[英]Conversion of Integer Arraylist to string
I'm trying to convert the numbers of my Array list into Strings at point i. 我正在尝试在点i将数组列表的数字转换为字符串。 How do I do this so I can create substrings of my numbers?
我该怎么做才能创建数字的子字符串?
ArrayList<Integer> numbers= new ArrayList<Integer>();
for( int i=0; i<=10; i++){
String numbersString[i] = String.valueOf(numbers[i]);
}
If numbers[i]
is of type Integer
you can just use its built in toString()
method. 如果
numbers[i]
的类型为Integer
,则可以使用其内置的toString()
方法。 However, as numbers
is an ArrayList
, you need to use numbers.get(i)
. 但是,由于
numbers
是ArrayList
,因此需要使用numbers.get(i)
。
String numbersString[i] = ...
is invalid syntax. String numbersString[i] = ...
是无效的语法。 You have to declare your array outside the loop and then access it simply by numbersString[i] = ...
inside the loop. 您必须在循环外部声明数组,然后在循环内部仅通过
numbersString[i] = ...
对其进行访问。
I would suggest something like this. 我建议这样。
StringBuilder sb = new StringBuilder();
for (Integer number : numbers) {
sb.append(number != null ? number.toString() : "");
}
System.out.println("The number string = " + sb.toString());
Looking your code you need a input of ArrayList and output of String[]. 查看您的代码,您需要ArrayList的输入和String []的输出。
You can use Collections2 of Guava lib to transform to string and after parse to array. 您可以使用Guava lib的Collections2转换为字符串,然后解析为数组。
ArrayList<Integer> numbers = new ArrayList<Integer>();
Collection<String> transform = Collections2.transform(numbers, new Function<Integer, String>() {
@Override
@Nullable
public String apply(@Nullable Integer input) {
return input.toString();
}
});
final String[] array = transform.toArray(new String[transform.size()]);
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