如何在字符串数组中的特定索引处追加String

Question

I have a String array like below:

String[] titles = new String[] { "Booking", "Entry", "Type",
                    "Duration", "Status", "Contract ID",
                    "Capacity", "Start Day", "End Day", "Source Ref" };

I need to append, some more values to this array at later state, like below:

titles = new String[] { "Booking", "Shipper", "Booking Quantity", "Entry", 
                        "Type", "Duration", "Status", 
                        "Contract ID", "Capacity", "Start Day", 
                        "End Day", "Source Ref" };

here I added "Shipper", "Booking Quantity" to the first array.

Is there any way to append those values based on index or any way, without creating like above example? (Is it possible?)

Answer 1

Maybe I didn't get right your question, but you can use ArrayList<String> instead of simple arrays. You can do something like this:

titles.add(1, "Shipper");
titles.add(2, "Book Quantity");

So you basically add to the ArrayList<String> of titles the two new elements at position 1 and 2.

And no, you can't do that with normal arrays.

Answer 2

when you initialize an array like this

String[] titles = new String[] { "Booking", "Entry", "Type",
                "Duration", "Status", "Contract ID",
                "Capacity", "Start Day", "End Day", "Source Ref" };

Property of array "once you initialize the array after that you can't change the size of array"*
so in your case you must initialize new array ....
Or you can use ArrayList and with its add(index, value) method you can add your value at your required position ..
But implicit it also use Concept of Dynamic Array..

Answer 3

No you can't. Arrays are not dynamic. You need to create a new array. Size must be know before creating the array.

String[] strings = new String[titles.length + 2];
strings[0] = "Booking";
strings[1] = "Shipper";
//...

Answer 4

To add them based on index you would actually need to create a new array and map all of the value from the old array and add the new values in as you go.

It would be much easier if you were using an ArrayList , which has an insert method that can insert new values at any index in the List

ex:

ArrayList<String> myList = new ArrayList<>();
myList.add("Booking");
myList.add("Entry");
myList.add("Type");
myList.add("Duration");
myList.add("Status");
myList.add("Contract ID"); 
myList.add("Capacity");
myList.add("Start Day");
myList.add("End Day");
myList.add("Source Ref");

//insertion 
myList.add(1, "Shipper");
mylist.add(2, "Booking Quantity");

Answer 5

您可以将字符串保存在ArrayList<String> ，然后使用.add(index, text)方法

Answer 6

最好使用List<String>并使用add()方法。

Answer 7

You can use ArrayList as follows:

ArrayList titleList = new ArrayList<String>();
titleList.add("Shipper");
titleList.add("Booking");
titleList.add("Entry");
titleList.add("Type");
titleList.add("Duration");
titleList.add("Status");
titleList.add("Contract");
titleList.add("ID");
//....
titleList.add(1,"Shipper")
titleList.add(2,"Booking quality");

The good thing about using ArrayList is you can use Iterator and can perform various operations like searching particular entry.