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Server Side Programming Articles
Page 1224 of 2109
Program to convert a linked list into a binary search tree in C++
Suppose we have a singly linked list where elements are arranged in non-decreasing order, we have to convert it to a height balanced binary search tree. So if the list is like [-10, -3, 0, 5, 9], The possible tree will be like −To solve this, we will follow these steps −If the list is empty, thenreturn nullDefine a recursive method called sortedListToBST() this will take list start nodex := address of the previous node of mid node from list amid := exact mid nodecreate a new node with value by taking from value of midnextStart := next of mid ...
Read MoreHow to find the column number of minimum values in each row for a data frame in R?
To find the column number of minimum values in each row for a data frame, we can use apply function but if we want to return the output in tabular form then matrix function should be used. For example, if we have a data frame df then our problem can be solved by using the code: as.matrix(apply(df, 1, which.min)).ExampleConsider the below data frame:> set.seed(37) > x1 x2 x3 x4 x5 df1 df1Outputx1 x2 x3 x4 x5 1 1 2 4 9 3 2 0 5 8 10 4 3 1 3 8 6 1 4 1 5 5 8 1 ...
Read MoreHow to add a new column to a matrix in R?
A data collection process is one of the initial and very important tasks in a data analysis project and sometimes we miss something. Therefore, we need to collect that data later and add it to the originally collected data. This mistake can be done for matrix data as well, hence we might need to add a new column to original matrix and this can be done by using cbind function.Example1> M1 M1Output [, 1] [, 2] [, 3] [, 4] [, 5] [1, ] 1 6 11 16 21 [2, ] 2 7 12 17 22 [3, ] ...
Read MoreHow to replace missing values with linear interpolation method in an R vector?
The linear interpolation is a method of fitting a curve using linear polynomials and it helps us to create a new data points but these points lie within the range of the original values for which the linear interpolation is done. Sometimes these values may go a little far from the original values but not too far. In R, if we have some missing values then na.approx function of zoo package can be used to replace the NA with linear interpolation method.Example1Loading zoo package:> library(zoo) > x1 x1Output[1] 2 2 2 5 2 2 5 NA 2 5Replacing NA with ...
Read MoreHow to create a duplicate column in an R data frame with different name?
The easiest way to create a duplicate column in an R data frame is setting the new column with $ sign and if we want to have a different name then we can simply pass a new name. For example, if we have a data frame df that contains a column x and we want to have a new column x1 having same values as in x then it can be done as df$x1 set.seed(254) > x y z a b c df dfOutputx y z a b c 1 A 0.8709244 9 0.072625990 5.125432 26.84561 2 B 1.7993156 3 ...
Read MoreHow to create a 3D-array from data frame in R?
A 3D-array is a 3-dimensional array and it is actually a collection of 2D arrays. We can create a 3D-array of a data frame in R by using simplify2array function, this function will break the data frame into arrays that will form a 3D-array.Example1Consider the below data frame:> set.seed(254) > x y z a b c df1 df1Outputx y z a b c 1 0 4 6 9 5 5 2 0 5 1 4 2 1 3 0 6 1 4 5 6 4 1 6 3 5 4 12 5 1 9 8 6 6 11 6 1 ...
Read MoreHow to generate orthogonal polynomials in R?
We can say that orthogonal is a synonym of perpendicular. If the inner product (inner product is generalization of dot product) of two polynomials is zero then we call them orthogonal polynomials. In R, we can find the orthogonal product by using poly function as shown in the below examples.Example1> x xOutput[1] 1.53798786 -0.85463326 2.39444451 0.82559418 -2.22197322 -1.04243823 [7] -0.04693054 -0.68691236 -1.63040923 -1.42408865Example> orthogonal_x orthogonal_xOutput 1 2 [1, ] 0.41743651 -0.01687537 [2, ] -0.12158589 -0.21414848 [3, ] 0.61038362 0.54027924 [4, ] ...
Read MoreHow to replace $ sign combined with some specific values in an R data frame?
Sometimes we get very dirty data and that is the reason data analysis is a difficult task. Most of the data scientists look for clean data but it is almost impossible due to data warehouses often just focus on the data availability instead of the quality of data. One of the head scratching situations is getting an unnecessary value placed at different position in a random manner, $ sign is also a that type of value. We can remove this from an R data frame by using lapply function.ExampleConsider the below data frame:> x y df1 df1Outputx y 1 C ...
Read MoreHow to create a matrix using vector generated with rep function in R?
Matrix can be only generated if we pass an even number of elements for it. If we want to create a matrix using vector generated with rep function then the length of this vector must be divisible by 2. For example, if we have a vector x that is created with rep function and it’s length is 20 then the matrix say M of size 10x2 using that vector can be constructed by using matrix(x, ncol=2).Example 1> x M1 M1Output[, 1] [, 2] [1, ] 10 10 [2, ] 4 4 [3, ] 7 7 [4, ] 3 3 [5, ...
Read MoreHow to replace missing values in a column with corresponding values in other column of an R data frame?
Often, we get missing data for analysis and we need to replace those missing values with something. Sometimes, we might want to replace them with the corresponding values in other column especially in situations when both the columns depict similar characteristics. This type of replacement can be easily done with the help of mutate function of dplyr package as shown in the below examples.Example1Consider the below data frame:> set.seed(214) > x1 x2 df1 df1Output x1 x2 1 4 75 2 8 24 3 5 38 4 4 38 5 7 NA 6 6 24 7 10 75 8 4 75 9 ...
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