arraylist in java मै हम देखगे क्या होता है arraylist क्या होता कैसे use करते है
An ArrayList is a dynamic, resizable array-like data structure that can hold elements of the same data type.
Q . what is arraylist
An ArrayList is a fundamental data structure in programming that provides a dynamic, resizable array-like container to store elements of the same data type. It is a core component in many programming languages and libraries, serving as a powerful tool for managing collections of data in various applications.
advantage of arraylist
Dynamic Size - ArrayLists can grow or shrink dynamically, allowing
for easy addition or removal of elements without manually managing the size.
Indexed Access - Elements in an ArrayList can be accessed
using an index, providing fast and efficient retrieval of elements.
Homogeneous Elements
- ArrayLists hold elements of the same data type, ensuring type safety
and consistency
Standard Library Support - Many programming languages
include ArrayList implementations in their standard libraries, making them
readily available for use without additional setup
Versatility -
ArrayLists can be used in various scenarios, such as managing lists of objects,
implementing dynamic arrays, or building stacks and queues.
Iteration and Enumeration - ArrayLists support easy iteration and enumeration through their elements using loops or iterators.
Disadvantage of arraylist
Dynamic Resizing Overhead - The dynamic resizing process of an ArrayList may incur performance overhead when the list grows large, as the underlying array needs to be expanded and elements copied to a new memory location
Inefficient Insertions/Deletions - Frequent insertions or deletions at arbitrary positions in an ArrayList can be inefficient as it may require shifting elements to maintain contiguous memory
I add a key value pair in ArrayList in Java using Map.Entry class:
import java.util.ArrayList;
import java.util.Map;
import java.util.AbstractMap.SimpleEntry;
public class Main
{
public static void main(String[] args)
{
ArrayList<Map.Entry<String, Integer>> keyValuePairs = new ArrayList<>();
// Adding key-value pairs to the ArrayList
keyValuePairs.add(new SimpleEntry<>("key1", 10));
keyValuePairs.add(new SimpleEntry<>("key2", 20));
keyValuePairs.add(new SimpleEntry<>("key3", 30));
// Accessing key-value pairs from the ArrayList
for (Map.Entry<String, Integer> entry : keyValuePairs)
{
String key = entry.getKey();
Integer value = entry.getValue();
System.out.println("Key: " + key + ", Value: " + value);
}
}
}
और भी पढ़े click करे 👇
print jumping all numbers in java
0 टिप्पणियाँ