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Page 1178 of 2109
How to find the mean of three-dimensional array in R?
A three-dimensional array can have matrices of different size and they are not necessarily to be square or rectangular. Also, all the elements in an array are of same data type. If we want to find the mean of a three-dimensional array then apply function can be used where we need to refer the columns and rows of the array elements using combination function.ExampleA1 apply(A1,c(1,2),mean) [,1] [,2] [1,] 5 7 [2,] 6 8ExampleA2
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 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 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, ...
Read MoreHow to remove list elements by their name in R?
Data analysis not only includes mathematical operations, we have to spend a lot of time in data cleaning, data mining, feature engineering etc. One operation could be removing list elements by their name if they are not helpful to achieve our objective. The removal of the elements by using their names can be done with the help of which function.ExampleConsider the below list List1
Read MoreHow to generate standard normal random numbers in R?
A standard normal distribution is the type of distribution that has mean equals to zero with standard deviation 1. If we want to generate standard normal random numbers then rnorm function of R can be used but need to pass the mean = 0 and standard deviation = 1 inside this function.Examplernorm(10, 0, 1)Output[1] 0.6936607 -0.7967657 -2.7544428 0.2688767 0.5278463 -1.5387568 [7] 1.1716632 -1.5033895 0.8112929 -1.0101065Examplernorm(50, 0, 1)Output[1] 2.58246666 -0.53083341 -0.57343343 1.08172756 1.30341849 -0.07440422 [7] -0.41869305 -0.96227706 -0.46899119 1.55428279 0.09162738 -0.96027221 [13] -0.84735327 -1.74949782 0.58541758 0.23117630 0.47402479 -0.72453853 [19] 0.07171564 1.13088794 0.18735157 0.25091758 -1.34728315 -0.39768159 [25] -0.38109955 -0.34019286 -1.51778561 -0.92222239 -1.22798041 ...
Read MoreHow to perform one-way anova with unequal sample sizes in R?
To perform the one-way anova with sample sizes having different sizes we can use aov function. Suppose we have a categorical column defined as Group with four categories and a continuous variable Response both stored in a data frame called df then the one-way anova can be performed as −aov(Response~Group,data=df)ExampleConsider the below data frame −Group
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