java - Page 3 of 3 - The code examples

How to repeat string n times in java?

August 27, 2017January 2, 2021 - by Tirex - Leave a Comment

Suppose you have the string ‘qwe’ and you need to repeat string ‘n’ times. Here’s how to do it: Using java 8 stream api

String newString = Collections.nCopies(3, "qwe").stream().collect(Collectors.joining("")); 

String newString = Stream.generate(() -> "qwe").limit(3).collect(Collectors.joining());

String newString = String.join("", Collections.nCopies(n, s));

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String newString = Collections.nCopies(3, "qwe").stream().collect(Collectors.joining(""));

String newString = Stream.generate(() -> "qwe").limit(3).collect(Collectors.joining());

String newString = String.join("", Collections.nCopies(n, s));

Using String.format

String s = "qwe";
int n = 3;
//this line print 'qweqweqwe'
String newString = String.format("%0" + n + "d", 0).replace("0", s);

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String s = "qwe";

int n = 3;

//this line print 'qweqweqwe'

String newString = String.format("%0" + n + "d", 0).replace("0", s);

Let us examine …

java

How to convert ‘ArrayList to String array in Java

August 26, 2017November 27, 2017 - by Tirex - Leave a Comment

Using Collection.toArray method First way to convert arraylist is to use built-in for every java collection method toArray(T[] ts) For example:

List<String> animals = new ArrayList<String>();
//add some elements
animals.add("cat");
animals.add("dog");
String[] stringArray = animals.toArray(new String[0]);
System.out.println(Arrays.toString(stringArray));

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List<String> animals = new ArrayList<String>();

//add some elements

animals.add("cat");

animals.add("dog");

String[] stringArray = animals.toArray(new String[0]);

System.out.println(Arrays.toString(stringArray));

The toArray() method without any argument returns Object[]. So you have …

java

How to compare strings in Java?

August 26, 2017February 10, 2018 - by Tirex - Leave a Comment

Test strings equality == tests object references, .equals() tests the string values. Sometimes it looks as if == compares values, because Java does some behind-the-scenes stuff to make sure identical …

java

How to convert a String to an int in Java?

August 25, 2017August 26, 2017 - by Tirex - Leave a Comment

You can use built-in methods:

java

JShell – Java 9 interpreter (REPL) – Getting Started

August 21, 2017November 17, 2017 - by Tirex - Leave a Comment

What is REPL Many languages include tools (sometimes called REPL) for statements interpretation. Using these tools you can test code snippets quickly without creating full project. For example python. Creating …

java