Programming Articles

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How to check which value is NA in an R data frame?

Nizamuddin Siddiqui
Nizamuddin Siddiqui
Updated on 03-Nov-2021 15K+ Views

To check which value in NA in an R data frame, we can use apply function along with is.na function.For Example, if we have a data frame called df that contains some NA values then we can check which value is NA by using the command mentioned below −apply(df,2, function(x) is.na(x))This will return the data frame in logical form with TRUE and FALSE. Check out the below Examples to understand how it works.Example 1Following snippet creates a sample data frame −x1

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Reduce the fraction to its lowest form in C++

Sunidhi Bansal
Sunidhi Bansal
Updated on 03-Nov-2021 6K+ Views

Given two integers Num1 and Num2 as input. The integers can be represented as fraction Num1/Num2. The goal is to reduce this fraction to its lowest form.Using GCD to find highest denominatorWe will calculate the greatest common divisor of both numbers.Divide both numbers by that gcdSet both variables as quotient after division.Lowest fraction will be Num1/Num2.ExamplesInput − Num1=22 Num2=10Output − Num1 = 11 Num2 = 5Lowest Fraction : 11/5Explanation− GCD of 22 and 10 is 2.22/2=11 and 10/2=5Lowest fraction is 11/5Input− Num1=36 Num2=40Output− Num1 = 9 Num2 = 10Lowest Fraction : 9/10Explanation − GCD of 36 and 40 is 4.40/4=10 and 36/4=9Lowest ...

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Reduce the array to a single element with the given operation in C++

Sunidhi Bansal
Sunidhi Bansal
Updated on 03-Nov-2021 334 Views

Given an integer variable Number as input. Let us consider an array containing elements in the range 1 to Number in sorted order. If we perform an operation on an array such that at each step the elements at odd positions are removed. Then the goal is to perform this operation N number of times till only a single element is left. Print that element at the end.Note-: The positioning of elements is such that the array at index 0 is at 1st position and so on.Test Cases for Number of elements in arrayInput Number=1, output = 1Input Number=2, output ...

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How to find the row sums if NA exists in the R data frame?

Nizamuddin Siddiqui
Nizamuddin Siddiqui
Updated on 03-Nov-2021 5K+ Views

To find the row sums if NA exists in the R data frame, we can use rowSums function and set the na.rm argument to TRUE and this argument will remove NA values before calculating the row sums.For Example, if we have a data frame called df that contains some NA values then we can find the row sums by using the below command −df$Row_Sums

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Reverse a number using stack in C++

Sunidhi Bansal
Sunidhi Bansal
Updated on 03-Nov-2021 2K+ Views

We are given an integer number Num as input. The goal is to find the reverse of the number using stack.Stack:- A stack is a data structure in C++ which stores data in LIFO ( Last in First Out) manner. Major operations of stack are-:Declaration-: stack stck; //stck is now a stack variable.Finding Top using top(). Function stck.top() returns reference of top element in the stckRemoving Top using pop(). Function removes topmost element from the stckAdding element to top using push(). Function stck.push( value ) adds item value in stack. Value should be of type stck.Check if staxk is ...

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Recursive Programs to find Minimum and Maximum elements of array in C++

Sunidhi Bansal
Sunidhi Bansal
Updated on 03-Nov-2021 13K+ Views

We are given an integer array Arr[] as input. The goal is to find maximum and minimum elements among the array using recursive methods.Since we are using recursion, we will traverse the whole array till we reach length=1 then return A[0] which forms the base case. Else compare current element with present minimum or maximum and update its value by recursion for later elements.Let us see various input output scenarios for this −Input − Arr= {12, 67, 99, 76, 32};Output − Maximum in the array :99Explanation − Out of all elements 99 is maximum among them.Input − Arr= {1, 0, -99, 9, 3};Output − Minimum ...

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How to add zero before a vector in R?

Nizamuddin Siddiqui
Nizamuddin Siddiqui
Updated on 03-Nov-2021 621 Views

To add zero before a vector in R, we can simply use rep function and provide the number times we want to have zero in the vector.For Example, if we have a vector called X that contains three values say 1, 2, 3 and we want to add three zeros before this vector then we can use the command as given below −X

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Fill bars in a base R barplot with colors based on frequency.

Nizamuddin Siddiqui
Nizamuddin Siddiqui
Updated on 03-Nov-2021 536 Views

Suppose we have a vector that contains only frequencies and we want to create a bar chart in base R using these frequencies with color of bars based on frequencies, therefore, we can use barplot function and providing the color of the bars with as shown in the below ExamplesThe function is as follows −heat.colors functionExample 1To fill the bars in a base R barplot with colours based on frequency, use the command given below −Frequency_1

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How to create a circle filled with a color in R?

Nizamuddin Siddiqui
Nizamuddin Siddiqui
Updated on 02-Nov-2021 1K+ Views

We can create a circle in R by using draw.circle function of plotrix package and default color of the circle is white. If we want to change the color of a circle then we can use col argument and pass the desired colors.For Example, if we want to create a blue colored circle then we can use the command given below −draw.circle(5, 5, 2, col="blue")Check out the below Example to understand how it works.ExampleTo create a circle filled with a colour, use the command given below −plot(1:10, type="n") OutputIf you execute the above command, it generates the following Output −To ...

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How to change a text value in an R data frame?

Nizamuddin Siddiqui
Nizamuddin Siddiqui
Updated on 02-Nov-2021 3K+ Views

To change a text value in an R data frame, we can simply use replace function.For Example, if we have a data frame called df that contains a column say Names and one of the names say Raj is misspelled as Raaj then we can replace Raaj with Raj by using the command given below −df$Names

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