Javada Stringlar

JAVADA STRING

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

Source code

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

Kodimiz

Source code

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 Serializable, Comparable va CharSequence interfeyslarini implement qiladi.

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.

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()

Source code

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)

Source code

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()

Source code

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()

Source code

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()

Source code

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()

Source code

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()

Source code

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()

Source code

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()

Source code

 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()

Source code    
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()Source code    
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()
Source code    
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)
Source code    
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()
Source code    
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()
Source code    
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

Source code

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()

Source code

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()

Source code

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()

Source code

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()

Source code

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

Haqida
So'nggi maqolalari

G'ayratjon Rayimjonov

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

Javada Stringlar - 14/06/2017
Javada Map - 21/03/2017
Javada Set - 26/12/2016

(3,773 marta o'qilgan, bugun 2 marta o'qildi)

O'xshash maqolalar:

4 thoughts on “Javada Stringlar”

Mo'minjon Abduraimov (MrDelphi says:

18/06/2017 at 22:49

Ajoyib maqola uchun Raxmat!

1. dasturchi.uz says:
  
  24/06/2017 at 15:17
  
  Sizga ham rahmat!
  
fury says:

15/05/2018 at 17:57

Bu darslik zo’rakan ,buni davomi bormi?

1. dasturchi.uz says:
  
  16/05/2018 at 14:11
  
  https://dasturchi.uz/programming-tutorials/javatut/4-java-dasturlash-7-gayratjon-rayimjonov/
  
  Yuqoridagi havolada siz aytgan darslik to’liq ro’yxati keltirilgan

Javada Stringlar

Java String contains()

Java String replace(CharSequence target, CharSequence replacement)

Java String equalsIgnoreCase()

Java String valueOf()

String charAt()

String length()

String format()

String substring()

String join()

G'ayratjon Rayimjonov

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

O'xshash maqolalar:

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4 thoughts on “Javada Stringlar”

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Java String contains()

Java String replace(CharSequence target, CharSequence replacement)

Java String equalsIgnoreCase()

Java String valueOf()

String charAt()

String length()

String format()

String substring()

String join()

G'ayratjon Rayimjonov

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

O'xshash maqolalar:

Do'stlaringiz bilan baham ko'ring:

Like this:

4 thoughts on “Javada Stringlar”

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