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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to create a step histogram using ggplot2 in R?
To create a step histogram using ggplot2, we can use geom="step" argument inside stat_bin function. For example, if we have a data frame that contains a single column then the step histogram can be created using the command − ggplot(df,aes(x))+stat_bin(geom="step",bins=30)Examplelibrary(ggplot2) ggplot(df,aes(x))+stat_bin(geom="step",bins=30)Output
Read MoreHow to display star for significance in base R boxplot?
To display the star for significance in a base R boxplot, we can use text function. The text function will be helpful in defining the star sign (that is asterisk or *). If the significance is high then three stars are used and the significance is low then a single star is used. We need to use the appropriate position using x and y values.Exampletext(x=1,y=max(df$y[df$x==1]),"***",pos=3,cex=1.5)Output
Read MoreHow to divide the data frame rows in R by row standard deviation?
To divide the data frame row values by row standard deviation in R, we can follow the below steps −First of all, create a data frame.Then, use apply function to divide the data frame row values by row standard deviation.Creating the data frameLet's create a data frame as shown below −> x y df dfOn executing, the above script generates the below output(this output will vary on your system due to randomization) − x y 1 1.48 0.86 2 -0.14 -0.58 3 -0.25 1.22 4 0.18 0.25 5 0.50 0.68 6 -1.34 -0.21 ...
Read MoreWhy do we need generics in Java?
Reference typesAs we know a class is a blue print in which we define the required behaviors and properties and, an interface is similar to class but it is a Specification (containing abstract methods).These are also considered as datatypes in Java, unlike other primitive datatypes a literal of these kind of types points/refers to the location of the object. They are also known as reference types.GenericsGenerics is a concept in Java where you can enable a class, interface and, method, accept all (reference) types as parameters. In other words it is the concept which enables the users to choose the ...
Read MoreHow to extract the factor levels from factor column in an R data frame?
To extract the factor levels from factor column, we can simply use levels function. For example, if we have a data frame called df that contains a factor column defined with x then the levels of factor levels in x can be extracted by using the command levels(df$x). This extraction is helpful if we have a large number of levels.Example1x2
Read MoreHow to create bar chart based on two groups in an R data frame?
To create a bar chart based on two groups, we can use geom_bar function of ggplot2 package with position argument that defines the position of the groups. For example, if we have a data frame called df that contains two categorical variable x1 and x2 and the one response variable y then the bar chart can be created by using the below command −ggplot(df,aes(x1,y,fill=x2))+geom_bar(position=position_dodge(),stat="identity")Examplelibrary(ggplot2) ggplot(df,aes(Age_Group,Y,fill=Gender))+geom_bar(position=position_dodge(),stat="identity")Output
Read MoreJava Program to Check if a String is Numeric
ExampleYou can check if a given string is Numeric as shown in the following program.import java.util.Scanner; public class StringNumeric { public static void main(String[] args) { Scanner sc = new Scanner(System.in); System.out.println("Enter a string ::"); String str = sc.next(); boolean number = str.matches("-?\d+(\.\d+)?"); if(number) { System.out.println("Given string is a number"); } else { System.out.println("Given string is not a number"); } } }OutputEnter a string :: 4245 Given string is a number
Read MoreJava Program to Convert a Stack Trace to a String
The Java.io.StringWriter class is a character stream that collects its output in a string buffer, which can then be used to construct a string. Closing a StringWriter has no effect.The Java.io.PrintWriter class prints formatted representations of objects to a text-output stream.Using these two classes you can convert a Stack Trace to a String.Exampleimport java.io.PrintWriter; import java.io.StringWriter; public class StackTraceToString { public static void main(String args[]) { try { int a[] = new int[2]; System.out.println("Access element three :" + a[3]); } catch (ArrayIndexOutOfBoundsException e) { ...
Read MoreHow to use the Glyphicons icons in Bootstrap
To use the Glyphicons icon in Bootstrap, use the following code just about anywhere in your code. Leave a space between the icon and text for proper padding like −Example Bootstrap Example You can try to run the following code to implement the Glyphicons icons:Example Bootstrap Example The following are the icons:
Read MoreHow to split a Java String into tokens with StringTokenizer?
The hasMoreTokens() method is used to test if there are more tokens available from this tokenizer's string.Exampleimport java.util.*; public class StringTokenizerDemo { public static void main(String[] args) { // creating string tokenizer StringTokenizer st = new StringTokenizer("Come to learn"); // checking elements while (st.hasMoreElements()) { System.out.println("Next element : " + st.nextElement()); } } }OutputNext element : Come Next element : to Next element : learn
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