为Java 2维动态数组增加价值

Question

how can I possibly add a value to a 2 dimensional dynamic arrays?

String emp[][] = {
{"001","Superman","Manda","123-1233","02-14-1970","Male","Manager","20,000","Regular"},
{"002","Batman","Manda","33-1233","07-14-2007","Male","Clerk","20,000","Regular"},
};

I try this code

int arrLen = emp.lenght;
emp[arrLen][0] = "003"
emp[arrLen][1] = "Superwoman"
emp[arrLen][2] = "QC"
emp[arrLen][3] = "123-1233"
emp[arrLen][4] = "03-12-2012"
emp[arrLen][5] = "Female"
emp[arrLen][6] = "Supervisor"
emp[arrLen][7] = "10,000"
emp[arrLen][8] = "Regular"

but it doesnt work

can anyone help me?

thanks

Answer 1

You can't add to an array - after creation, the size is fixed. You should consider using a List<E> implementation such as ArrayList ... ideally having created a type to encapsulate this information better than just an array of strings. It looks like you've got dates, names, numeric values etc in there - why not use that information?

For example:

List<Person> people = new ArrayList<Person>();
people.add(new Person(1, "Superman", "Manda", new TelephoneNumber("123-1233"),
           new LocalDate(1970, 14, 2), Gender.MALE,
           "Manager", 20000, SalaryType.REGULAR);

Answer 2

You have a typo

lenght

Also, statements have to end in

;

Finally, what your actual problem is: the length of an array is fixed at creation; array[array.length] will always point outside the array.

Answer 3

Java arrays have fixed length. If you want resizable array use ArrayList .

Example:

ArrayList<String[]> list = new ArrayList<String[]>();
list.add(new String[]{"Superman","Manda","..."});
list.add(new String[]{"Superwoman","Manda","..."});

Answer 4

array.length返回一个比索引高1的数字。

Answer 5

Array objects are of fixed size. You can allocate a new, larger String[][] object and move the subarrays over to it -- ie,

String[][] tmp = new String[emp.length + 1][];
for (int i=0; i<emp.length; ++i)
   tmp[i] = emp[i];
emp = tmp;

After this, there's an empty spot at the end of your main array. Fill it with

emp[emp.length-1] = new String[] {"003", ...};

Answer 6

You have two big issues with your current code.

1) Arrays aren't dynamic, and have fixed size. You should instead use the ArrayLists data structure, where you can add values.

2) Your array.Length returns some length n, but your array is indexed from 0 to (n-1). Hence, referencing to the length, will give you an index out of bounds exception.