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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to convert a date to quarter and year in R?
Most of the times the date data is available only in date format and there is not information about the quarter of the year. The quarter of the year is required when we want compare the quarters or do some time series analysis. For the conversion of date into quarter and year can be done by using as.yearqtr function from zoo package as shown in the below examples.Examplelibrary(zoo) as.yearqtr("2021-01-19", format="%Y-%m-%d")Output[1] "2021 Q1"as.yearqtr("2021-04-19", format="%Y-%m-%d")[1] "2021 Q2"as.yearqtr(c("2021-04-19", "2020-05-24", "2020-11-09"), format="%Y-%m-%d")[1] "2021 Q2" "2020 Q2" "2020 Q4" Examplex1
Read MoreFind amount of water wasted after filling the tank in C++
In this tutorial, we are going to solve the following problem.Given a tank with a capacity of N liters and a pump that fill the tank with S speed per minute. Unfortunately, there is a hole in the tank. And water is wasting at a speed of WS per minute while filling it.We need to calculate the amount of water wasted for a full tank.The amount of water filled per minute is equal to the difference between the water filling water and wasting water speed.Hence we can get the total time to fill the water tank by dividing the capacity ...
Read MoreHow to create a qqplot with confidence interval in R?
A qqplot is the plot of quantiles that helps to understand whether the supplied data comes from the specified distribution, mostly it is used to check whether the data follows normal distribution or not. If we want to create the qqplot with confidence interval then qqPlot function of car package can be used as shown in the below example.Consider the below data frame −Examplex
Read MoreFind any one of the multiple repeating elements in read only array in C++
In this tutorial, we are going to write a program that finds the repeating element in the given array.Let's see the steps to solve the problem.Initialize the array.Initialize a counter map to store the frequency of each element in the array.Iterate over the array.Count each element.Print the element whose frequency is greater than 1.ExampleLet's see the code.#include using namespace std; int findRepeatingElement(int arr[], int n) { map frequencies; for (int i = 0; i < n; i++) { map::iterator itr = frequencies.find(arr[i]); if (itr != frequencies.end()) { ...
Read MoreHow to extract the residuals and predicted values from linear model in R?
The residuals are the difference between actual values and the predicted values and the predicted values are the values predicted for the actual values by the linear model. To extract the residuals and predicted values from linear model, we need to use resid and predict function with the model object.Consider the below data frame −Examplex1
Read MoreHow to change the space between bars in a barplot in R?
By default, the space between bars is equal irrespective of the number of bars in the plot. If we want to have different space between bars then space arguments need to be used inside the barplot function but the first value does not make an impact because the first space is fixed between Y-axis and the first bar. For example, if we have a vector x that contains three values then the barplot with different space between bars can be created by using the below command −barplot(x,space=c(0.5,0.1,0.5))Examplex
Read MoreHow to create a linear model with interaction term only in R?
To create a linear model with interaction term only, we can use the interaction variable while creating the model. For example, if we have a data frame called df that has two independent variables say V1 and V2 and one dependent variable Y then the linear model with interaction term only can be created as lm(Y~V1:V2,data=df).Consider the below data frame −Examplex1
Read MoreHow to find the groupwise number of positive and negative values in an R data frame?
To find the groupwise number of positive and negative values in an R data frame, we can use mutate function of dplyr package. For example, if we have a data frame called df with one categorical column x and one numerical column y then the number of positive and negative values for categorical column can be found by using the below command −df%>%group_by(x)%>%mutate(positive=sum(y>0),negative=sum(y
Read MoreHow to extract all string values from a vector in R with maximum lengths?
If we have a string vector then all the values in the vector are not likely to be of same size and we might be looking for smaller size or bigger size values. Therefore, if we want to extract all string values from a vector in R with maximum lengths even if there are duplicates can be done by using the max and nchar function as shown in the below examples.Examplex1
Read MoreHow to find mode for an R data frame column?
To find the model for an R data frame column, we can create a function and use it for the calculation. The function for mode is created as written below −mode
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