ArrayList of String Arrays

Question

I would like to do something like this   private ArrayList lt String   gt  addresses   new ArrayList lt String 3  gt       This does not seem to work  Whats the easiest way of storing multiple addresses with 3 fields per address in an array without creating a separate class for it

User · Answer

Simple and straight forward way to create ArrayList of String       List lt String gt  category   Arrays asList  everton    liverpool    swansea    chelsea      Cheers

User · Answer

private List lt String   gt  addresses   new ArrayList lt String   gt       this will work defenitely

User · Answer

You can t force the String arrays to have a specific size  You can do this   private List lt String   gt  addresses   new ArrayList lt String   gt       but an array of any size can be added to this list   However  as others have mentioned  the correct thing to do here is to create a separate class representing addresses  Then you would have something like   private List lt Address gt  addresses   new ArrayList lt Address gt

User · Answer

try this  ArrayList lt ArrayList lt String gt  gt  PriceModelList   new ArrayList lt  gt         ArrayList lt ArrayList lt String gt  gt  PriceQtyList   new ArrayList lt  gt         ArrayList lt ArrayList lt String gt  gt  PriceTotalList   new ArrayList lt  gt          for  int i   0  i  lt  CustomerNames length  i              PriceModelList add new ArrayList lt String gt              String   PriceModel     s6    s7    note4    note5    j5    j6            for  int j   0  j  lt  PriceModel length  j                  PriceModelList get i  add PriceModel j                       PriceQtyList add new ArrayList lt String gt              String   PriceQut     12    13    21    15    43    21            for  int k   0  k  lt  PriceQut length  k                  PriceQtyList get i  add PriceQut k                       PriceTotalList add new ArrayList lt String gt              String   PriceTotal     1323    1312321    43123212    43434    12312    43322            for  int m   0  m  lt  PriceTotal length  m                  PriceTotalList get i  add PriceTotal m                         ArrayList lt ArrayList lt ArrayList lt String gt  gt  gt  CustomersShoppingLists   new ArrayList lt  gt         CustomersShoppingLists add PriceModelList       CustomersShoppingLists add PriceQtyList       CustomersShoppingLists add PriceTotalList

User · Answer

Use a second ArrayList for the 3 strings  not a primitive array  Ie  private List lt List lt String gt  gt  addresses   new ArrayList lt List lt String gt  gt      Then you can have     ArrayList lt String gt  singleAddress   new ArrayList lt String gt     singleAddress add  17 Fake Street    singleAddress add  Phoney town    singleAddress add  Makebelieveland     addresses add singleAddress      I think some strange things can happen with type erasure here  but I don t think it should matter here   If you re dead set on using a primitive array  only a minor change is required to get your example to work  As explained in other answers  the size of the array can not be included in the declaration  So changing     private ArrayList lt String   gt  addresses   new ArrayList lt String 3  gt       to  private ArrayList lt String   gt  addresses   new ArrayList lt String   gt       will work

User · Answer

I wouldn t use arrays  They re problematic for several reasons and you can t declare it in terms of a specific array size anyway  Try   List lt List lt String gt  gt  addresses   new ArrayList lt List lt String gt  gt       But honestly for addresses  I d create a class to model them   If you were to use arrays it would be   List lt String   gt  addresses   new ArrayList lt String   gt       ie you can t declare the size of the array   Lastly  don t declare your types as concrete types in instances like this  ie for addresses   Use the interface as I ve done above  This applies to member variables  return types and parameter types

User · Answer

Following works in Java 8    List lt String   gt  addresses   new ArrayList lt  gt

User · Answer

List lt String   gt  addresses   new ArrayList lt String   gt     String   addressesArr    new String 3    addressesArr 0     zero   addressesArr 1     one   addressesArr 2     two    addresses add addressesArr

[java] ArrayList of String Arrays

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