java

Javada Stringlar

JAVADA STRING

Javada String asosan char tipidagi qiymatlar  ketma-ketligini ifodalovchi obyekt hisoblanadi. Belgili massiv esa javadagi String kabi ishlaydi, ya`ni:

1.	char[] ch={'j','a','v','a','t','p','o','i','n','t'};  
2.	String s=new String(ch);

Kodimiz

1.	String s="javatpoint";

Kabi ishlaydi.

Java String klasi string ustida compare(), concat(), equals(), split(), length(), replace(), compareTo(), intern(), substring() kabi bir necha funksiyalarni ishlatib bir qator amallarni bajarish imkonini beradi.

java.lang.String klasi SerializableComparable va CharSequence interfeyslarini implement qiladi.

1111

CharSequence interfeysi belgilar ketma-ketligini ifodalashda ishlatiladi. U String, StringBuffer va StringBuilder klaslari tomonidan implement qilinadi. Bundan kelib chiqadiki, biz Javada stringni shu uch klasdan istalgani bilan yasay olamiz.

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String doimiydir, ya’ni uni o`zgartirib bo`lmaydi. Qachonki biz stringga o’zgartirish kiritsak, yangi instance variable – doimiy qiymat hosil qilinadi. O`zgaruvchan string uchun StringBuffer va StringBuilder klaslaridan foydalanish mumkin.

Biz o`zgarmas(immutable) stringlarga keyinroq to`xtalamiz. Avval biz javadagi string haqida to`liq ma’lumot olamiz.

No

Funksiyalar

Ta`rifi

1

char charArt(int index)

ma’lum bir index uchun char qiymat qaytaradi

2

int length()

Stringni uzuligini qaytaradi

3

static
String format(String format, Object … args)

String format qaytaradi

4

static String
format(Locale I, String format, Object …args)

Berilgan local string format qaytaradi

5

String substring(int beginIndex)

boshlang’ich index uchun

6

String substring(int beginIndex, int endIndex)

Boshlang’ich va oxirgi index uchun

7

boolean contains(CharSequence s)

Ketma ket kelgan char larnig true yoki false qiymatlarini qaytaradi

8

static String
join(CharSequence delimiter, CharSequence …elements)

Stringlarni qo’shadi

9

static
String join(CharSequence delimiter, Iterable<?
extends CharSequence> elements)

Stringlarni qo’shadi

10

boolean  equals(Object another)

String va obyektlarini tekshiradi

11

boolean isEmpty()

Stringni bo’sh ekanini tekshiradi

12

String concat(String str)

Muayyan stringlarni birlashtiradi

13

String replace(char old, char new)

Belgilangan char larni almashtiradi

14

String replace(CharSequence old, CharSequence new)

Ketma ket kelgan char’lari almashtiradi

15

String trim()

Bo’sh joyni tushirib qoldiradi

16

String split(String regex)

Stringlarni teng bo’ladi

17

String split(String regex, int limit)

Stringlarni limit bilan bo’ladi

18

String intern()

String ni biror bir qiymatda ushlab turadi

19

int indexOf(int ch)

Charlarni aniq index ‘ini qaytaradi

20

int indexOf(int ch, int fromIndex)

Charning boshlanish qiymati bilan aniq index qaytaradi

21

int indexOf(String substring)

Stringni qaysi index da turganini qaytaradi

22

int indexOf(String substring, int fromIndex)

Substring ko’rsatkichidan index o’rnini

23

String
toLowerCase()

Harflarni kichigi bilan almashtiradi

24

String toLowerCase(Locale l)

Local berilgan harflarni kichigiga almashtiradi

25

String toUpperCase()

Berilgan harflarni kattasiga almashtiradi

26

String toUpperCase(Locale l)

Local berilgan harflarni kattasiga almashtiradi

Funksiyalarga misollar

Java String contains()

1.	class ContainsExample{  
2.	    public static void main(String args[]){  
3.	       String name="what do you know about me";  
4.	       System.out.println(name.contains("do you know"));  
5.	       System.out.println(name.contains("about"));  
6.	       System.out.println(name.contains("hello"));  
7.	    }
8.	}

Java String replace(CharSequence target, CharSequence replacement)

1.	public class ReplaceExample2{  
2.	    public static void main(String args[]){  
3.	        String s1="my name is khan my name is java";  
4.	        String replaceString=s1.replace("is","was");//replaces all occurrences of "is" to "was"  
5.	        System.out.println(replaceString);  
6.	    }
7.	}

Java String equalsIgnoreCase()

1.	public class EqualsIgnoreCaseExample{  
2.	    public static void main(String args[]){  
3.	        String s1="javatpoint";  
4.	        String s2="javatpoint";  
5.	        String s3="JAVATPOINT";  
6.	        String s4="python";  
7.	        System.out.println(s1.equalsIgnoreCase(s2));//true because content and case both are same  
8.	        System.out.println(s1.equalsIgnoreCase(s3));//true because case is ignored  
9.	        System.out.println(s1.equalsIgnoreCase(s4));//false because content is not same  
10.	    }
11.	}

Java String valueOf()

1.	public class StringValueOfExample{  
2.	    public static void main(String args[]){  
3.	        int value=30;  
4.	        String s1=String.valueOf(value);  
5.	        System.out.println(s1+10);//concatenating string with 10  
6.	   }
7.	}

String charAt()

public class CharAtExample{
 public static void main(String args[]){
 String name="javatpoint";
 char ch=name.charAt(4);//to’rtinchi elementini qaytaradi
 System.out.println(ch);
 }
 }

Natija: t

String length()

public class LengthExample{
 public static void main(String args[]){
 String s1="javatpoint";
 String s2="python";
 System.out.println("string length is: "+s1.length());//javatpoint ning uzunligi 10 ga teng
 System.out.println("string length is: "+s2.length());// python uzunligi 6 ga teng
 }
 }

Natija:
string length is: 10
string length is: 6

String format()

public class FormatExample{
 public static void main(String args[]){
 String name="sonoo";
 String sf1=String.format("name is %s",name);
 String sf2=String.format("value is %f",32.33434);
 String sf3=String.format("value is %32.12f",32.33434);
 System.out.println(sf1);
 System.out.println(sf2);
 System.out.println(sf3);
}}

Natija:
name is sonoo
value is 32.334340
value is 32.334340000000

String substring()

public class SubstringExample{
public static void main(String args[]){
 String s1="javatpoint";
 System.out.println(s1.substring(2,4));//va ni qaytaradi
System.out.println(s1.substring(2));// vatpoint ni qaytaradi
 }}

Natija:
va
vatpoint

String join()

 public class StringJoinExample{
public static void main(String args[]){
 String joinString1=String.join("-","welcome","to","javatpoint");
 System.out.println(joinString1);
 }}

Natija:
welcome-to-javatpoint

String equals()

1. public class EqualsExample{
2. public static void main(String args[]){
3. String s1="javatpoint";
4. String s2="javatpoint";
5. String s3="JAVATPOINT";
6. String s4="python";
7. System.out.println(s1.equals(s2));//true
8. System.out.println(s1.equals(s3));//false
9. System.out.println(s1.equals(s4));//false
10.}}
Natija: true false false String isEmpty()
1. public class IsEmptyExample{
2. public static void main(String args[]){
3. String s1="";
4. String s2="javatpoint";
5.
6. System.out.println(s1.isEmpty());
7. System.out.println(s2.isEmpty());
8. }}
Natija: true false String concat()
1. public class ConcatExample{
2. public static void main(String args[]){
3. String s1="java string";
4. s1.concat("is immutable");
5. System.out.println(s1);
6. s1=s1.concat(" is immutable so assign it explicitly");
7. System.out.println(s1);
8. }}
Natija: java string java string is immutable so assign it explicitly String replace(char old, char new)
1. public class ReplaceExample1{
2. public static void main(String args[]){
3. String s1="javatpoint is a very good website";
4. String replaceString=s1.replace('a','e');// hamma 'a' larni 'e' ga almashtirdi
5. System.out.println(replaceString);
6. }}
Natija: jevetpoint is e very good website String trim()
1. public class StringTrimExample{
2. public static void main(String args[]){
3. String s1=" hello string ";
4. System.out.println(s1+"dasturchi");// trim() siz
5. System.out.println(s1.trim()+"dasturchi");// trim() bilan
6. }}
Natija: hello string dasturchi hello stringdastruchi String split()
1. public class SplitExample{
2. public static void main(String args[]){
3. String s1="java string split method by dasturchi";
4. String[] words=s1.split("\\s");
5. for(String w:words){
6. System.out.println(w);
7. }
8. }}
Natija: java string split method by dasturchi

String split() funksiyasi regex va length bilan

1. public class SplitExample2{
2. public static void main(String args[]){
3. String s1="welcome to split world";
4. System.out.println("returning words:");
5. for(String w:s1.split("\\s",0)){
6. System.out.println(w);
7. }
8. System.out.println("returning words:");
9. for(String w:s1.split("\\s",1)){
10.System.out.println(w);
11.}
12.System.out.println("returning words:");
13. for(String w:s1.split("\\s",2)){
14.System.out.println(w);
15.}
16.}}

Natija returning words: welcome to split world returning words:
welcome to split world returning words: welcome to split world

String intern()

1. public class InternExample{
2. public static void main(String args[]){
3. String s1=new String("hello");
4. String s2="hello";
5. String s3=s1.intern();
6. System.out.println(s1==s2);
7. System.out.println(s2==s3); 8. }}

Natija; false true
String indexOf()

1. public class IndexOfExample{
2. public static void main(String args[]){
3. String s1="this is index of example";
4. 5. int index1=s1.indexOf("is");
6. int index2=s1.indexOf("index");
7. System.out.println(index1+" "+index2);//2 8
9. int index3=s1.indexOf("is",4);
10. System.out.println(index3);
11.//passing char value
12. int index4=s1.indexOf('s');
13. System.out.println(index4);//3
14.}}
Natija: 2 8 5 3
String toLowerCase()
1. public class StringLowerExample{
2. public static void main(String args[]){
3. String s1="DASTURCHI HELLO stRIng";
4. String s1lower=s1.toLowerCase();
5. System.out.println(s1lower);
6. }}

Natija: dasturchi hello string
String toUpperCase()

1. public class StringUpperExample{
2. public static void main(String args[]){
3. String s1="hello string";
4. String s1upper=s1.toUpperCase();
5. System.out.println(s1upper); 6. }}

Natija: HELLO STRING

 

G'ayratjon Rayimjonov
G'ayratjon Rayimjonov

G'ayratjon Rayimjonovning so'nngi maqolalari (hammasini ko'rish)

(137 marta o'qilgan, bugun 1 marta o'qildi)

O'xshash maqolalar:

  • Mo’minjon Abduraimov (MrDelphi

    Ajoyib maqola uchun Raxmat!

    • dasturchi.uz

      Sizga ham rahmat!