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[英]How do you return multiple values from a for loop in Java using a return statement?
[英]How do I return multiple Strings from a for loop in Java?
我使用的是for循環,每次循環都需要返回String,但是使用“ return”會中斷循環,並且Eclipse會引發“ Unreachable Code”錯誤。 有什么建議么
如果返回ArrayList<String>
,不適合您的應用程序,這聽起來像是回調函數的工作。 定義一個回調接口:
public interface StringDelivery {
public void processString(String aString);
}
然后,您可以在循環中回叫:
public void loopThroughStrings(StringDelivery callback) {
for (. . .) {
String nextString = . . .
callback.processString(nextString);
}
}
然后,您可以使用實現該接口的任何對象來調用它。
編輯:
如果要計算一堆字符串,但需要將它們作為單個字符串返回,則可以將它們放入數組中,然后使用Arrays.toString(Object[] array)
將整個數組轉換為單個String:
int n = <number of strings>
String[] strings = new String[n];
for (int i = 0; i < n; ++i) {
strings[i] = <i-th string>
}
return Arrays.toString(strings);
返回值的格式將為列表元素,並用“,”分隔並括在方括號“ []”中。
我覺得你的邏輯壞了
for (int counter = 0; counter < possibleAnswers.length; counter++){
// This condition will be meet immediately because 0 is less then 25...
if (counter < 25){
return alpha[counter] + ": " + possibleAnswers[counter] + "\n";
}
// Meaning it is impossible for the program to ever reach this line...
if (counter >= 26){
return alpha[26] + a + ": " + possibleAnswers[counter] + "\n";
a++;
}
}
我認為您最好嘗試類似...
StringBuilder sb = new StringBuilder(25);
for (int counter = 0; counter < possibleAnswers.length; counter++){
if (counter < 25){
sb.append(alpha[counter] + ": " + possibleAnswers[counter] + "\n");
}
if (counter >= 26){
sb.append(alpha[26] + a + ": " + possibleAnswers[counter] + "\n");
a++;
}
}
return sb.toString();
UPDATE工作示例
String possibleAnswers[] = new String[30];
String alpha[] = new String[30];
for (int index = 0; index < 30; index++) {
possibleAnswers[index] = "Happy " + index;
alpha[index] = Integer.toString(index);
}
int a = 0;
StringBuilder sb = new StringBuilder(25);
for (int counter = 0; counter < possibleAnswers.length; counter++) {
if (counter < 25) {
sb.append(alpha[counter]).append(": ").append(possibleAnswers[counter]).append("\n");
}
if (counter >= 26) {
sb.append(alpha[26]).append(a).append(": ").append(possibleAnswers[counter]).append("\n");
a++;
}
}
System.out.println(sb);
哪個輸出
0: Happy 0
1: Happy 1
2: Happy 2
3: Happy 3
4: Happy 4
5: Happy 5
6: Happy 6
7: Happy 7
8: Happy 8
9: Happy 9
10: Happy 10
11: Happy 11
12: Happy 12
13: Happy 13
14: Happy 14
15: Happy 15
16: Happy 16
17: Happy 17
18: Happy 18
19: Happy 19
20: Happy 20
21: Happy 21
22: Happy 22
23: Happy 23
24: Happy 24
260: Happy 26
261: Happy 27
262: Happy 28
263: Happy 29
您將要使用ArrayList來存儲所有字符串。
for循環完成后,返回ArrayList。 就像是。
String returnString = "";
for loop ....{
returnString = returnString + " " + someNewString;
}
return returnString
為什么要復雜的事情..只是返回一個字符串數組
public String[] function1()
{
String[] str1 new String(10);
for(int i=0;i<10;i++)
{
str1[i] ="string"+i;
}
return str1;
}
您應該考慮從方法返回String數組。
僅糾正for循環不會返回任何內容。 它是返回值的功能。
最后,由於不清楚您要實現的目標,因此很難評論。
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