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Programming Articles
Page 2177 of 2547
How to find the sum of values based on two groups if missing values are present in R?
To find the sum of values based on two groups if missing values are present, we can use group_by and summarise function of dplyr package.For example, if we have a data frame called df that contains a numerical column say Num and two grouping columns say Grp1 and Grp2 then, the sum of values in Num based on Grp1 and Grp2 if missing values are present in df can be found by using the below mentioned command −df%>%group_by(Grp1, Grp2)%>%summarise(Sum=sum(Num, na.rm=TRUE))Example 1Following snippet creates a sample data frame −grp1
Read MoreRearrange first N numbers to make them at K distance in C++
We are given integer variables, let's say, N and K. The task is to firstly calculate the permutation of N and then rearrange the permutation in such a manner that it will be K distance from every element.Let us see various input output scenarios for this −Input − int n = 20, int k = 2Output − Rearrangement of first N numbers to make them at K distance is: 3 4 1 2 7 8 5 6 11 12 9 10 15 16 13 14 19 20 17 18.Explanation − we are given integer variables ‘N’ i.e. 20 and ‘K’ i.e. 2. Now ...
Read MoreHow to deal with error "var(x) : Calling var(x) on a factor x is defunct." in R?
The error “Calling var(x) on a factor x is defunct” occurs when we try to apply a numerical function on factor data.For example, if we have a factor column in a data frame then applying numerical functions on that column would result in the above error. To deal with this problem, we can use as.numeric function along with the numerical function as shown in the below examples.Example 1Following snippet creates a sample data frame −x
Read MoreRearrange positive and negative numbers with constant extra space in C++
We are given an integer type array containing both positive and negative numbers, let's say, arr[] of any given size. The task is to rearrange an array in such a manner that all the elements of an array are sorted using the inbuilt sort function of C++ STL as well as using recursive technique of coding and printing the result.Let us see various input output scenarios for this −Input − int arr[] = {4, 2, -1, -1, 6, -3, 0}Output − Rearrangement of positive and negative numbers with constant extra space is: -3 -1 -1 0 6 2 4.Explanation − we are given ...
Read MoreRearrange positive and negative numbers using inbuilt sort function in C++
We are given an integer type array containing both positive and negative numbers, let's say, arr[] of any given size. The task is to rearrange an array in such a manner that all the elements of an array are sorted using the inbuilt sort function of C++ STL as well as using recursive technique of coding and printing the result.Let us see various input output scenarios for this −Input − int arr[] = {4, 2, -1, -1, 6, -3, 0}Output − Rearrangement of positive and negative numbers using inbuilt sort function is: -3 -1 -1 0 2 4 6.Explanation − we are given ...
Read MoreRoll up R data frame columns for summation by group if missing values exist in the data frame.
The summation of column values if missing values exist in the R data frame can be found with the help of summarise_each function of dplyr package where we can remove missing values by setting na.rm argument to TRUE.Since, we we will have groups in the data frame hence group_by function of the same package will help the summarise_each function to perform the summation by group. Check out the below Examples to understand how it works.Example 1Following snippet creates a sample data frame −Grp
Read MoreRearrange positive and negative numbers in O(n) time and O(1) extra space in C++
We are given an integer type array containing both positive and negative numbers, let's say, arr[] of any given size. The task is to rearrange an array in such a manner that all positive and negative numbers should be at alternate positions and if there are extra positive or negative elements then they will be placed in the end of an array.Let us see various input output scenarios for this −Input − int arr[] = {4, 2, -1, -1, 6, -3}Output − Rearrangement of positive and negative numbers in O(n) time and O(1) extra space is: 2 - 1 6 -1 4 ...
Read MoreRearrange array such that even positioned are greater than odd in C++
We are given an integer type array containing both positive and negative numbers, let's say, arr[] of any given size. The task is to rearrange an array in such a manner that all the elements at an even position or index should be greater than the elements at an odd position or index and print the result.Let us see various input output scenarios for this −Input − int arr[] = {2, 1, 4, 3, 6, 5, 8, 7}Output − Array before Arrangement: 2 1 4 3 6 5 8 7 Rearrangement of an array such that even positioned are greater than odd ...
Read MoreRearrange array such that even index elements are smaller and odd index elements are greater in C++
We are given an integer type array containing both positive and negative numbers, let's say, arr[] of any given size. The task is to rearrange an array in such a manner that all the elements at an even position or index should be less than the elements at an odd position or index and print the result.Let us see various input output scenarios for this −Input − int arr[] = {2, 1, 4, 3, 6, 5, 8, 7}Output − Array before Arrangement: 2 1 4 3 6 5 8 7 Rearrangement of an array such that even index elements are smaller and ...
Read MoreRearrange array in alternating positive & negative items with O(1) extra space in C++
We are given an integer type array containing both positive and negative numbers, let's say, arr[] of any given size. The task is to rearrange an array in such a manner that there will be a positive number that will be surrounded by negative numbers. If there are more positive and negative numbers, then they will be arranged at the end of an array.Let us see various input output scenarios for this −Input − int arr[] = {-1, -2, -3, 1, 2, 3}Output − Array before Arrangement: -1 -2 -3 1 2 3 Rearrangement of an array in alternating positive & negative ...
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