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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to convert columns of an R data frame into a single vector?
Sometimes all the columns in a data frame have similar data characteristics representing a particular variable. For example, having a data frame containing five columns each with heights of people. To convert this type of data frame into a vector we can use as.vector function along with the as.matrix function. The as.matrix will read the data frame columns so that the array of values can be created.Example1y1
Read MoreBubble Sort in Go Lang
Bubble Sort is a sorting algorithm that works by swapping the elements that are in the wrong order. In multiple passes, it checks if the adjacent elements are in the right order (increasing) or not.The Time Complexity of the Bubble Sort is O(n^2) since it takes two nested loops to check the adjacent element.For example, let’s take the following unsorted array −22 15 11 45 13Bubble Sort Algorithm first traverses the whole array and then in another loop checks if the adjacent elements are in order or not.Thus, after sorting the elements will be, 11 13 15 22 45AlgorithmIn two ...
Read MoreHow to select positive values in an R data frame column?
We know that positive values are greater thandf1$x[which(df1$x>0)]Example1set.seed(254) x
Read MoreWrite a Golang program to search an element in an array
Definition: A number is that is greater than 2 and divisible only by itself and 1.Examples: Prime numbers are 2, 3, 5, 7, 11, 13, 113, 119, ..., etc.Approach to solve this problemStep 1: Find square root of the given number, sq_root = √numStep 2: If the given number is divisible by a number that belongs to [2, sq_root], then print “Non Prime Number”Step 3: If not divisible by any number, then print “Prime Number”Programpackage main import ( "fmt" "math" ) func checkPrimeNumber(num int) { if num < 2 { fmt.Println("Number must be greater than 2.") return } sq_root := int(math.Sqrt(float64(num))) for i:=2; i
Read MoreHow to save a plot in pdf in R?
To save a plot in pdf, we can use the pdf function in base R. For example, if we want to save a plot with the name PDF then it can be done using the below command −pdf("PDF.pdf")After this we can create the plot and use dev.off().Examplepdf("pdfExample.pdf") plot(1:10)OutputExampledev.off()OutputTo check where it is saved, find the working directory using getwd().
Read MoreWrite a Golang program to find the factorial of a given number (Using Recursion)
ExamplesFactorial of 5 = 5*4*3*2*1 = 120Factorial of 10 = 10*9*8*7*6*5*4*3*2*1 =Approach to solve this problemStep 1: Define a function that accepts a number (greater than 0), type is int.Step 2: If the number is 1, then return 1.Step 3: Otherwise, return num*function(num-1).Programpackage main import "fmt" func factorial(num int) int{ if num == 1 || num == 0{ return num } return num * factorial(num-1) } func main(){ fmt.Println(factorial(3)) fmt.Println(factorial(4)) fmt.Println(factorial(5)) }Output6 24 120
Read MoreWrite a Golang program to swap two numbers without using a third variable
Approach to solve this problemStep 1: Define a function that accepts two numbers, type is int.Step 2: Find b = a + b;Step 3: Then a = b – a and b = b – aProgrampackage main import "fmt" func swap(a, b int){ fmt.Printf("Before swapping, numbers are %d and %d", a, b) b = a + b a = b - a b = b - a fmt.Printf("After swapping, numbers are %d and %d", a, b) } func main(){ swap(23, 45) swap(56, 100) }OutputBefore swapping, numbers are 23 and 45 After swapping, numbers are 45 and 23 Before swapping, numbers are 56 and 100 After swapping, numbers are 100 and 56
Read MoreCan we override default methods in Java?
An interface in Java is similar to class but, it contains only abstract methods and fields which are final and static.Since Java8 static methods and default methods are introduced in interfaces. Unlike other abstract methods these are the methods can have a default implementation. If you have default method in an interface, it is not mandatory to override (provide body) it in the classes that are already implementing this interface.In short, you can access the default methods of an interface using the objects of the implementing classes.Exampleinterface MyInterface{ public static int num = 100; public default void ...
Read MoreHow to create the stacked bar plot using ggplot2 in R with labels on the plot?
The creation of stacked bar plot using ggplot2 can be done with the help of position="stack" argument inside geom_bar function. If we want to create the stacked bar plot then geom_text function will be used with the same position argument and the aes to define the labels as shown in the below example.Exampledf
Read MoreWrite a Golang program to print the Fibonacci series
Definition: In a Fibonacci series, the next number would be the summation of its two previous numbers, series starting from 0 and 1.ExamplesPrint a fibonacci series up to num = 10;Series: 1, 2, 3, 5, 8, next is 13 but greater than 10;Approach to solve this problemStep 1: Define a function that accepts a numbers(num) type is int, till then need to print the series.Step 2: Take two initial numbers for the series, i.e., 0 and 1.Step 3: Start a true for loop and declare a third variable to store previous two values.Step 4: Print the summation of two numbers until ...
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