Niz je homogena zbirka sličnih vrsta elemenata koji imaju kontinuiranu memorijsku lokaciju.

Niz je vrsta podataka koju definira korisnik.

Niz je vrsta podatkovne strukture u koju spremamo elemente sličnog tipa podataka. U nizu možemo pohraniti samo fiksni skup elemenata. Možemo ga koristiti i kao objekt.

Niz je pohrana temeljena na indeksu, gdje je prvi element pohranjen na indeksu 0. Donja struktura pomaže razumjeti strukturu niza.

Karakteristike niza

1. Niz pohranjuje elemente koji imaju isti tip podataka.
2. Elementi niza pohranjeni na neprekidnim memorijskim lokacijama.
3. Pohranjivanje 2-D elemenata niza poredano je po redovima u neprekidnoj memorijskoj lokaciji.
4. Ime niza predstavlja adresu početnog elementa.
5. Veličinu niza treba inicijalizirati u trenutku deklaracije.
6. Veličina niza treba biti konstantan izraz, a ne varijabla.
7. Elemente niza možemo dohvatiti navođenjem odgovarajuće vrijednosti indeksa elementa.

Prednost

Optimizacija koda: Niz pomaže u optimiziranju koda, što povećava brzinu i performanse programa. Omogućuje nam učinkovitije dohvaćanje ili sortiranje podataka niza.

Nasumični pristup: Pruža mogućnost pristupa bilo kojem podatku niza u konstantnom vremenu (neovisno o njegovom položaju i veličini). Stoga možemo izravno dobiti bilo koji podatak niza koji se nalazi na bilo kojoj poziciji indeksa.

Hendikep

Ograničenje veličine: Niz nam omogućuje pohranjivanje samo fiksnog broja elemenata. Nakon što je polje deklarirano, ne možemo promijeniti njegovu veličinu. Dakle, ako želimo umetnuti više elementa nego što je deklarirano, to nije moguće.

Deklaracija niza

Baš kao i JavaScript, TypeScript također podržava nizove. Postoje dva načina za deklariranje niza:

1. Korištenje uglatih zagrada.

 let array_name[:datatype] = [val1,val2,valn..] 

Primjer:

 let fruits: string[] = ['Apple', 'Orange', 'Banana']; 

2. Korištenje generičkog tipa polja.

Intellij ideja protiv pomrčine

 let array_name: Array = [val1,val2,valn..] 

Primjer:

 let fruits: Array = ['Apple', 'Orange', 'Banana']; 

Vrste polja u TypeScriptu

Postoje dvije vrste niza:

1. Jednodimenzionalni niz
2. Višedimenzionalni niz

Jednodimenzionalni niz

Jednodimenzionalni niz je vrsta linearnog niza koji sadrži samo jedan red za pohranu podataka. Ima jedan skup uglatih zagrada ('[]'). Njegovim elementima možemo pristupiti pomoću indeksa retka ili stupca.

Sintaksa

 let array_name[:datatype]; 

Inicijalizacija

 array_name = [val1,val2,valn..] 

Primjer

 let arr:number[]; arr = [1, 2, 3, 4] console.log('Array[0]: ' +arr[0]); console.log('Array[1]: ' +arr[1]); 

Izlaz:

 Array[0]: 1 Array[1]: 2 

Višedimenzionalni niz

Višedimenzionalni niz je niz koji sadrži jedan ili više nizova. U višedimenzionalnom nizu podaci su pohranjeni u indeksu koji se temelji na retku i stupcu (također poznat kao matrični oblik). Dvodimenzionalni niz (2-D niz) je najjednostavniji oblik višedimenzionalnog niza.

Sintaksa

 let arr_name:datatype[][] = [ [a1,a2,a3], [b1,b2,b3] ]; 

Inicijalizacija

 let arr_name:datatype[initial_array_index][referenced_array_index] = [ [val1,val2,val 3], [v1,v2,v3]]; 

Primjer

 var mArray:number[][] = [[1,2,3],[5,6,7]] ; console.log(mArray[0][0]); console.log(mArray[0][1]); console.log(mArray[0][2]); console.log(); console.log(mArray[1][0]); console.log(mArray[1][1]); console.log(mArray[1][2]); 

Izlaz:

 1 2 3 5 6 7 

Objekt polja

Objekti polja omogućuju nam pohranjivanje više vrijednosti u jednu varijablu. Možemo stvoriti niz pomoću objekta Array. Konstruktor niza koristi se za prosljeđivanje sljedećih argumenata za stvaranje niza.

• Numerička vrijednost koja predstavlja veličinu niza ili
• Popis vrijednosti odvojenih zarezima.

Sintaksa

 let arr_name:datatype[] = new Array(values); 

Primjer

 //array by using the Array object. let arr:string[] = new Array(&apos;JavaTpoint&apos;,&apos;2200&apos;,&apos;Java&apos;,&apos;Abhishek&apos;); for(var i = 0;i <arr.length;i++) { console.log(arr[i]); } < pre> <p> <strong>Output:</strong> </p> <pre> JavaTpoint 2200 Java Abhishek </pre> <h3>Array Traversal by using a for...in loop</h3> <p> <strong>Example</strong> </p> <pre> let i:any; let arr:string[] = [&apos;JavaTpoint&apos;, &apos;2300&apos;, &apos;Java&apos;, &apos;Abhishek&apos;]; for(i in arr) { console.log(arr[i]) } </pre> <p> <strong>Output:</strong> </p> <pre> JavaTpoint 2300 Java Abhishek </pre> <h3>Passing Arrays to Functions</h3> <p>We can pass arrays to functions by specifying the array name without an index.</p> <p> <strong>Example</strong> </p> <pre> let arr:string[] = new Array(&apos;JavaTpoint&apos;, &apos;2300&apos;, &apos;Java&apos;, &apos;Abhishek&apos;); //Passing arrays in function function display(arr_values:string[]) { for(let i = 0;i <arr_values.length;i++) { console.log(arr[i]); } calling arrays in function display(arr); < pre> <p> <strong>Output:</strong> </p> <pre> JavaTpoint 2300 Java Abhishek </pre> <hr> <h2>TypeScript Spread operator</h2> <p>The spread operator is used to initialize arrays and objects from another array or object. We can also use it for object de-structuring. It is a part of the ES 6 version.</p> <p> <strong>Example</strong> </p> <pre> let arr1 = [ 1, 2, 3]; let arr2 = [ 4, 5, 6]; //Create new array from existing array let copyArray = [...arr1]; console.log(&apos;CopiedArray: &apos; +copyArray); //Create new array from existing array with more elements let newArray = [...arr1, 7, 8]; console.log(&apos;NewArray: &apos; +newArray); //Create array by merging two arrays let mergedArray = [...arr1, ...arr2]; console.log(&apos;MergedArray: &apos; +mergedArray); </pre> <p> <strong>Output:</strong> </p> <pre> CopiedArray: 1,2,3 NewArray: 1,2,3,7,8 MergedArray: 1,2,3,4,5,6 </pre> <hr> <h2>Array Methods</h2> <p>The list of array methods with their description is given below.</p> <table class="table"> <tr> <th>SN</th> <th>Method</th> <th>Description</th> </tr> <tr> <td>1.</td> <td>concat()</td> <td>It is used to joins two arrays and returns the combined result.</td> </tr> <tr> <td>2.</td> <td>copyWithin()</td> <td>It copies a sequence of an element within the array.</td> </tr> <tr> <td>3.</td> <td>every()</td> <td>It returns true if every element in the array satisfies the provided testing function.</td> </tr> <tr> <td>4.</td> <td>fill()</td> <td>It fills an array with a static value from the specified start to end index.</td> </tr> <tr> <td>5.</td> <td>indexOf()</td> <td>It returns the index of the matching element in the array, otherwise -1.</td> </tr> <tr> <td>6.</td> <td>includes()</td> <td>It is used to check whether the array contains a certain element or not.</td> </tr> <tr> <td>7.</td> <td>Join()</td> <td>It is used to joins all elements of an array into a string.</td> </tr> <tr> <td>8.</td> <td>lastIndexOf()</td> <td>It returns the last index of an element in the array.</td> </tr> <tr> <td>9.</td> <td>Pop()</td> <td>It is used to removes the last elements of the array.</td> </tr> <tr> <td>10.</td> <td>Push()</td> <td>It is used to add new elements to the array.</td> </tr> <tr> <td>11.</td> <td>reverse()</td> <td>It is used to reverse the order of an element in the array.</td> </tr> <tr> <td>12.</td> <td>Shift()</td> <td>It is used to removes and returns the first element of an array.</td> </tr> <tr> <td>13.</td> <td>slice()</td> <td>It returns the section fo an array in the new array.</td> </tr> <tr> <td>14.</td> <td>sort()</td> <td>It is used to sort the elements of an array.</td> </tr> <tr> <td>15.</td> <td>splice()</td> <td>It is used to add or remove the elements from an array.</td> </tr> <tr> <td>16.</td> <td>toString()</td> <td>It returns the string representation of an array.</td> </tr> <tr> <td>17.</td> <td>unshift()</td> <td>It is used to add one or more elements to the beginning of an array.</td> </tr> </table></arr_values.length;i++)></pre></arr.length;i++)>

Prolaz niza pomoću petlje for...in

Primjer

 let i:any; let arr:string[] = ['JavaTpoint', '2300', 'Java', 'Abhishek']; for(i in arr) { console.log(arr[i]) } 

Izlaz:

 JavaTpoint 2300 Java Abhishek 

Prosljeđivanje nizova funkcijama

Funkcijama možemo proslijediti nizove navodeći naziv niza bez indeksa.

Primjer

kako pretvoriti cijeli broj u string java

 let arr:string[] = new Array(&apos;JavaTpoint&apos;, &apos;2300&apos;, &apos;Java&apos;, &apos;Abhishek&apos;); //Passing arrays in function function display(arr_values:string[]) { for(let i = 0;i <arr_values.length;i++) { console.log(arr[i]); } calling arrays in function display(arr); < pre> <p> <strong>Output:</strong> </p> <pre> JavaTpoint 2300 Java Abhishek </pre> <hr> <h2>TypeScript Spread operator</h2> <p>The spread operator is used to initialize arrays and objects from another array or object. We can also use it for object de-structuring. It is a part of the ES 6 version.</p> <p> <strong>Example</strong> </p> <pre> let arr1 = [ 1, 2, 3]; let arr2 = [ 4, 5, 6]; //Create new array from existing array let copyArray = [...arr1]; console.log(&apos;CopiedArray: &apos; +copyArray); //Create new array from existing array with more elements let newArray = [...arr1, 7, 8]; console.log(&apos;NewArray: &apos; +newArray); //Create array by merging two arrays let mergedArray = [...arr1, ...arr2]; console.log(&apos;MergedArray: &apos; +mergedArray); </pre> <p> <strong>Output:</strong> </p> <pre> CopiedArray: 1,2,3 NewArray: 1,2,3,7,8 MergedArray: 1,2,3,4,5,6 </pre> <hr> <h2>Array Methods</h2> <p>The list of array methods with their description is given below.</p> <table class="table"> <tr> <th>SN</th> <th>Method</th> <th>Description</th> </tr> <tr> <td>1.</td> <td>concat()</td> <td>It is used to joins two arrays and returns the combined result.</td> </tr> <tr> <td>2.</td> <td>copyWithin()</td> <td>It copies a sequence of an element within the array.</td> </tr> <tr> <td>3.</td> <td>every()</td> <td>It returns true if every element in the array satisfies the provided testing function.</td> </tr> <tr> <td>4.</td> <td>fill()</td> <td>It fills an array with a static value from the specified start to end index.</td> </tr> <tr> <td>5.</td> <td>indexOf()</td> <td>It returns the index of the matching element in the array, otherwise -1.</td> </tr> <tr> <td>6.</td> <td>includes()</td> <td>It is used to check whether the array contains a certain element or not.</td> </tr> <tr> <td>7.</td> <td>Join()</td> <td>It is used to joins all elements of an array into a string.</td> </tr> <tr> <td>8.</td> <td>lastIndexOf()</td> <td>It returns the last index of an element in the array.</td> </tr> <tr> <td>9.</td> <td>Pop()</td> <td>It is used to removes the last elements of the array.</td> </tr> <tr> <td>10.</td> <td>Push()</td> <td>It is used to add new elements to the array.</td> </tr> <tr> <td>11.</td> <td>reverse()</td> <td>It is used to reverse the order of an element in the array.</td> </tr> <tr> <td>12.</td> <td>Shift()</td> <td>It is used to removes and returns the first element of an array.</td> </tr> <tr> <td>13.</td> <td>slice()</td> <td>It returns the section fo an array in the new array.</td> </tr> <tr> <td>14.</td> <td>sort()</td> <td>It is used to sort the elements of an array.</td> </tr> <tr> <td>15.</td> <td>splice()</td> <td>It is used to add or remove the elements from an array.</td> </tr> <tr> <td>16.</td> <td>toString()</td> <td>It returns the string representation of an array.</td> </tr> <tr> <td>17.</td> <td>unshift()</td> <td>It is used to add one or more elements to the beginning of an array.</td> </tr> </table></arr_values.length;i++)>

TypeScript Spread operator

Operator širenja koristi se za inicijalizaciju polja i objekata iz drugog polja ili objekta. Također ga možemo koristiti za destrukturiranje objekata. Dio je ES 6 verzije.

Primjer

 let arr1 = [ 1, 2, 3]; let arr2 = [ 4, 5, 6]; //Create new array from existing array let copyArray = [...arr1]; console.log('CopiedArray: ' +copyArray); //Create new array from existing array with more elements let newArray = [...arr1, 7, 8]; console.log('NewArray: ' +newArray); //Create array by merging two arrays let mergedArray = [...arr1, ...arr2]; console.log('MergedArray: ' +mergedArray); 

Izlaz:

 CopiedArray: 1,2,3 NewArray: 1,2,3,7,8 MergedArray: 1,2,3,4,5,6 

Metode polja

Popis metoda polja s njihovim opisom dat je u nastavku.