Article Categories
- All Categories
-
Data Structure
-
Networking
-
RDBMS
-
Operating System
-
Java
-
MS Excel
-
iOS
-
HTML
-
CSS
-
Android
-
Python
-
C Programming
-
C++
-
C#
-
MongoDB
-
MySQL
-
Javascript
-
PHP
-
Economics & Finance
Server Side Programming Articles
Page 1222 of 2109
How to find the absolute distance between columns of an R data frame?
The absolute distance can be found by calculating the difference between column values. And if we want the distance to be absolute then we would be need to use abs function. For example, suppose we have a data frame df that contain columns x and y then the absolute distance can be found by using df$Absolute_Distance set.seed(274) > x1 y1 df1 df1Output x1 y1 1 6 11 2 1 4 3 4 2 4 7 12 5 4 5 6 6 10 7 6 14 8 6 8 9 2 11 10 3 8 11 3 8 12 2 6 ...
Read MoreNumber of Connected Components in an Undirected Graph in C++
Suppose we have n nodes and they are labeled from 0 to n - 1 and a list of undirected edges, are also given, we have to define one function to find the number of connected components in an undirected graph.So, if the input is like n = 5 and edges = [[0, 1], [1, 2], [3, 4]], then the output will be 2To solve this, we will follow these steps −Define a function dfs(), this will take node, graph, an array called visited, if visited[node] is false, then −visited[node] := truefor initialize i := 0, when i < size ...
Read MoreHow to find the minimum and maximum of columns values in an R data frame?
The range function in R provides the minimum and maximum values instead of the difference between the two. Hence, we can find the minimum and maximum by using range function but for a data frame we cannot use it directly. Check out the below examples to understand how it works.Example1> set.seed(974) > x1 x2 x3 df1 df1Output x1 x2 x3 1 0 6 10 2 0 7 10 3 3 3 11 4 2 7 9 5 3 2 5 6 3 4 7 7 2 7 7 8 2 8 5 9 0 4 9 10 2 2 11 ...
Read MoreLargest BST Subtree in C++
Suppose we have a binary tree; we have to find the largest subtree of it where largest means subtree with largest number of nodes in it.So, if the input is like, then the output will be 3, as the Largest BST Subtree, in this case, is the highlighted one.To solve this, we will follow these steps −Define one structure called data, there will be four values, size, maxVal, minVal, and ok, the ok can hold only true/false valuessolve(TreeNode * node)if node is null, then &miuns;return Data by initializing (0, infinity, -infinity, true)left := solve(left of node)left := solve(right of node)Define ...
Read MoreAndroid Unlock Patterns in C++
Suppose we have an Android 3x3 key lock screen and two integers m and n, the values of m and n are in range 1 ≤ m ≤ n ≤ 9, We have to count the total number of unlock patterns of the Android lock screen, which consist of minimum of m keys and maximum n keys.The rule is like, each pattern must connect at least m keys and at most n keys. All the keys must be unique. If there is a line connecting two consecutive keys in the pattern passes through any other keys, the other keys must ...
Read MoreHow to create a covariance matrix in R?
To create a covariance matrix, we first need to find the correlation matrix and a vector of standard deviations is also required. The correlation matrix can be found by using cor function with matrix object. For example, if we have matrix M then the correlation matrix can be found as cor(M). Now we can use this matrix to find the covariance matrix but we should make sure that we have the vector of standard deviations.Example1> M1 M1Output [, 1] [, 2] [, 3] ...
Read MoreHow to create a plot using rgb colors in R?
The rgb colors are referred to red green and blue. This combination helps us to create many different colors. In R, we can use rgb function to create a plot using with different colors along with the image function. If we want to have a plot with rgb colors without any axes title or axes labels then the appropriate arguments should be used inside the image function as shown in the below example.ExampleConsider the below data frame:> set.seed(9991) > x1 x2 x3 df dfOutput x1 x2 ...
Read MoreHow to remove rows based on blanks in a column from a data frame in R?
Sometimes data is incorrectly entered into systems and that is the reason we must be careful while doing data cleaning before proceeding to analysis. A data collector or the sampled unit might enter blank to an answer if he or she does not find an appropriate option for the question. This also happens if the questionnaire is not properly designed or blank is filled by mistake. Also, if we have categorical variable then a control category might be filled with blank or we may want to have a blank category to use a new one at later stage. Whatever the ...
Read MoreHow to create a bar plot using ggplot2 with one bar having black border in R?
The bar plot can be easily created with the help of geom_bar. But if we want to have a different border for a particular bar then we first need to create the bar plot and store it in an object. After that we need to add the original plot with the bar for which we want to have a black border. Check out the below example to understand how it can be done.ExampleConsider the below data frame:> Group Freq df dfOutput Group Freq 1 G1 18 2 G2 27 3 G3 24Loading ggplot2 package ...
Read MoreHow to find the column means of a column based on another column values that represent factor in an R data frame?
If we have a column that represent factor then we might want to find the mean of values in other column(s) for the factor levels. This is helpful in comparing the levels of the factor. In R, we can find the mean for such type of data by using aggregate function. Check out the below examples to understand how it can be done.Example1Consider the below data frame:> x1 y1 df1 df1Output x1 y1 1 D 5.801197 2 B 3.432060 3 B 6.154168 4 A 5.466655 5 D 5.171689 6 C 5.175170 7 B 5.353469 8 D 4.840470 ...
Read More