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Page 1274 of 2109
How to combine two vectors while replacing the NA values with the values in the other vector in R?
Sometimes we have vectors with NA values, also there might be a situation that one of vector having an NA at a position and the other vector has the numerical values at the same position. For example, 1, 2, NA and 1, 2, 3. In this case, we might want to combine these two vectors to make a single vector. This can be done by using coalesce function of dplyr package.Example> library(dplyr) > x1 x1Output[1] NA 4 NA 1 2 NA 4 1 4 1 2 3 1 4 2 2 NA 2 2 1Example> y1 y1Output[1] 1 2 3 ...
Read MoreHow to find the column and row indices of values in a matrix using which function in R?
To find the row and column indices of values in a matrix, we cannot simply use which function because it returns the index based on sequence of the numbers in the matrix. For example, if we have a matrix M as below −1 2 3 4 1 6 7 8 1Now if we try to find the index using which(M==1) then it will return 1 5 9Because 1 is placed at 1, 5 and 9.Hence, we need to use arr.ind = TRUE so that the matrix can be read as an array by which function.ExampleConsider the below matrix −> M ...
Read MoreMaximum sum of nodes in Binary tree such that no two are adjacent | Dynamic Programming In C++
In this tutorial, we will be discussing a program to find maximum sum of nodes in Binary tree such that no two are adjacent using Dynamic Programming.For this we will be provided with a binary tree. Our task is to find the subset having maximum sum such that no two nodes in the subset are directly connected using Dynamic Programming.Example#include using namespace std; //finding diameter using dynamic programming void dfs(int node, int parent, int dp1[], int dp2[], list* adj, int tree[]){ int sum1 = 0, sum2 = 0; for (auto i = adj[node].begin(); i != adj[node].end(); ...
Read MoreHow to find the number of distinct values in an R vector?
When we have repeated elements in an R vector and the vector size is large then we might want to know the distinct values in that vector. This will help us to understand the unique values we have in our vector, so that we can create the appropriate chart and perform the appropriate analysis using that vector. This can be done by using length function with unique.Examples> x1 x1Output[1] 2 5 5 3 2 4 3 3 1 4 5 4 5 3 3 1 1 2 5 1 3 2 4 1 3 1 5 4 2 5 5 ...
Read MoreHow to deal with missing values to calculate correlation matrix in R?
Often the data frames and matrices in R, we get have missing values and if we want to find the correlation matrix for those data frames and matrices, we stuck. It happens with almost everyone in Data Analysis but we can solve that problem by using na.omit while using the cor function to calculate the correlation matrix. Check out the examples below for that.ExampleConsider the below data frame −> x1 x2 x3 x4 df head(df, 20)Output x1 x2 x3 x4 1 2 2.6347839 4 2.577690 2 3 0.3082031 1 6.250998 3 1 0.3082031 3 7.786711 4 1 ...
Read MoreMaximum sum of nodes in Binary tree such that no two are adjacent in C++
In this tutorial, we will be discussing a program to find maximum sum of nodes in Binary tree such that no two are adjacent.For this we will be provided with a binary tree. Our task is to find the subset having maximum sum such that no two nodes in subset are directly connected.Example#include using namespace std; //binary tree node structure struct node { int data; struct node *left, *right; }; struct node* newNode(int data) { struct node *temp = new struct node; temp->data = data; temp->left = temp->right = NULL; return temp; } ...
Read MoreHow to add a new column in an R data frame with count based on factor column?
While doing the data analysis, often we have to deal with factor data and we might want to find the frequency or count of a level of factor and the other variable combination. This helps us to make comparison within and between factor levels. Therefore, we can add a new column as count to find the required frequency and it can be done by using group_by and mutate function of dplyr package.ExampleConsider the below data frame −> Group Rating df head(df, 20)Output Group Rating 1 A 1 2 B 6 3 C 2 4 ...
Read MoreMaximum sum of pairs with specific difference in C++
In this tutorial, we will be discussing a program to find maximum sum of pairs with specific difference.For this we will be provided with an array containing integers and a value K. Our task is to pair elements having difference less than K and finally find the maximum sum of the elements in disjoint sets.Example#include using namespace std; //returning maximum sum of disjoint pairs int maxSumPairWithDifferenceLessThanK(int arr[], int N, int K){ sort(arr, arr+N); int dp[N]; dp[0] = 0; for (int i = 1; i < N; i++) { dp[i] = dp[i-1]; ...
Read MoreHow to replace a value in an R vector?
To replace a value in an R vector, we can use replace function. It is better to save the replacement with a new object, even if you name that new object same as the original, otherwise the replacements will not work with further analysis. As you can see in the object x5(in examples), when we replaced 5 with 3, the previous replacement of -1 with 0 returned as in original vector. Therefore, we should save it in a new object.Examples> x1 x1Output[1] 1 2 3 4 5 6 7 8 9 10 > replace(x1, x1==5, 10)Output[1] 1 2 3 4 ...
Read MoreHow to calculate weighted mean in R?
Weighted mean is the average which is determined by finding the sum of the products of weights and the values then dividing this sum by the sum of total weights. If the weights are in proportion then the total sum of the weights should be 1. In base R, we have a function weighted.mean to find the weighted mean in which we just need to pass the vector of values and the vector of weights.Examplesx1
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