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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to check whether a column exists in an R data frame?
If we have very large data set then it is highly that we forget the column names, therefore, we might want to check whether a particular column exists in the data frame or not if we know the column name. For this purpose, we can use grep function that will result the column name if exists in the data frame otherwise 0. To understand how it works check out the below examples.Example1ID
Read MoreHow to change the name of variables in a list in R?
The name of variables in a list are actually the list elements. These elements can be either named or unnamed. The naming can be done with the help of names function and renaming can be done in the same way as well. For example, if we have a list called LIST then the names of the element in LIST can be done by using the below command: names(LIST)
Read MoreWrite a Golang program to find pairs with the given sum in an array(O(n))
ExamplesInput Array = [1, 3, 5, 7, 8, 9], sum = 11 => (3, 8)Approach to solve this problemStep 1: Define a method that accepts an array and sum.Step 2: Define a mapping variable, type map[int]int.Step 3: Iterate the given array as i.Step 4: If key in mapping sum-arr[i] is not present, then mapping[arr[i]]=i.Step 5: If present, then print “pair is found”.Step 6: At the end, print that “pair not found”.Programpackage main import "fmt" func findSumPair(arr []int, sum int){ mapping := make(map[int]int) for i:=0; i
Read MoreWrite a Golang program to sort a binary array in linear time
There are two methods in which we can solve this problem. Let’s check the first method.Method 1ExamplesInput Array = [1, 0, 1, 0, 1, 0, 0, 1] => [0, 0, 0, 0, 1, 1, 1, 1]Approach to solve this problemStep 1: Define a method that accepts an array.Step 2: Count number of 0.Step 3: Store 0 till count becomes 0 and store 1 at the remaining indexes.Step 4: At the end, return the array.Programpackage main import "fmt" func binarySort(arr []int) []int{ count := 0 for i:=0; i
Read MoreHow to find the sum of squared deviations for an R data frame column?
The sum of squared deviations is the total of the square of difference between each value and the mean. To find this value, we need to create the formula in R platform. For example, if we have a data frame called df that contains a column x then the sum of squared deviations for x can be calculated by using sum((df$x−mean(df$x))^2).Example1y1
Read MoreHow to find the correlation of one variable with all the other variables in R?
To find the correlation of each variable with remaining variables, we can create a correlation matrix but for the correlation of only one variable with all the other variables we need to define the columns inside the cor function. The output will represent the columns and rows as passed inside the function.Example1y1
Read MoreWrite a Golang program to find duplicate elements in a given array
ExamplesInput Array = [1, 3, 5, 6, 1] => Duplicate element is 1;Input Array = [1, 3, 5, 6, 7] => return -1Approach to solve this problemStep 1: Define a method that accepts an array.Step 2: Declare a visited map.Step 3: Iterate the given array. If the element exists in the visited map, then return that element.Step 4: Else, return -1.Programpackage main import "fmt" func duplicateInArray(arr []int) int{ visited := make(map[int]bool, 0) for i:=0; i
Read MoreHow to create a frequency table in R that includes zero frequency for value that are not available?
When we use table function in R, the output shows the frequency of values that are available in the vector or in column of the data frame. If we want to create the table with the frequency zero for values that are not part of the vector or the column then first we need to convert them to factor first and then use the table function.Example1x1
Read MoreWrite a Golang program to find duplicate elements in a given range
We can solve this problem in two different ways. Let’s check the first method.Method 1: ExamplesInput Array = [1, 2, 3, 4, 4] => Range is from 1 to 5 but 4 is a duplicate element in this range.Approach to solve this problemStep 1: Define a method that accepts an array.Step 2: Declare a visited map.Step 3: Iterate the given array. If the element exists in the visited map, then return that element.Step 4: Else, return -1.Programpackage main import "fmt" func duplicateInArray(arr []int) int{ visited := make(map[int]bool, 0) for i:=0; i Range is from 1 to 5 but 4 is ...
Read MoreHow to create a column with largest size string value in rows in an R data frame?
To create a column with largest size string value in rows, we can use apply function and define the size of the string for the largest value by creating a function as shown in the below examples. If the number of characters in all the columns are same or there exists some ties then the output will be the first one.Example1y1
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