Masīvs ir būtiska un visbiežāk izmantotā datu struktūra Java . Tā ir viena no programmētāju visbiežāk izmantotajām datu struktūrām tās efektīvas un produktīvas īpašības dēļ; Masīvs ir līdzīgu datu tipa elementu kolekcija. Elementu glabāšanai tas izmanto blakus esošo atmiņas vietu.
Virknes masīvs ir noteikta virknes vērtību masīvs . Virkne ir rakstzīmju virkne. Parasti virkne ir nemainīgs objekts, kas nozīmē, ka virknes vērtību nevar mainīt. Virkņu masīvs darbojas līdzīgi citiem masīva datu veidiem.
In Masīvs , var saglabāt tikai fiksētu elementu kopu. Tā ir uz indeksu balstīta datu struktūra, kas sākas ar 0thpozīciju. Pirmais elements tiks rādīts indeksā 0 un 2ndelements notiks 1. rādītājā utt.
Galvenā metode {Public static void main[ String [] args]; } Java ir arī virkņu masīvs.
Apsveriet tālāk minētos punktus par virkņu masīvu:
- Tas ir masīva objekts.
- To var deklarēt ar divām metodēm; norādot izmēru vai nenorādot izmēru.
- To var inicializēt vai nu deklarēšanas laikā, vai aizpildot vērtības pēc deklarācijas.
- Elementus var pievienot virkņu masīvam pēc tā deklarēšanas.
- Virkņu masīvu var atkārtot, izmantojot for cilpu.
- Meklēšanas un kārtošanas darbību var veikt virkņu masīvā.
Deklarācija:
Masīva deklarācijai ir divi veidi, mēs varam norādīt masīva lielumu vai nenorādot masīva lielumu. Virkņu masīvu var deklarēt šādi:
String[] stringArray1 //Declaration of the String Array without specifying the size String[] stringArray2 = new String[2]; //Declarartion by specifying the size
Vēl viens masīva deklarēšanas veids ir String strArray[] , taču augstāk norādītās metodes ir efektīvākas un ieteicamākas.
Inicializācija:
Virkņu masīvu var viegli inicializēt. Tālāk ir parādīta virkņu masīva inicializācija:
1. String[] strAr1=new String[] {'Ani', 'Sam', 'Joe'}; //inline initialization 2. String[] strAr2 = {'Ani', 'Sam', ' Joe'}; 3. String[] strAr3= new String[3]; //Initialization after declaration with specific size strAr3[0]= 'Ani'; strAr3[1]= 'Sam'; strAr3[2]= 'Joe'; Visi iepriekš minētie trīs veidi tiek izmantoti, lai inicializētu virknes masīvu, un tiem ir tāda pati vērtība.
3rdmetode ir noteikta izmēra metode. Šajā indeksa vērtību var atrast, izmantojot ( masīva garums - 1 ) formulu, ja vēlamies piekļūt elementiem vairāk nekā indeksam 2 iepriekš minētajā masīvā. Tas iemetīs Java.lang.ArrayIndexOutOfBoundsException izņēmums.
Apskatīsim virkņu masīva piemēru, lai parādītu tā darbību:
Virkņu masīva iterācija
Virkņu masīvu var atkārtot, izmantojot for un foreach cilpu. Apsveriet tālāk norādīto kodu:
String[] strAr = {'Ani', 'Sam', 'Joe'}; for (int i=0; i<strar.length; i++) { system.out.println(strar[i]); } for ( string str: strar) sytem.out.println(str); < pre> <h2>Adding Elements to a String Array</h2> <p>We can easily add the elements to the String Array just like other data types. It can be done using the following three methods:</p> <ul> <tr><td>Using Pre-Allocation of the Array</td> </tr><tr><td>Using the Array List</td> </tr><tr><td>By creating a new Array</td> </tr></ul> <p>let's understand the above methods:</p> <h3>Using Pre-Allocation of the Array:</h3> <p>In this method, we already have an Array of larger size. For example, if we require to store the 10 elements, then we will create an Array of size 20. It is the easiest way to expand the Array elements.</p> <p>Consider the below example to add elements in a pre-allocated array.</p> <pre> // Java Program to add elements in a pre-allocated Array import java.util.Arrays; public class StringArrayDemo { public static void main(String[] args) { String[] sa = new String[7]; // Creating a new Array of Size 7 sa[0] = 'A'; // Adding Array elements sa[1] = 'B'; sa[2] = 'C'; sa[3] = 'D'; sa[4] = 'E'; System.out.println('Original Array Elements:' + Arrays.toString(sa)); int numberOfItems = 5; String newItem = 'F'; // Expanding Array Elements Later String newItem2 ='G'; sa[numberOfItems++] = newItem; sa[numberOfItems++] = newItem2; System.out.println('Array after adding two elements:' + Arrays.toString(sa)); } } </pre> <p> <strong>Output:</strong> </p> <pre> Original Array Elements:[A, B, C, D, E, null, null] Array after adding two elements:[A, B, C, D, E, F, G] </pre> <p>From the above example, we have added two elements in a pre-allocated Array.</p> <h3>Using ArrayList:</h3> <p>The <a href="/java-arraylist">ArrayList</a> is a fascinating data structure of the <a href="/collections-java">Java collection framework</a> . We can easily add elements to a <a href="/java-string">String</a> Array using an ArrayList as an intermediate data structure.</p> <p>Consider the below example to understand how to add elements to a String Array using ArrayList :</p> <pre> import java.util.ArrayList; import java.util.Arrays; import java.util.List; public class StringArrayDemo1 { public static void main(String[] args) { // Defining a String Array String sa[] = { 'A', 'B', 'C', 'D', 'E', 'F' }; // System.out.println('Initial Array:
' + Arrays.toString(sa)); String ne = 'G'; // Define new element to add Listl = new ArrayList( Arrays.asList(sa)); // Convert Array to ArrayList l.add(ne); // Add new element in ArrayList l sa = l.toArray(sa); // Revert Conversion from ArrayList to Array // printing the new Array System.out.println('Array with added Value:
' + Arrays.toString(sa)) ; } } </pre> <p> <strong>Output:</strong> </p> <pre> Initial Array: [A, B, C, D, E, F] Array with added value: [A, B, C, D, E, F, G] </pre> <h3>By Creating a New Array:</h3> <p>In this method, we will create a new Array with a larger size than the initial Array and accommodate the elements in it. We will copy all the elements to the newly added Array.</p> <p>Consider the below example:</p> <pre> // Java Program to add elements in a String Array by creating a new Array import java.util.Arrays; public class StringArrayDemo2 { public static void main(String[] args) { //Declaring Initial Array String[] sa = {'A', 'B', 'C' }; // Printing the Original Array System.out.println('Initial Array: ' + Arrays.toString(sa)); int length_Var = sa.length; //Defining the array length variable String newElement = 'D'; // Defining new element to add //define new array with extended length String[] newArray = new String[ length_Var + 1 ]; //Adding all the elements to initial Array for (int i=0; i <sa.length; i++) { newarray[i]="sa" [i]; } specifying the position of added elements ( last) newarray[newarray.length- 1]="newElement;" make it original and print sa="newArray;" system.out.println('updated array: ' + arrays.tostring(sa)); < pre> <p> <strong>Output:</strong> </p> <pre> Initial Array: [A, B, C] updated Array: [A, B, C, D] </pre> <p>This is how we can add elements to a String Array. Let's understand how to search and sort elements in String Array.</p> <h2>Searching in String Array</h2> <p>For searching a String from the String Array, for loop is used. Consider the below example:</p> <pre> public class StringArrayExample { public static void main(String[] args) { String[] strArray = { 'Ani', 'Sam', 'Joe' }; boolean x = false; //initializing x to false int in = 0; //declaration of index variable String s = 'Sam'; // String to be searched // Iteration of the String Array for (int i = 0; i <strarray.length; i++) { if(s.equals(strarray[i])) in="i;" x="true;" break; } if(x) system.out.println(s +' string is found at index '+in); else not the array'); < pre> <p> <strong>Output:</strong> </p> <pre> Sam String is found at index 1 </pre> <p>In the above example, we have initialized a boolean variable <strong>x</strong> to false and an index variable to iterate through the string. Also, we have declared a local variable String variable <strong>s</strong> to be searched. Here, the break keyword will exit the loop as soon as the string is found.</p> <h2>Sorting in String Array</h2> <p>The sorting in the String array is quite easy. It is performed like in a traditional array. We use a sort() method to sort the Array elements. Sorting is easier than searching.</p> <p>Consider the below example to <a href="/how-sort-string-array-java">sort a String Array</a> :</p> <pre> //Java Program to sort elements in a String Array import java.util.Arrays; public class StringArraySorting { public static void main(String[] args) { // Adding String values String[] colors = {'Cricket','Basketball','Football','Badminton','Tennis'}; // Print Original values System.out.println('Entered Sports: '+Arrays.toString(colors)); Arrays.sort(colors); // Sorting Elements // Print Sorted Values System.out.println('Sorted Sports: '+Arrays.toString(colors)); } } </pre> <p> <strong>Output:</strong> </p> <pre> Entered Sports: [Cricket, Basketball, Football, Badminton, Tennis] Sorted Sports: [Badminton, Basketball, Cricket, Football, Tennis] </pre> <p>From the above example, we can see the elements from a String Array is sorted using the sort() method.</p> <p>We can also convert String Array to other data structures such as List, int Array, ArrayList, and more and vice-versa.</p> <hr></strarray.length;></pre></sa.length;></pre></strar.length;> Izvade:
Original Array Elements:[A, B, C, D, E, null, null] Array after adding two elements:[A, B, C, D, E, F, G]
No iepriekš minētā piemēra mēs esam pievienojuši divus elementus iepriekš piešķirtam masīvam.
pavedienu sinhronizācija
Izmantojot ArrayList:
The ArrayList ir aizraujoša datu struktūra Java kolekcijas ietvars . Mēs varam viegli pievienot elementus a Stīga Masīvs, izmantojot ArrayList kā starpposma datu struktūru.
Apsveriet tālāk sniegto piemēru, lai saprastu, kā pievienot elementus virkņu masīvam, izmantojot ArrayList:
import java.util.ArrayList; import java.util.Arrays; import java.util.List; public class StringArrayDemo1 { public static void main(String[] args) { // Defining a String Array String sa[] = { 'A', 'B', 'C', 'D', 'E', 'F' }; // System.out.println('Initial Array:
' + Arrays.toString(sa)); String ne = 'G'; // Define new element to add Listl = new ArrayList( Arrays.asList(sa)); // Convert Array to ArrayList l.add(ne); // Add new element in ArrayList l sa = l.toArray(sa); // Revert Conversion from ArrayList to Array // printing the new Array System.out.println('Array with added Value:
' + Arrays.toString(sa)) ; } } Izvade:
Initial Array: [A, B, C, D, E, F] Array with added value: [A, B, C, D, E, F, G]
Izveidojot jaunu masīvu:
Izmantojot šo metodi, mēs izveidosim jaunu masīvu ar lielāku izmēru nekā sākotnējais masīvs un izvietosim tajā esošos elementus. Mēs kopēsim visus elementus tikko pievienotajā masīvā.
Apsveriet tālāk sniegto piemēru:
// Java Program to add elements in a String Array by creating a new Array import java.util.Arrays; public class StringArrayDemo2 { public static void main(String[] args) { //Declaring Initial Array String[] sa = {'A', 'B', 'C' }; // Printing the Original Array System.out.println('Initial Array: ' + Arrays.toString(sa)); int length_Var = sa.length; //Defining the array length variable String newElement = 'D'; // Defining new element to add //define new array with extended length String[] newArray = new String[ length_Var + 1 ]; //Adding all the elements to initial Array for (int i=0; i <sa.length; i++) { newarray[i]="sa" [i]; } specifying the position of added elements ( last) newarray[newarray.length- 1]="newElement;" make it original and print sa="newArray;" system.out.println(\'updated array: \' + arrays.tostring(sa)); < pre> <p> <strong>Output:</strong> </p> <pre> Initial Array: [A, B, C] updated Array: [A, B, C, D] </pre> <p>This is how we can add elements to a String Array. Let's understand how to search and sort elements in String Array.</p> <h2>Searching in String Array</h2> <p>For searching a String from the String Array, for loop is used. Consider the below example:</p> <pre> public class StringArrayExample { public static void main(String[] args) { String[] strArray = { 'Ani', 'Sam', 'Joe' }; boolean x = false; //initializing x to false int in = 0; //declaration of index variable String s = 'Sam'; // String to be searched // Iteration of the String Array for (int i = 0; i <strarray.length; i++) { if(s.equals(strarray[i])) in="i;" x="true;" break; } if(x) system.out.println(s +\' string is found at index \'+in); else not the array\'); < pre> <p> <strong>Output:</strong> </p> <pre> Sam String is found at index 1 </pre> <p>In the above example, we have initialized a boolean variable <strong>x</strong> to false and an index variable to iterate through the string. Also, we have declared a local variable String variable <strong>s</strong> to be searched. Here, the break keyword will exit the loop as soon as the string is found.</p> <h2>Sorting in String Array</h2> <p>The sorting in the String array is quite easy. It is performed like in a traditional array. We use a sort() method to sort the Array elements. Sorting is easier than searching.</p> <p>Consider the below example to <a href="/how-sort-string-array-java">sort a String Array</a> :</p> <pre> //Java Program to sort elements in a String Array import java.util.Arrays; public class StringArraySorting { public static void main(String[] args) { // Adding String values String[] colors = {'Cricket','Basketball','Football','Badminton','Tennis'}; // Print Original values System.out.println('Entered Sports: '+Arrays.toString(colors)); Arrays.sort(colors); // Sorting Elements // Print Sorted Values System.out.println('Sorted Sports: '+Arrays.toString(colors)); } } </pre> <p> <strong>Output:</strong> </p> <pre> Entered Sports: [Cricket, Basketball, Football, Badminton, Tennis] Sorted Sports: [Badminton, Basketball, Cricket, Football, Tennis] </pre> <p>From the above example, we can see the elements from a String Array is sorted using the sort() method.</p> <p>We can also convert String Array to other data structures such as List, int Array, ArrayList, and more and vice-versa.</p> <hr></strarray.length;></pre></sa.length;> Tādā veidā mēs varam pievienot elementus virkņu masīvam. Sapratīsim, kā meklēt un kārtot elementus String Array.
Meklēšana virkņu masīvā
Lai meklētu virkni no virkņu masīva, tiek izmantota cilpa for. Apsveriet tālāk sniegto piemēru:
public class StringArrayExample { public static void main(String[] args) { String[] strArray = { 'Ani', 'Sam', 'Joe' }; boolean x = false; //initializing x to false int in = 0; //declaration of index variable String s = 'Sam'; // String to be searched // Iteration of the String Array for (int i = 0; i <strarray.length; i++) { if(s.equals(strarray[i])) in="i;" x="true;" break; } if(x) system.out.println(s +\' string is found at index \'+in); else not the array\'); < pre> <p> <strong>Output:</strong> </p> <pre> Sam String is found at index 1 </pre> <p>In the above example, we have initialized a boolean variable <strong>x</strong> to false and an index variable to iterate through the string. Also, we have declared a local variable String variable <strong>s</strong> to be searched. Here, the break keyword will exit the loop as soon as the string is found.</p> <h2>Sorting in String Array</h2> <p>The sorting in the String array is quite easy. It is performed like in a traditional array. We use a sort() method to sort the Array elements. Sorting is easier than searching.</p> <p>Consider the below example to <a href="/how-sort-string-array-java">sort a String Array</a> :</p> <pre> //Java Program to sort elements in a String Array import java.util.Arrays; public class StringArraySorting { public static void main(String[] args) { // Adding String values String[] colors = {'Cricket','Basketball','Football','Badminton','Tennis'}; // Print Original values System.out.println('Entered Sports: '+Arrays.toString(colors)); Arrays.sort(colors); // Sorting Elements // Print Sorted Values System.out.println('Sorted Sports: '+Arrays.toString(colors)); } } </pre> <p> <strong>Output:</strong> </p> <pre> Entered Sports: [Cricket, Basketball, Football, Badminton, Tennis] Sorted Sports: [Badminton, Basketball, Cricket, Football, Tennis] </pre> <p>From the above example, we can see the elements from a String Array is sorted using the sort() method.</p> <p>We can also convert String Array to other data structures such as List, int Array, ArrayList, and more and vice-versa.</p> <hr></strarray.length;> Iepriekš minētajā piemērā mēs esam inicializējuši Būla mainīgo x uz false un indeksa mainīgo, kas atkārtojas virknē. Mēs esam arī deklarējuši lokālo mainīgo String mainīgais s jāmeklē. Šeit pārtraukuma atslēgvārds iziet no cilpas, tiklīdz tiks atrasta virkne.
Kārtošana virkņu masīvā
Kārtošana masīvā String ir diezgan vienkārša. Tas tiek veikts kā tradicionālajā masīvā. Masīva elementu kārtošanai mēs izmantojam metodi sort(). Kārtot ir vieglāk nekā meklēt.
Apsveriet tālāk sniegto piemēru kārtot virkņu masīvu :
//Java Program to sort elements in a String Array import java.util.Arrays; public class StringArraySorting { public static void main(String[] args) { // Adding String values String[] colors = {'Cricket','Basketball','Football','Badminton','Tennis'}; // Print Original values System.out.println('Entered Sports: '+Arrays.toString(colors)); Arrays.sort(colors); // Sorting Elements // Print Sorted Values System.out.println('Sorted Sports: '+Arrays.toString(colors)); } } Izvade:
Entered Sports: [Cricket, Basketball, Football, Badminton, Tennis] Sorted Sports: [Badminton, Basketball, Cricket, Football, Tennis]
No iepriekš minētā piemēra mēs varam redzēt, ka elementi no virknes masīvs ir sakārtoti, izmantojot metodi sort ().
Mēs varam arī pārvērst String Array uz citām datu struktūrām, piemēram, sarakstu, int Array, ArrayList un citām, un otrādi.