R data frame then we can remove them by using unique function with data frame object name. And if we want to order the data frame with duplicate rows based on a numerical column then firstly unique rows should be found then order function can be used for sorting as shown in the below examples.ExampleConsider the below data frame −x1
Read MoreHow to create a classification model using svm for multiple categories in R?
SVM is a supervised machine learning algorithm which can be used for both classification or regression challenges but mostly we use it for classification. The classification using svm can be done for two or more categories as well. In R, we can use simply use svm function of e1071 package.ExampleConsider the iris data −str(iris)Output'data.frame': 150 obs. of 5 variables: $ Sepal.Length: num 5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ... $ Sepal.Width : num 3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ... $ Petal.Length: num 1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 ...
Read MoreHow to find the table of ordered frequencies of vector elements in R?
We can create table of frequencies of a vector element by using table function and the ordering can be done by using sort function. If we want to order the frequencies in decreasing order then decreasing argument can be used. For example, if we have a vector x then the table of ordered frequencies can be created as sort(table(x)).Examplex1
Read MoreHow to divide row values of a numerical column based on categorical column values in an R data frame?
If we have a categorical column that has two or more categories and a numerical column then we might want to divide the one category numerical value from other category numerical value. This can be done by using divide sign / but we need to use the proper subset of the values.ExampleConsider the below data frame −x1
Read MoreHow to save list where each element contains equal number of values to a text file in R?
If we want to save a list to a text file then first step would be converting that list to a data frame then write.table function can be used for saving. For example, if we have a list defined as LIST and it has elements each containing 50 values then we can convert it to a data frame as −LIST_df=as.data.frame(do.call(cbind,LIST))Now we can save it as −write.table(LIST_df,"LIST.txt")ExampleConsider the below list −x1
Read MoreHow to generate a probability density distribution from a set of observations in R?
The probability density distribution is the synonym of probability density function. It is a function that defines the density of a continuous random variable. In R, we can use density function to create a probability density distribution from a set of observations.Examplex1
Read MoreHow to set comma as decimal separator in R?
In European countries, a comma is used to separate the integral part of a number from the decimal part. Thus, we might want to create data or perform calculations with comma as decimal separator. In R, we can do this by just using the code options(OutDec=", "). Once we will type this in R console, all the numerical values with decimals will be printed with commas in place of dots.Exampleoptions(OutDec=", ") rnorm(10)Output[1] 0, 14421957 -0, 24152088 -0, 05215867 -0, 40577010 0, 19806357 -1, 49349808 [7] 0, 91085263 0, 43550033 2, 64009603 1, 17177332Examplernorm(50)Output[1] -0, 56186368 -2, 11404777 0, 99584461 -2, ...
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