打印出一个数组列表

Question

I have an Arraylist here:

public static void main(String[] args) {
    Person P1 = new Person("Nathen", 144.5, 55.1);
    Person P2 = new Person("Jamie", 133, 60);
    Person P3 = new Person("Tom", 134, 65);
    Person P4 = new Person("Lavi", 170, 70);

    ArrayList<String> Person = new ArrayList<String>();{
        Person.add(P1.getCategory());
        Person.add(P2.getCategory());
        Person.add(P3.getCategory());
        Person.add(P4.getCategory());
    }

    System.out.println(Person);
}

How can I get the program to print out the Arraylist one row at a time instead of the one big row I have now.

Answer 1

Use for-each loop

for(String str : Person){
    System.out.println(str);
}

Answer 2

First of all, you should follow the Java naming convention and therefore you should change the variable Person to person , or a better name since it's a list of category like categories .

Second, coming to your request, a part the loop through each item option, you have 2 others way to print it the person list out.

• You can use the Arrays.toString method by passing the corresponding array of the person list. This is how you can write it:

  System.out.println(Arrays.toString(person.toArray()));

  Output: [Nathen, Jamie, Tom, Lavi]

• In case you are using/moved to Java 8+, you can use stream. This is how you can achieve it:

  person.stream().forEach(System.out::println);

  Output:

  Nathen Jamie Tom Lavi