将整数转换为数字数组 [英] Convert integer to array of digits

问题描述

我尝试将整数转换为数组（例如1234）到 int [] arr = {1,2,3,4};

I try to convert an integer to array for example 1234 to int[] arr = {1,2,3,4};

我写了一个函数

public static void convertInt2Array(int guess)  {
    String temp = Integer.toString(guess);
    String temp2;
    int temp3;
    int [] newGuess = new int[temp.length()];
    for(int i=0;i<=temp.length();i++) {
        if (i!=temp.length()) {
            temp2 = temp.substring(i, i+1);
        } else {
            temp2 = temp.substring(i);
            //System.out.println(i);
        }
        temp3 =  Integer.parseInt(temp2);    
        newGuess[i] = temp3;
    }
            for(int i=0;i<=newGuess.length;i++) {
                System.out.println(newGuess[i]);
            }          
}

但抛出异常：

Exception in thread "main" java.lang.NumberFormatException: For input string: ""
    at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
    at java.lang.Integer.parseInt(Integer.java:504)
    at java.lang.Integer.parseInt(Integer.java:527)
    at q4.test.convertInt2Array(test.java:28)
    at q4.test.main(test.java:14)
Java Result: 1

有任何想法吗？

推荐答案

当前问题是由于您使用< = temp.length（）而不是< temp.length（）。但是，您可以更简单地实现这一目标。即使你使用字符串方法，你也可以使用：

The immediate problem is due to you using <= temp.length() instead of < temp.length(). However, you can achieve this a lot more simply. Even if you use the string approach, you can use:

String temp = Integer.toString(guess);
int[] newGuess = new int[temp.length()];
for (int i = 0; i < temp.length(); i++)
{
    newGuess[i] = temp.charAt(i) - '0';
}

您需要进行相同的更改才能使用< ; newGuess.length <）打印出内容时 - 否则对于长度为4的数组（具有有效索引0,1,2,3），您将尝试使用 newGuess [4] 。我编写的循环的绝大多数在条件中使用< ，而不是< ; = 。

You need to make the same change to use < newGuess.length() when printing out the content too - otherwise for an array of length 4 (which has valid indexes 0, 1, 2, 3) you'll try to use newGuess[4]. The vast majority of for loops I write use < in the condition, rather than <=.

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