Java：for( String value: values）简单运用

public class Program {
    public static void main(String[] args) {

        String[] values = new String[3];
        values[0] = "Dot";
        values[1] = "Net";
        values[2] = "Perls";

        for (String value : values) {
            System.out.println(value);
        }
    }
} 

For each. This is a simple syntax form. If we loop over a collection, we use a colon, not an index variable. This enumerates each element in the collection (array, ArrayList).Array

Info: This is called a foreach-loop statement. The Java language does not support a "foreach" keyword. Please use the "for" keyword.

对于每一个。 这是一个简单的语法形式。 如果我们在一个集合上循环，我们使用冒号，而不是索引变量。 这将枚举集合中的每个元素(数组、 ArrayList)。 Array Info: 这称为 foreach 循环语句。 Java 语言不支持“ foreach”关键字。 请使用“ for”关键字

 

public class Program {

    static int count;

    static int[] getElements() {
        // Set array elements based on a static field.
        int[] array = new int[3];
        array[0] = count++;
        array[1] = count++;
        array[2] = count++;
        return array;
    }

    public static void main(String[] args) {

        // The method is called once and not many times in the for-loop.
        for (int value : getElements()) {
            System.out.println(value);
        }
    }
}
/*
output:
0 
1
2
*/

Method, for-each. A method can be called in the for-loop. This method is evaluated once and then the results of it are accessed in the loop iteration variable.

Here: This program shows that the method getElements is only called once. It is not called three times.

So: When calling a variable or method in a for-each loop, we can see that the result is cached in a local and not evaluated more than once.

方法，每个。 可以在 for 循环中调用方法。 这个方法被评估一次，然后在循环迭代变量中访问它的结果。 这里: 这个程序显示方法 getelementes 只被调用一次。 它不叫三次。 因此: 当在 for-each 循环中调用变量或方法时，我们可以看到结果被缓存在局部中，并且不会进行多次计算

 

 

来源：https://www.dotnetperls.com/for-java