在 Java 中将数组作为参数传递时创建数组
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Creating an array while passing it as an argument in Java
提问by Tanaki
Is there a way to create an array of objects as part of a constructor or method? I'm really not sure how to word this, so I've included an example. I have an enum, and one of the fields is an array of numbers. Here is what I tried:
有没有办法创建一个对象数组作为构造函数或方法的一部分?我真的不知道如何表达这个,所以我提供了一个例子。我有一个枚举,其中一个字段是一个数字数组。这是我尝试过的:
public enum KeyboardStuff {
QWERTY(1, {0.5f, 1.3f, 23.1f}, 6);
DVORAK(5, {0.1f, 0.2f, 4.3f, 1.1f}, 91);
CHEROKEE(2, {22.0f}, 11);
private int number, thingy;
private float[] theArray;
private KeyboardStuff(int i, float[] anArray, int j) {
// do things
}
}
The compiler says that the brackets { } are invalid and should be removed. Is there a way I can pass an array as an argument without creating an array of objects beforehand?
编译器说括号 { } 无效,应该删除。有没有一种方法可以将数组作为参数传递,而无需事先创建对象数组?
回答by Vivien Barousse
You can try with new float[] { ... }
.
您可以尝试使用new float[] { ... }
.
public enum KeyboardStuff {
QWERTY(1, new float[] {0.5f, 1.3f, 23.1f}, 6);
DVORAK(5, new float[] {0.1f, 0.2f, 4.3f, 1.1f}, 91);
CHEROKEE(2, new float[] {22.0f}, 11);
private int number, thingy;
private float[] theArray;
private KeyboardStuff(int i, float[] anArray, int j) {
// do things
}
}
回答by Peter Lawrey
Following @Dave's suggest I would use a vararg
按照@Dave 的建议,我会使用 vararg
QWERTY(1, 6, 0.5, 1.3, 23.1);
DVORAK(5, 91, 0.1, 0.2, 4.3, 1.1);
CHEROKEE(2, 11, 22.0);
private final int number, thingy;
private final double[] theArray;
private KeyboardStuff(int number, int thingy, double... theArray) {
// do things
}
It is pretty rare that using a float
is better than using a double
. double has less rounding error and only uses 4 more bytes.
使用 afloat
比使用 a 更好的情况非常罕见double
。double 具有较少的舍入误差并且仅使用了 4 个以上的字节。
回答by Dave Newton
回答by Arnout Engelen
If using Lists's instead of arrays is an option, future versions of Java might start supporting a 'collection literals' syntax which unfortunately doesn't seem to have made it into Java 8:
如果使用列表而不是数组是一种选择,那么 Java 的未来版本可能会开始支持“集合文字”语法,但不幸的是,Java 8 中似乎没有这种语法:
public enum KeyboardStuff {
QWERTY(1, [0.5f, 1.3f, 23.1f], 6);
DVORAK(5, [0.1f, 0.2f, 4.3f, 1.1f], 91);
CHEROKEE(2, [22.0f], 11);
private int number, thingy;
private List<Float> values;
private KeyboardStuff(int i, List<Float> values, int j) {
// do things
}
}