JAVADA STRING
Javada String asosan char tipidagi qiymatlar ketma-ketligini ifodalovchi obyekt hisoblanadi. Belgili massiv esa javadagi String kabi ishlaydi, ya`ni:
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 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 qaytaradi |
4 |
static String |
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 |
Stringlarni qo’shadi |
9 |
static |
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 |
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()
Java String replace(CharSequence target, CharSequence replacement)
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()
String charAt()
Natija: t
String length()
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()
Natija:
va
vatpoint
String join()
Natija:
welcome-to-javatpoint
String equals()Natija: true false false String isEmpty()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 String concat()Natija: java string java string is immutable so assign it explicitly String replace(char old, char new)Natija: jevetpoint is e very good website String trim()Natija: hello string dasturchi hello stringdastruchi String split() 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()
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.}}
String toLowerCase()
Natija: dasturchi hello string
String toUpperCase()
Natija: HELLO STRING
G'ayratjon Rayimjonovning so'nngi maqolalari (hammasini ko'rish)
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