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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to subset columns that has less than four categories in an R data frame?
If column is categorical then there can be at least two categories and there is no limit for the total number of categories but it will also depend on the total number of cases. If we have a data frame that contain some categorical columns having more or less categories than 4 then we might want to subset columns having less than four categories. This could be required in situations when we want to subset the data biasedly or have some predefined data characteristics that allows this change. The subset of such columns can be done with the help of ...
Read MoreGolang Program to count the set bits in an integer.
ExamplesFor example, 101, 11, 11011 and 1001001 set bits count 2, 2, 4 and 3 respectively.Approach to solve this problemStep 1 − Convert number into binary representation.Step 2 − Count the number of 1s; return count.Examplepackage main import ( "fmt" "strconv" ) func NumOfSetBits(n int) int{ count := 0 for n !=0{ count += n &1 n >>= 1 } return count } func main(){ n := 20 fmt.Printf("Binary representation of %d is: %s.", n, strconv.FormatInt(int64(n), 2)) fmt.Printf("The total number of set bits in %d is %d.", n, NumOfSetBits(n)) }OutputBinary representation of 20 is: 10100. The total number of set bits in 20 is 2.
Read MoreHow to create a frequency table in data frame format in R?
To create a frequency table in R, we can simply use table function but the output of table function returns a horizontal table. If we want to read the table in data frame format then we would need to read the table as a data frame using as.data.frame function. For example, if we have a table called T then to convert it into a data frame format we can use the command as.data.frame(T).Example1> x1 x1Output[1] 2 0 2 3 2 3 1 2 1 4 0 0 4 4 1 3 1 2 1 3 2 3 2 1 4 ...
Read MoreGolang Program to find the minimum and maximum number, using binary operations.
ExamplesFor example, x = 12, y = 15 => Maximum number is 15.For example, x = 13, y = 17 => Minimum number is 13.Approach to solve this problemStep 1 − Define method, findMax and findMin, that accept two integer x and y.Step 2 − Return integer according to defined method.Examplepackage main import "fmt" func FindMax(x, y int){ fmt.Printf("Maximum element in %d, and %d is: %d", x, y, x - ((x - y) & ((x - y) >> 31))) } func FindMin(x, y int) { fmt.Printf("Minimum element in %d, and %d is: %d", x, y, y + ...
Read MoreGolang Program to round up the next highest power of 2.
ExamplesFor example, n = 12 => Next number power of 2 is 16.For example, n = 20 => Next number power of 2 is 32.Approach to solve this problemStep 1 − Define method, that accepts a number n.Step 2 − Iterate k := 1 until k < n.Step 3 − In a loop, calculate k
Read MoreGolang Program to round up the next previous power of 2.
ExamplesFor example, n = 12 => Previous number power of 2 is 8.For example, n = 20 => Previous number power of 2 is 16.Approach to solve this problemStep 1 − Define a method that accepts a number n.Step 2 − Perform n | (n >> k), where k is 1, 2, 4, 8, 16.Step 3 − At the end, return n - (n >> 1).Examplepackage main import "fmt" func PreviousPowOf2(n int) int{ n = n | (n >> 1) n = n | (n >> 2) n = n | (n >> 4) n = ...
Read MoreGolang Program to check the power of 4 of a given number
ExamplesFor example, n = 12 => 12 is not the power of 4.For example, n = 64 => 64 is the power of 4.Approach to solve this problemStep 1 − Define a method that accepts a number n.Step 2 − Divide log(n) by log(4), store in res.Step 3 − If the floor of res is same as the res, then print that n is the power of 4.Step 4 − Else, print that n is not the power of 4.Examplepackage main import ( "fmt" "math" ) func CheckPowerOf4(n int){ res := math.Log(float64(n)) / math.Log(float64(4)) if res ...
Read MoreHow to remove rows using character column that has elements of size less than 3 in an R data frame?
To find the number of characters in character vector elements or the elements in a character column of an R data frame, we can use nchar function. Therefore, if we want to remove rows that has elements of size less than 3 we would need to use the same function and then subset function will be used to remove the required rows as shown in the below examples.Example1Consider the below data frame −> x1 x2 df1 df1Output x1 x2 1 India 1 2 India 2 3 UK 1 4 UK 2 5 China 1 6 India ...
Read MoreGolang Program to find the odd-occurring elements in a given array
ExamplesFor example, arr = [1, 4, 5, 1, 4, 5, 1] => Odd-occurring element in the array is: 1Approach to solve this problemStep 1 − Define method that accepts an array.Step 2 − Declare a xor variable, i.e., xor := 0.Step 3 − Iterate input array and perform xor operation with each element of the array.Step 4 − At the end, return xor.Examplepackage main import ( "fmt" ) func FindOddOccurringElement(arr []int) int{ xor := 0 for i := 0; i < len(arr); i++ { xor = xor ^ arr[i] } return xor ...
Read MoreHow to add a new column to a data frame using mutate in R?
The mutate function of dplyr package in R can help us to add a new column to a data frame and the benefit of using mutate is that we can decide the position of the new column during the addition. For example, if we have a data frame called df that contains three columns say x, y, a then we can add a new column say z after y using mutate function. To understand how it can be done, check out the below examples.Example1Consider the below data frame −> x1 x3 df1 df1Output x1 x3 1 2 3 2 1 ...
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