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Articles by Nizamuddin Siddiqui
Page 131 of 196
How to make all the elements in a list of equal size in R?
We know that a list can multiple elements of different types as well as of different size. For example, a list that contains two elements then one element may contain fifteen elements and the other might have twenty-five elements. In this situation, we might want to fill the first element with ten more elements so that the size of both the elements become equal. This can be done by using lapply function as shown in the below examples.Consider the below list −Example Live Demoset.seed(101) x1
Read MoreHow to generate Bernoulli random variable in R?
Each value in Bernoulli random variable represents success or a failure for a single trial that makes it different from Binomial random variable because a Binomial random variable represents number of success or failure for a number of trials. To generate a Bernoulli random variable, we can use rbinom function but we need to pass 1 for size argument.Example Live Demorbinom(120, 1, 0.71)Output[1] 1 1 1 1 1 1 0 0 0 1 1 1 1 1 1 1 1 1 1 0 0 0 1 1 1 0 0 0 1 1 1 1 1 1 1 0 ...
Read MoreHow to count the number of occurrences of all unique values in an R data frame?
A data frame in R can have infinite number of unique values and it can also contain many repeated values. Therefore, finding the number of all unique values in the data frame can help us to understand the diversity in the data but this most done in situations where we expect to have repeated elements otherwise it would not make sense. To count the number of occurrences of all unique values, we can use table function along with the unlist as shown in the below examples.Consider the below data frame −Example Live Demox1
Read MoreHow to perform homogeneity of variance test for two-way anova in R?
In general, we can say that the homogeneity of variance test is the type of test that compares the variance of two or more variables and finds the significant difference between or among them if exists. For a two-way anova, one of the most commonly used homogeneity of variance test is Levene’s Test and it can be easily done with the help of leveneTest function of car package in base R.Consider the below data frame −Example Live Demoset.seed(151) x1F) group 6 0.6593 0.6835 13
Read MoreHow to calculate the number of elements greater than a certain value in a vector in R?
In data analysis, sometimes we need to count the number of values that are greater than or less than a certain value, and this certain value could be a threshold. For example, we might have a vector that contain values for blood pressure of people and we might want check how many values are greater than 120. In this type of situation, we can use length function as shown in the below examples.Example Live Demox11])Output[1] 9 Example Live Demox25])Output[1] 93Example Live Demox35])Output[1] 42Example Live Demox40])Output[1] 108Example Live Demox51])Output[1] 107Example Live Demox65])Output[1] 31Example Live Demox71])Output[1] 21Example Live Demox84])Output[1] 19Example Live Demox9118])Output[1] 11Example Live Demox105000])Output[1] 68
Read MoreHow to create a graph in R using ggplot2 with all the four quadrants?
The default graph created by using ggplot2 package shows the axes labels depending on the starting and ending values of the column of the data frame or vector but we might want to visualize it just like we do in paper form of graphs that shows all of the four quadrants. This can be done by using xlim, ylim, geom_hline, and geom_vline functions with ggplot function of ggplot2 package.Consider the below data frame −Example Live Demox
Read MoreHow to create a subset of matrix in R using greater than or less than a certain value of a column?
Subsetting can be required in many different ways, we can say that there might be infinite number of ways for subsetting as it depends on the objective of the bigger or smaller analysis. One such way is subsetting a matrix based on a certain value of column of the matrix. In R, we can easily do the same with the help of subset function as shown in below example.Example Live DemoM3)Output [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [1,] 4 14 24 34 44 54 64 74 84 94 [2,] 5 15 25 35 45 55 65 75 85 95 [3,] 6 16 26 36 46 56 66 76 86 96 [4,] 7 17 27 37 47 57 67 77 87 97 [5,] 8 18 28 38 48 58 68 78 88 98 [6,] 9 19 29 39 49 59 69 79 89 99 [7,] 10 20 30 40 50 60 70 80 90 100Examplesubset(M,M[,1]75)Output[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [1,] 6 16 26 36 46 56 66 76 86 96 [2,] 7 17 27 37 47 57 67 77 87 97 [3,] 8 18 28 38 48 58 68 78 88 98 [4,] 9 19 29 39 49 59 69 79 89 99 [5,] 10 20 30 40 50 60 70 80 90 100Examplesubset(M,M[,9]>81)Output[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [1,] 2 12 22 32 42 52 62 72 82 92 [2,] 3 13 23 33 43 53 63 73 83 93 [3,] 4 14 24 34 44 54 64 74 84 94 [4,] 5 15 25 35 45 55 65 75 85 95 [5,] 6 16 26 36 46 56 66 76 86 96 [6,] 7 17 27 37 47 57 67 77 87 97 [7,] 8 18 28 38 48 58 68 78 88 98 [8,] 9 19 29 39 49 59 69 79 89 99 [9,] 10 20 30 40 50 60 70 80 90 100Examplesubset(M,M[,9]
Read MoreHow to find the sum of anti-diagonal elements in a matrix in R?
The anti-diagonal elements in a matrix are the elements that form straight line from right upper side to right bottom side. For example, if we have a matrix as shown below −1 2 3 4 5 6 7 8 9then the diagonal elements would be 1, 5, 9 and the anti-diagonal elements would be 3, 5, 7.To find the sum of these anti-diagonal elements, we can use apply function.Example Live DemoM1
Read MoreHow to find the correlation coefficient between rows of two data frames in R?
It is common the find the correlation coefficient between columns of an R data frame but we might want to find the correlation coefficient between rows of two data frames. This might be needed in situations where we expect that there exists some relationship row of an R data frame with row of another data frame. For example, row of an R data frame showing buying trend of a customer in one year and the same row of the other data frame showing buying trend of the same customer in another year.Consider the below data frame −Example Live Demox1
Read MoreHow to deal with warning message `stat_bin()` using `bins = 30`. Pick better value with `binwidth`. in R while creating a histogram?
The default value for bins is 30 but if we don’t pass that in geom_histogram then the warning message is shown by R in most of the cases. To avoid that, we can simply put bins=30 inside the geom_histogram() function. This will stop showing the warning message.Consider the below data frame −x
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