如何在 Java 中声明和初始化数组? [英] How do I declare and initialize an array in Java?

问题描述

如何在 Java 中声明和初始化数组?

How do I declare and initialize an array in Java?

推荐答案

您可以使用数组声明或数组字面量(但只有当您立即声明并影响变量时，数组字面量不能用于重新分配数组).

You can either use array declaration or array literal (but only when you declare and affect the variable right away, array literals cannot be used for re-assigning an array).

对于原始类型:

int[] myIntArray = new int[3];
int[] myIntArray = {1, 2, 3};
int[] myIntArray = new int[]{1, 2, 3};

// Since Java 8. Doc of IntStream: https://docs.oracle.com/javase/8/docs/api/java/util/stream/IntStream.html

int [] myIntArray = IntStream.range(0, 100).toArray(); // From 0 to 99
int [] myIntArray = IntStream.rangeClosed(0, 100).toArray(); // From 0 to 100
int [] myIntArray = IntStream.of(12,25,36,85,28,96,47).toArray(); // The order is preserved.
int [] myIntArray = IntStream.of(12,25,36,85,28,96,47).sorted().toArray(); // Sort 

对于类，例如String，它是一样的:

For classes, for example String, it's the same:

String[] myStringArray = new String[3];
String[] myStringArray = {"a", "b", "c"};
String[] myStringArray = new String[]{"a", "b", "c"};

当您先声明一个数组然后再初始化它、将一个数组作为函数参数传递或返回一个数组时，第三种初始化方式很有用.需要显式类型.

The third way of initializing is useful when you declare an array first and then initialize it, pass an array as a function argument, or return an array. The explicit type is required.

String[] myStringArray;
myStringArray = new String[]{"a", "b", "c"};

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