将 int 数组转换为 char 数组

Question

Is it possible to cast an int array to a char array ? If so - how ?

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I'm currently working on a project where I need to create an char array containing the alphabet . My current code creats an int array (which should be converted to an char array - in one Line! ):

return IntStream.range('a', 'z' + 1).toArray();

Answer 1

Yeah, we're missing a stream method to produce a char array. Maybe a whole CharStream class. In any case, no, you cannot cast between int[] and char[] .

In the meantime, it's getting a long line, but it works:

    return IntStream.rangeClosed('a', 'z')
            .mapToObj(c -> Character.toString((char) c))
            .collect(Collectors.joining())
            .toCharArray();

This gives a char[] containing

[a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z]

Answer 2

From Java-11 and onwards , you can use .mapToObj(Character::toString) instead of .mapToObj(c -> Character.toString((char) c)) , so your overall code boils down to :

return IntStream.rangeClosed('a', 'z')
        .mapToObj(Character::toString)
        .collect(Collectors.joining())
        .toCharArray();

Answer 3

Let's keep it one line then:

return IntStream.range('a', 'z' + 1).mapToObj(i -> Character.valueOf((char) i)).toArray(Character[]::new);

This converts from IntStream , to Stream<Character> . Keep in mind chars and ints are essentially the same in terms of many calculations, so this step may be unnecessary (especially for comparisons).

Edit:

Fixed the above line to be functional, there is a better solution but I'm still trying to find it again. It currently returns a Character[] array.

Without the 1 line restriction it's simple to just remake the array, treating a as your 0 index.

char[] back = new char[('z' + 1) - 'a'];
IntStream.range('a', 'z' + 1).forEach(i -> back[i - 'a'] = (char) i);
return back;

Answer 4

You cannot cast int array to char array because there are absolutely different types.

There are 2 possible options:

1) create a char array and copy each value from int array 2) use generic lists or collections. You can simple use it for casting