如何遍歷數組列表並使用for循環每X次執行一次操作？ Java

Question

我想通過由解析HTML行組成的字符串的ArrayList迭代。如何使用double for循環打印0-353，同時每4個打印一行？感謝所有幫助

我必須做的是去每一行，檢查它是否是世界，國家，成員或活動。我會將所有4個數據添加到一個對象中，每次完成填充對象時，我都必須開始一個新對象以添加到另一個對象的數組列表中。

<a id='slu-world-301' class='server-list__world-link'  href='http://oldschool.runescape.com/game?world=301'>Old School 1</a> 
<td class='server-list__row-cell server-list__row-cell--country server-list__row-cell--US'>United States</td> 
<td class='server-list__row-cell server-list__row-cell--type'>Free</td> 
<td class='server-list__row-cell'>Trade - Free</td> 
<a id='slu-world-302' class='server-list__world-link' href='http://oldschool.runescape.com/game?world=302'>Old School 2</a> 
<td class='server-list__row-cell server-list__row-cell--country server-list__row-cell--GB'>United Kingdom</td> 
<td class='server-list__row-cell server-list__row-cell--type'>Members</td> 
<td class='server-list__row-cell'>Trade - Members</td> 
<a id='slu-world-303' class='server-list__world-link' href='http://oldschool.runescape.com/game?world=303'>Old School 3</a> 
<td class='server-list__row-cell server-list__row-cell--country server-list__row-cell--DE'>Germany</td> 
<td class='server-list__row-cell server-list__row-cell--type'>Members</td> 
<td class='server-list__row-cell'>-</td> 

我當前的代碼：

for(int i=1;i<(strs.size()/4) + 1;i++){ 
    for(int j=0;j<4;j++){ 
     System.out.println(???? WHAT DO I PUT HERE ????) 
    } 
     System.out.println("-----------------"); 
} 

Answer 1

我建議使用此％餘運營商
參考https://docs.oracle.com/javase/tutorial/java/nutsandbolts/op1.html

0 % 4 = 0 
1 % 4 = 1 
2 % 4 = 2 
3 % 4 = 3 
4 % 4 = 0 



for(int i = 0; i < strs.size(); i++){ 
    System.out.println(i); 
    if (i%4 == 3) { 
     System.out.println("---------"); 
    } 
} 

輸出

0 
1 
2 
3 
--------- 
4 
5 
6 
7 
--------- 
8 
9 
10 
11 
--------- 

---

如果代碼如下

for(int i=0;i<strs.size();i++) { 
    if(i%4 ==0) { 
     System.out.println("---------"); 
    } 
    System.out.println(i); 
} 

輸出將是

------------ //will more one ----- because 0 % 4 = 0 
0 
1 
2 
3 
------------ 
4 
5 
6 
7 
------------ 
8 
9 

---

Answer 2

它打印我們唯一的0-351是

i<(strs.size()/4) 

因爲strs.size() = 354或353（從評論），您的外環變得

原因

for(int i=0;i< 88;i++) 

，因此您可以達到最大值87*4 + 3 =>351。

---

您可以更改爲迭代：

for(int i=0;i<strs.size();i++) { 
    if(i%4 ==0) { 
     System.out.println("---------"); 
    } 
    System.out.println(i); 
}