Programming Articles - Page 926 of 3363

Golang provides us with different approaches that we can use to print custom errors. We will explore two such approaches in this article.The first approach requires us to make use of the error.New() function which will create a new error, and we can even pass a string of our choice inside it as an argument.Example 1Consider the code shown below.package main import (    "errors"    "fmt"    "math" ) func areaOfCircle(radius float64) (float64, error) {    if radius < 0 {       return 0, errors.New("Area calculation wrong, the radius is < zero")    }   ... Read More

To find the column index of least value for each row in an R matrix, we can use apply function.For Example, if we have a matrix called M then we can find column that has the least value for each row by using the command as follows −apply(M,1,which.min)Example 1Consider the matrix given below −M1

We can make use of channels if we want to synchronize goroutines. By synchronizing, we want to make the goroutines work in a defined manner, for example, not starting the next goroutine until the previous one has finished its execution.The channels help in achieving that, as they can be used to block the process and then can also be used to notify the second goroutine that the previous goroutine has finished its job.Example 1Let's consider a very basic example of channel synchronization where we will see how we can achieve it with the help of a buffered channel.Consider the code ... Read More

Response status codes are the numbers that we get in response that signify what type of response we received from the server when we asked for something from it.There are different status codes that one gets from the response, and these are mainly divided into five categories.Generally, the status codes are divided into these five classes.1xx (Informational)2xx (Successful)3xx (Redirection)4xx (Client Error)5xx (Server Error)In this article, we will try to get two or more of these status codes.Example 1Let's start with a basic HTTP request to the google.com URL. Once we do that, we will get the response from the server ... Read More

Consider a case where we want to get the content type of a file in Golang for whatever reasons. In order to do that, we must first know how to open the file and read some of its bytes into a buffer slice which we will then pass to a function that will help us in detecting the type of the file.The first step is to open the file whose type we want to check.Open the FileConsider that we have a file named sample.pdf whose contentType is what we want to know. In order to open the file, we need ... Read More

To convert days in a week to number in R data frame column, we would need to convert the column into a factor by defining the weekdays as the levels and then read that column as integer.If we provide the correct sequence of weekdays during conversion then Monday will be converted to 1. Check out the below Examples to understand how it can be done.Example 1Following snippet creates a sample data frame −Week_Days

To delete a key from a map, we can use Go's built-in delete() function. It should be noted that when we delete a key from a map, its value will also be deleted as the key-value pair is like a single entity when it comes to maps in Go.SyntaxThe syntax of the delete function is shown below.delete(map, key)Once we call the function in the above format, then the key from the map will be deleted.Now, let's use the above function in Go code and understand how it works.Example 1Consider the code shown belowpackage main import (    "fmt" ) ... Read More

Suppose we have a JSON that looks like this.{ "name":"Mukul Latiyan", "age":10, "sports":[ "football", "tennis", "cricket" ] }Now, we want to convert this JSON into struct fields which we can access later and maybe iterate over too.In order to do that, we need to first make a struct that will satisfy the fields of the above JSON.The struct shown below will work just fine for the above JSON.type Person struct ... Read More

Be default, the boxplot created in base R or by using ggplot2 are not transparent in nature. If we want to create a transparent boxplot then we can use bwplot function from lattice package.For Example, if we have a vector called X then we can create transparent boxplot of X by using the below command −bwplot(x)Example 1To create transparent boxplot use the snippet given below −library(lattice) bwplot(rnorm(1000))OutputIf you execute the above given snippet, it generates the following Output −Example 2To create transparent boxplot add the following code to the above snippet −library(lattice) bwplot(rpois(1000, 5))OutputIf you execute all the above given ... Read More

To find the column name that has the largest value for each row in an R data frame, we can use colnames function along with apply function.For Example, if we have a data frame called df then we can find column name that has the largest value for each row by using the command as follows −df$Largest_Column