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Articles by Nizamuddin Siddiqui
Page 143 of 196
How to find the maximum of factor levels in numerical column and return the output including other columns in the R data frame?
When we have factor column that helps to differentiate between numerical column then we might want to find the maximum value for each of the factor levels. This will help us to compare the factor levels in terms of their maximum and if we want to do this by getting all the columns in the data frame then aggregate function needs to be used with merge function.Consider the below data frame −Example Live Demoset.seed(78) Group
Read MoreHow to take a subset of a matrix in R with finite values only if the matrix contains NA and Inf values?
If we have a matrix that contains NA or Inf values and we want to take the subset of that matrix with finite values then only the rows that do not contain NA or Inf values will be the output. We can do this in R by using rowSums and is.finite function with negation operator !.Example Live Demoset.seed(999) M1
Read MoreHow to find the index of the last occurrence of repeated values in a vector in R?
Indexing helps us to understand the location of the value in the vector. If we have a vector that contains repeated values then we might want to figure out the last occurrence of the repeated value. For example, if we have a vector x that contains 1, 1, 2, 1, 2 then the last occurrence of repeated values will be 4 and 5 because the last 1 is at 4th position and 2 is at the 5th position. We can find this by using tapply function in R.Example Live Demox1
Read MoreHow to join points in a point chart with lines using ggplot2 in R?
Usually, a point chart is created to assess the relationship or movement of two variables together but sometimes these points are scattered in a way that makes confusion. Hence, data analyst or researcher try to visualize this type of graph by joining the points with lines. In ggplot2, this joining can be done by using geom_line() function.Consider the below data frame −Example Live Demoset.seed(111) x
Read MoreHow to generate a normal random vector using the mean of a vector in R?
To create a normal random vector, we can use rnorm function with mean and standard deviation as well as without passing these arguments. If we have a different vector derived from another distribution or simply represent some numbers then we can use the mean of that vector in the rnorm function for mean argument.Example Live Demoset.seed(101) x1
Read MoreHow to find prime numbers between two values or up to a value in R?
We know that the prime numbers are the numbers that are not divisible by any number except by themselves or 1 and 1 is not considered as a prime number. In R, we can find the prime numbers up to a number or between two numbers by using Prime function of numbers package. If we want to find the total number of prime numbers between 1 and 10, then we just need to pass 10 inside the Prime function, otherwise range will be required.Loading numbers package −library("numbers")Primes(10)[1] 2 3 5 7Primes(100)[1] 2 3 5 7 11 13 17 19 23 ...
Read MoreHow to find the difference between regression line and the points in R?
The difference between regression line and the points on the scatterplot are actually the residuals, thus we need to calculate the residual from the model object. This can be simply done by using residuals function. For example, if we create a linear model defined as Model between x and y then the residuals will be found as residuals(Model).Consider the below data frame −Example Live Demoset.seed(999) x1
Read MoreHow to convert rows in an R data frame to list?
Sometimes each row needs to be treated differently, therefore, we might want to convert those rows into list. This will help us to perform the operations on our row elements separately. To convert the rows into list, we can use split function by defining the number of rows in the data frame.Consider the below data frame −Example Live Demoset.seed(101) x1
Read MoreHow to combine two matrices to create a block-diagonal matrix in R?
A block-diagonal matrix means that a matrix added to another matrix at the end the last element. For example, if we have a matrix with nine values and the other matrix also has nine values then the second matrix will be added to the first matrix and the elements below first matrix will be zero and the elements above the second matrix will also be zero.Example Live DemoM1
Read MoreHow to find the cube root of negative values in R?
There is no function in R to find the cube root of negative values, hence we need to create that. The code to create the function is as shown below −CubeRoot
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