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
Articles on Trending Technologies
Technical articles with clear explanations and examples
How to convert a character data frame to numeric data frame in R?
Sometimes numerical values are recorded as character values and we need to convert them to numeric type before starting our analysis. This is also possible for a whole data frame in R. Therefore, we can use sapply function to convert the columns of the data frame to numeric type and save the output in a data frame by reading it with as.data.frame.Example1Consider the below data frame −x
Read MoreCount of cells in a matrix which give a Fibonacci number when the count of adjacent cells is added in C++
Given a matrix [ ][ ] having dimensions as row x col. The goal is to find the count of cells of matrix that meet the given condition:Value of cell matrix [i][j] + no. of adjacent cells to it = a Fibonacci numberNumbers in Fibonacci series:- 0, 1, 1, 2, 3, 5, 8, 13, 21, 43 …..Let us understand with examples.For ExampleInput - matrix[row][col] = {{1, 4, 1}, {2, 0, 1}, {5, 1, 1}Output - Count of cells in a matrix which give a Fibonacci number when the count of adjacent cells is added are: 4Explanation 0 1 ...
Read MoreHow to create bins for a continuous vector in R?
To create the bins for a continuous vector, we can use cut function and store the bins in a data frame along with the original vector. The values in the cut function must be passed based on the range of the vector values, otherwise, there will be NA’s in the bin values. For example, if we have a vector that contains 0.55 and we do not use 0 in the cut function then the first bin will be NA. Check out the below examples to understand how to properly do it.Example1x1
Read MoreCount of different ways to express N as the sum of 1, 3 and 4 in C++
Given a positive number N as input. The goal is to find the number of ways in which we can express N as a sum of 1s, 3s and 4s only. For example, if N is 4 then it can be represented as 1+1+1+1, 3+1, 1+3, 4 so the number of ways will be 4.Let us understand with examples.For ExampleInput - N=5Output - Count of different ways to express N as the sum of 1, 3 and 4 are: 6Explanation - 5 can be represented as:1+1+1+1+11+3+13+1+11+1+34+11+4Input - N=6Output - Count of different ways to express N as the sum of ...
Read MoreHow to convert matrix rows into a list in R?
Depending on our objective, a matrix rows might be needed to converted into a list that means each row will be an element of the list. This can be done by using the function as.list but firstly we need to convert the matrix into data frame after transposing. For example, if we have a matrix called M then it’s rows will be converted to a list using the command writtem below −as.list(data.frame(t(M)))Example1M1
Read MoreCount of n digit numbers whose sum of digits equals to given sum in C++
Given a positive number as the number of digits and a sum. The goal is to find all d digit numbers that have sum of digits equal to the input sum. The numbers having leading zeros will not be considered as d digit numbers.The ranges are digits between 1 to 100 and sum between 1 and 500.Let us understand with examples.For ExampleInput - digits = 3, digi_sum = 3Output - Count of n digit numbers whose sum of digits equals to given sum are: 6Explanation - Three digit numbers having sum of digits as 3 are:102, 111, 120, 201, 210, ...
Read MoreHow to find the mean of multiple columns based on a character column in R?
If we have a character column that means we are more likely to have duplicated values in that column hence finding the mean of numerical columns based on the values in character column cannot be done directly. For this purpose, we can use aggregate function as shown in the below examples.Example1Consider the below data frame −set.seed(214) x1
Read MoreCount of Numbers in Range where first digit is equal to last digit of the number in C++
Given a range of numbers between start and end. The goal is to find the count of numbers that have the first digit equal to the last digit and fall in the range [ first, last ].All single digit numbers will be counted if they lie in the range.Let us understand with examples.For ExampleInput - start = 100, end = 200Output - Count of Numbers in Range where first digit is equal to last digit of the number are: 10Explanation - The numbers will be:101, 121, 131, 141, 151, 161, 171, 181 and 191.Input - start = 1, end = ...
Read MoreCount sub-matrices having sum divisible 'k' in C++
Given a row x col matrix as input. The goal is to find all submatrices within the matrix[row][col] such that the sum of elements of that submatrix is divisible by integer k.If the matrix is mat[3][3] and k is 4 then submatrices will be as shown below:- Let us understand with examples.For ExampleInput - matrix[3][3] = { {1, 1, 1}, {2, 2, 2}, {3, 3, 3} } k=4Output - Count of sub-matrices having sum divisible 'k' are: 4Explanation - The submatrices will be as shown in above.Input - matrix[3][3] = { {1, 1, 1}, {2, 2, 2 }, {3, 3, ...
Read MoreCount of numbers satisfying m + sum(m) + sum(sum(m)) = N in C++
Given a number N as input. The goal is to find numbers m upto N that satisfy the following condition. Here N
Read More