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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to remove NULL values from a list in R?
The value NULL is used to represent an object especially a list of length zero. If a list contains NULL then we might want to replace it with another value or remove it from the list if we do not have any replacement for it. To remove the NULL value from a list, we can use the negation of sapply with is.NULL.Examplesx
Read MoreCount of pairs from 1 to a and 1 to b whose sum is divisible by N in C++
We are given an integer array and the task is to count the total number of pairs (x, y) that can be formed using the given array values such that the integer value of x is less than y.Input − int a = 2, b = 3, n = 2Output − Count of pairs from 1 to a and 1 to b whose sum is divisible by N are − 3Explanation −Firstly, We will start from 1 to a which includes 1, 2 Now, we will start from 1 to b which includes 1, 2, 3 So the pairs that ...
Read MoreCount of alphabets having ASCII value less than and greater than k in C++
We are given a string of any length and the task is to calculate the count of alphabets having ASCII values less than or greater than or equals to the given integer value k.ASCII value for character A-Z are given belowABCDEFGHIJKLMNOPQRS65666768697071727374757677787980818283TUVWXYZ84858687888990ASCII value for characters a-z are given belowabcdefghijklmnopqrs979899100101102103104105106107108109110111112113114114tuvwxyz116117118119120121122Input − str = “TuTorials PoinT”, int k = 100Output −Count of alphabets having ASCII value less than k are − 6Count of alphabets having ASCII value equals or greater than k are − 9Explanation −We are given with k as 100 so we will check ASCII values of the characters in the ...
Read MoreHow to find the maximum using aggregate and get the output with all the columns in R?
When we use aggregate function to find maximum or any other value, the output of the aggregation does not provide all the columns that corresponds to the maximum value. Therefore, we need to merge the data frame obtained by using aggregate with the original data frame. In this way, we will get only those rows that are common between the new data frame and the original one.ExampleConsider the below data frame −set.seed(99) x1
Read MoreCount smaller numbers whose XOR with n produces greater value in C++
We are given an integer number let’s say, num and the task is to count the smaller numbers less than num whose XOR with num will result in a value greater than the XOR value..The truth table for XOR operation is given belowABA XOR B000101011110Input − int num = 11Output − Count of smaller numbers whose XOR with n produces greater value are − 4Explanation −We are given with the num as 11 which means we need to find XOR of num with the numbers less than num. So the numbers are 1 XOR 11 < 11(FALSE), 2 XOR 11 ...
Read MoreHow to convert two columns of an R data frame to a named vector?
If two columns are of a form such that one column contains the name of the vector values and another column having the values of a vector then we might want to convert them into a vector. To do this, we can simply read the vectors with their data type and structure them with structure function.Example 1x1
Read MoreCount smaller values whose XOR with x is greater than x in C++
We are given an integer number let’s say, x and the task are to count the smaller numbers less than x whose XOR with x will result in a value greater than the XOR value.The truth table for XOR operation is given belowABA XOR B000101011110Input − int x = 11Output − Count of smaller values whose XOR with x is greater than x are − 4Explanation −We are given with the x as 11 which means we need to find XOR of x with the numbers less than x. So the numbers are 1 XOR 11 < 11(FALSE), 2 XOR ...
Read MoreHow to collapse factor levels in an R data frame?
Sometimes the levels of a factor are not correctly recorded, for example, recording male with M in some places and with Mal in some places hence there are two levels for level male. Therefore, the number of levels increases if the factor levels are incorrectly recorded and we need to fix this issue because the analysis using these factor levels will be wrong. To convert the incorrect factor levels into the appropriate ones, we can use list function to define those levels.Example 1F
Read MoreMaximum circular subarray sum in C++
We are given an array and the task is to form the subarrays such that the sum of subarrays in a circular fashion will result in a maximum value.Input − int arr[] = {1, 2, 8, 4, 3, 0, 7}Output − Maximum circular subarray sum is − 22Explanation − we are given an array containing {1, 2, 8, 4, 3, 0, 7} and the subarray of it with maximum sum will be 7 + 1 + 2+ 8 + 4 is 22.Input − int arr[] = { 2, 5, -1, 6, 9, 4, -5 }Output − Maximum circular subarray sum ...
Read MoreHow to extract the p-value and F-statistic from aov output in R?
The analysis of variance technique helps us to identify whether there exists a significant mean difference in more than two variables or not. To detect this difference, we either use F-statistic value or p-value. If the F-statistic value is greater than the critical value of F or if p-value is less than the level of significance then we say that at least one of the means is significantly different from the rest. To extract the p-value and F-statistic value, we can make use of summary function of the ANOVA model.Exampleset.seed(123) Group
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