添加字符串到一个ArrayList [英] Adding Strings to an ArrayList

问题描述

我要确保我建立这个节目的权利。我必须写一个使用一个ArrayList容器程序，并把5中的字符串，然后从ArrayList中打印出5串。我是新来ArrayList的的所以想确保我有要求的满足。

我的问题是：这是创建字符串，创建一个ArrayList，将字符串添加到列表中，然后打印列表有道

 公共静态无效的主要（字串[] args）
{ArrayList的＆LT;串GT; names_and_numbers =新的ArrayList＆LT;＆GT;（）;
字符串BOB =鲍勃;
字符串南希=南希
字符串吉姆=吉姆;
字符串克莱尔=克莱尔names_and_numbers.add（BOB）;
names_and_numbers.add（南希）;
names_and_numbers.add（JIM）;
names_and_numbers.add（克莱尔）;对（串E：names_and_numbers）
{
 的System.out.println（E）;
}诠释6 = 6;
串号=;ArrayList的＆LT;整数GT; myList中=新的ArrayList＆LT;＆GT;（）;myList.add（1）;
myList.add（2）;
myList.add（3）;
myList.add（4）;
myList.add（5）;
myList.add（SIX）;对于（INT X：myList中）
{
 的System.out.println（X）;
}//System.out.println(myList）;
//System.out.println(names_and_numbers）;
}
}
 

解决方案

您正在做的不错，我没有看到一个问题，但我认为的ArrayList存储对象，所以如果你想要一个整数，得建立一个对​​象。我想如果你能compli的是，这是自动完成的。

 整数i =新的整数（1）;
myList.add（ⅰ）;
 

或在1行

  myList.add（新的整数（1））;
 

编辑：

正如保罗Bellora说，新的整数（I）是不必要的，你可以只用替换I 。我只是想指出的ArrayList 存储对象的（不知怎的，我忘了提，），而不是基本数据类型，如 INT ，当你尝试做到这一点，将数据转换（如果可能的编译器），以对象的子就像整数。

I need to make sure I am building this program right. I have to write a program that uses an ArrayList container and put 5 Strings in it and then print out the 5 Strings from the ArrayList. I am new to ArrayList's so want to make sure I have the requirements fulfilled.

My question is: "Is this the proper way to Create Strings, Create an ArrayList, add the Strings to the List and then Print the List?"

public static void main(String[] args) 
{

ArrayList<String> names_and_numbers = new ArrayList<>();
String bob = "bob";
String nancy = "nancy";
String jim = "jim";
String claire = "claire";

names_and_numbers.add( bob ); 
names_and_numbers.add( nancy ); 
names_and_numbers.add( jim );
names_and_numbers.add( claire );      

for (String e : names_and_numbers)  
{  
 System.out.println(e);  
} 

int six = 6;
String numbers = "";

ArrayList<Integer> myList = new ArrayList<>();

myList.add( 1 ); 
myList.add( 2 ); 
myList.add( 3 );
myList.add( 4 );
myList.add( 5 );
myList.add(six);        

for (int x : myList)  
{  
 System.out.println(x);  
}     

//System.out.println(myList);   
//System.out.println(names_and_numbers);   
}
}

解决方案

You're doing ok, I don't see a question but I think that arraylists store objects, so if you want an integer, get build an object. I guess if you can compli that, this is done automatically.

Integer i = new Integer(1);
myList.add(i);

Or in 1 line

myList.add(new Integer(1));

Edit:

As Paul Bellora says, new Integer(i) is unnecessary and you can replace it with just i. I just wanted to point out that ArrayLists store objects (somehow i forgot to mention that), not primitive data types like int and when you try to do it, the data is converted if possible (to the compiler) to a child of Object just like Integer.

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