The range()
method in Java, part of the java.util.stream.IntStream
interface, is used to create a sequential ordered IntStream
from a start value (inclusive) to an end value (exclusive). This method is useful for generating a stream of consecutive integer values.
Table of Contents
- Introduction
range()
Method Syntax- Understanding
range()
- Examples
- Basic Usage
- Using
range()
with Other Stream Operations
- Real-World Use Case
- Conclusion
Introduction
The range()
method returns a stream consisting of the elements in the specified range. This method is particularly useful when you need to generate a stream of consecutive integers.
range() Method Syntax
The syntax for the range()
method is as follows:
static IntStream range(int startInclusive, int endExclusive)
Parameters:
startInclusive
: The inclusive initial value.endExclusive
: The exclusive upper bound.
Returns:
- A sequential
IntStream
for the range ofint
elements.
Throws:
- This method does not throw any exceptions.
Understanding range()
The range()
method generates a stream of integers starting from startInclusive
and ending at endExclusive - 1
. The generated stream is ordered and sequential.
Examples
Basic Usage
To demonstrate the basic usage of range()
, we will create an IntStream
using a range and print its elements.
Example
import java.util.stream.IntStream;
public class RangeExample {
public static void main(String[] args) {
// Create a stream from 1 to 4 (inclusive of 1, exclusive of 5)
IntStream intStream = IntStream.range(1, 5);
// Print the elements of the stream
intStream.forEach(System.out::println);
}
}
Output:
1
2
3
4
Using range()
with Other Stream Operations
This example shows how to use range()
in combination with other stream operations, such as mapping and filtering.
Example
import java.util.stream.IntStream;
public class RangeWithOtherOperationsExample {
public static void main(String[] args) {
// Create a stream from 1 to 9 (inclusive of 1, exclusive of 10)
IntStream intStream = IntStream.range(1, 10);
// Filter even numbers, map them to their squares, and print
intStream.filter(n -> n % 2 == 0)
.map(n -> n * n)
.forEach(System.out::println);
}
}
Output:
4
16
36
64
Real-World Use Case
Generating Indices for Iteration
In real-world applications, the range()
method can be used to generate indices for iteration over arrays, lists, or other data structures.
Example
import java.util.stream.IntStream;
public class GenerateIndicesExample {
public static void main(String[] args) {
String[] names = {"Alice", "Bob", "Charlie", "David"};
// Use range() to generate indices and print each name with its index
IntStream.range(0, names.length)
.forEach(i -> System.out.println("Index: " + i + ", Name: " + names[i]));
}
}
Output:
Index: 0, Name: Alice
Index: 1, Name: Bob
Index: 2, Name: Charlie
Index: 3, Name: David
Conclusion
The IntStream.range()
method is used to create a sequential ordered IntStream
from a start value (inclusive) to an end value (exclusive). This method is particularly useful for generating streams of consecutive integers. By understanding and using this method, you can efficiently generate and work with ranges of integer values in your Java applications.
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