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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to remove end lines from a boxplot in R?
The default boxplot in R has straight lines that display end point(s) excluding outliers. To remove these end lines from a boxplot, we can use staplelty argument and set it to 0.For Example, if we have a vector called X then we can create the boxplot of X by using the command given below −boxplot(X,staplelty=0)ExampleFollowing snippet creates a sample data frame −x
Read MoreHow to check if a data frame has any missing value in R?
To check if a data frame has any missing value in R, we can use any function along with is.na function. For Example, if we have a data frame called df then we can use the below command to check whether df contains any missing value or notany(is.na(df))Example 1Following snippet creates a sample data frame −x1
Read MoreHow to create pie chart in base R?
A pie chart is a circular representation of data which is created for either nominal data or ordinal data. The slices in the pie chart depend on the magnitude of the data values. If we want to create a pie chart in base R then pie function can be used.For Example, if we have a vector called X then the pie chart for values in X can be created by using the below command −pie(X)ExampleFollowing snippet creates a sample data frame −x
Read MoreHow to call a function after a delay in Kotlin?
Kotlin is based on Java, hence we can use Java-based library functions to delay a function call. In this article, we will be using a Java library function to delay the function call using Timer() and schedule().Exampleimport java.util.Timer import kotlin.concurrent.schedule fun main(args: Array) { // Execution starting point println("Hello world!!") // Delay of 5 sec Timer().schedule(5000){ //calling a function newMethod() } } fun newMethod(){ println("Delayed method call!") }OutputOnce executed, the above piece of code will yield the following output −Hello world!! Delayed method call!
Read MoreWhat's the Kotlin equivalent of Java's String[]?
String is a collection which is implemented using String class. As per the Kotlin documentation, a string can be defined as follows −Class String : Comparable, CharSequenceIn Kotlin, a string is a collection of characters. Strings are immutable in nature which means they are read-only. The length and elements of a string can be modified once declared.In Java, we have an option to create an empty String array by defining it like String[]. In this article, we will see how we can achieve the same using Kotlin library function.Example: Using arrayOf()Kotlin library provides a function to create an array of ...
Read MoreHow does the reified keyword work in Kotlin?
"reified" is a special type of keyword that helps Kotlin developers to access the information related to a class at runtime. "reified" can only be used with inline functions. When "reified" keyword is used, the compiler copies the function’s bytecode to every section of the code where the function has been called. In this way, the generic type T will be assigned to the type of the value it gets as an argument.ExampleIn this example, we will see how "reified" is helpful to re-use our code and use the same function to perform similar kind of operation regardless of its ...
Read MoreWhat is the Kotlin double-bang (!!) operator?
In Kotlin, "!!" is an operator that is known as the double-bang operator. This operator is also known as "not-null assertion operator". This operator is used to convert any value to a non-NULL type value and it throws an exception if the corresponding value is NULL. In the following example, we will see how to use this double-bang operator.Example 1In this example, we will consider a variable "name" and as a programmer, we want to throw a NULL pointer exception whenever the value of "name" is NULL. Now, execute the following codefun main(args: Array) { var name: ...
Read MoreDifference between List and Array types in Kotlin
List and array are two popular collections supported by Kotlin. By definition, both these collections allocate sequential memory location. In this article, we will take an example to demonstrate the difference between these two types of collections.AttributeArrayListImplementationArray is implemented using Array classList or MutableList interfaces are used to implement a List in KotlinMutableArray is mutable, i.e., the values can be changed.List is immutable in nature. In order to create a mutable list, MutableList interface needs to be used.SizeArray is of fixed size. It cannot increase and decrease in size.MutableList do have 'add' and 'remove' functions in order to increase or ...
Read MoreWhat are constants in Kotlin and how to create them?
In every programming language, we need some variable whose value will never change thoroughout the program. In Kotlin too, we have a keyword to create such a variable whose value will remain as constant throughout the program. In order to declare a value as constant, we can use the "const" keyword at the beginning. In this article, we will learn how we can declare a variable as constant in a different way.Example: Top level declarationExampleKotlin const variable can be declared at the top of the programming language and it can be used throughout the file scope.private const val My_TOP_LEVEL_CONST_VAL = ...
Read MoreCreate a sample of data frame column by excluding NAs in R
To create a random sample by excluding missing values of a data frame column, we can use sample function and the negation of is.na with the column of the data frame.For Example, if we have a data frame called df that contains a column X which has some NAs then we can create a random sample of size 100 of X values by using the following command −sample(df$X[!is.na(df$X)],100,replace=TRUE).Example 1Following is the code snippet to create dataframe −x
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