Apa HashSet?
HashSet minangka jinis data sing dibangun ing Jawa, lan kanthi istilah awam sampeyan bisa ngomong "HashSet minangka koleksi unsur unik sing ora diurutake." Deleng conto dhasar:
- Iku nggawe koleksi ( koleksi tegese unit siji saka obyek contone: ArrayList, LinkedList, Vector etc) sing nggunakake tabel hash kanggo panyimpenan.
- Nilai duplikat ora diidini ing HashSet.
- Sampeyan bisa nglebokake nilai "null" ing HashSet.
- Ora urutan selipan maintained. Dadi yen sampeyan pengin nglebokake item kanthi urut, HashSet bakal dadi pilihan sing ora becik kanggo kabutuhan sampeyan.
- Yen sampeyan pengin njaluk / njupuk unsur ing wektu pancet (O (1)) banjur HashSet iku salah siji saka pendekatan paling sampeyan bisa njupuk.
Apa metode HashSet.contains()?
HashSet.contains () minangka cara boolean kanggo mriksa yen ana item ing conto HashSet utawa ora. Cukup, manawa set kasebut ngemot unsur sing dikarepake. Java.util.HashSet nyedhiyakake implementasine sing efisien. Ayo kita nuduhake sampeyan carane sampeyan bisa nggunakake kanthi efektif kanggo ngatasi pitakon sampeyan.ngandhut () karo Integers
import java.util.HashSet;
public class HashSetDemo {
public static void main(String[] args) {
// Declare your hash set
HashSet digits = new HashSet();
digits.add(0);
digits.add(1);
digits.add(2);
digits.add(3);
digits.add(4);
digits.add(5);
digits.add(null);
System.out.println("All elements in hashset:\t" + digits);
// Try adding duplicates
digits.add(5);
digits.add(2);
System.out.println("After adding duplicates: \t" + digits);
System.out.println("\n-------Using Contains Method-------");
// Check out if the following digits exist in the hashset
System.out.println("digits.contains(0) : " + digits.contains(0));
System.out.println("digits.contains(2) : " + digits.contains(2));
System.out.println("digits.contains(3) : " + digits.contains(7));
System.out.println("digits.contains(null) : " + digits.contains(null));
}
}
Output
Kabeh unsur ing hashset: [0, null, 1, 2, 3, 4, 5] Sawise nambahake duplikat: [0, null, 1, 2, 3, 4, 5] -------Using Contains Method- ------ digits.contains(0) : true digits.contains(2) : true digits.contains(3) : false digits.contains(null) : true
ngandhut () karo Strings
Deleng conto liyane ngemot () metode karo Strings .
import java.util.HashSet;
public class HashSetDemo {
public static void main(String[] args) {
// Try working with another hash set of String type
HashSet rainbow = new HashSet();
// Adding elements into HashSet using add()
rainbow.add("Red");
rainbow.add("Orange");
rainbow.add("Yellow");
rainbow.add("Green");
rainbow.add("Blue");
rainbow.add("Indigo");
rainbow.add("Violet");
// Let's traverse the hashset
System.out.println("Traversing the rainbow:");
for (String i : rainbow){
System.out.println(i);
}
// Check out if rainbow contains this color or not
System.out.println("\n-------Using Contains Method-------");
System.out.println("rainbow.contains(\"Yellow\"): \t" + rainbow.contains("Yellow"));
System.out.println("rainbow.contains(\"White\"): \t" + rainbow.contains("White"));
System.out.println("rainbow.contains(\"Lavender\"): \t" + rainbow.contains("Lavender"));
System.out.println("rainbow.contains(\"Red\"): \t" + rainbow.contains("Red"));
// Remove a color from rainbow using remove()
rainbow.remove("Red");
// Now consume set contains() method again to check if it's still present
System.out.println("rainbow.contains(\"Red\"): \t" + rainbow.contains("Red"));
System.out.println("\nAfter removing Red: " + rainbow);
}
}
Output
Nyabrang Pelangi: Abang Violet Kuning Biru Indigo Oranye Ijo -------Migunakake Ngandhut Cara------- pelangi.ngandhut("Kuning"): bener pelangi.isi("Putih"): palsu pelangi. ngandhut("Lavender"): false rainbow.contains("Abang"): true rainbow.contains("Abang"): false Sawise mbusak Abang: [Violet, Yellow, Blue, Indigo, Orange, Green]
Nalika sampeyan bisa ndeleng urutan output beda saka urutan panggolekan unsur menyang Hashset.
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