Java 如何使用字符串生成器在元素之间附加双引号和“或”
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how to use string builder to append double quotes and 'OR' between elements
提问by user3467677
This is my code where I will get set of values in a list array.
这是我的代码，我将在其中获取列表数组中的一组值。
how to use string builder to append double quotes and OR between all those elements and save to a string?
如何使用字符串生成器在所有这些元素之间附加双引号和 OR 并保存到字符串？
Also is it possible to get the elements in a split? For example I will get:
也有可能在一个分裂中获得元素吗？例如我会得到：
a,b,c,d,e,f,g,h,i,j
in an array I want the output as
在一个数组中，我希望输出为
"a" OR "b" OR "c" OR "d"
and remaining elements in another iteration. As there are 10 elements I want 5 elements at at time in above format. Is it possible in string builder. Here in my example I have mentioned total as 10 elements but I actually get more than 1000 elements. Here is my code.
和另一个迭代中的剩余元素。由于有 10 个元素，我一次需要 5 个元素以上述格式。是否可以在字符串生成器中使用。在我的示例中，我提到 total 为 10 个元素，但实际上我得到了 1000 多个元素。这是我的代码。
List<String> test = new ArrayList<String>();
while (rs.next()) {
String url = rs.getString("rssUrl");
test.add(url);
}
采纳答案by Florent Bayle
Using StringBuilderis a good idea when concatenating in a loop, as it will have better performances than the simple Stringconcatenation. Here is a sample code as how to do it, using StringBuilderand modulo operation to check how many elements you want in the result:
StringBuilder在循环中连接时使用是一个好主意，因为它比简单的String连接具有更好的性能。这是一个示例代码，说明如何执行此StringBuilder操作，使用模运算来检查结果中需要多少个元素：
final int nbElems = 5;
List<String> test = new ArrayList<String>(Arrays.asList("a,b,c,d,e,f,g,h,i,j".split(",")));
StringBuilder sb = null;
for (int i=0; i<test.size(); i++) {
if (i%nbElems==0)
sb = new StringBuilder("\"");
else
sb.append("\" OR \"");
sb.append(test.get(i));
if (i%nbElems==(nbElems-1) || i==(test.size()-1)) {
sb.append("\"");
final String result = sb.toString();
System.out.println(result); // TODO: do something
}
}
Output:
输出：
"a" OR "b" OR "c" OR "d" OR "e"
"f" OR "g" OR "h" OR "i" OR "j"
回答by Roberto
This is a way to get it, there are some others:
这是一种获取方式，还有一些其他方式：
public static void main(String[] args) {
List<String> list = Arrays.asList("a","b","c","d","e","f","g","h","i","j");
StringBuilder sb = new StringBuilder(String.format("\"%s\"", list.get(0)));
for (int i = 1; i < list.size(); i++) {
sb.append(" OR ").append(String.format("\"%s\"", list.get(i)));
}
System.out.println(sb.toString());
}
The output should be:
输出应该是：
"a" OR "b" OR "c" OR "d" OR "e" OR "f" OR "g" OR "h" OR "i" OR "j"
回答by cheseaux
Here is my contribution using split and String.
这是我使用 split 和String.
String[] letters = "a,b,c,d,e,f,g,h,i,j".split(",");
String concat = "";
int index = 0;
int itemPerLine = 5;
while(index < letters.length) {
concat += "\"" + letters[index] + "\"";
index++;
if (index%itemPerLine == 0 || index==letters.length){
System.out.println(concat);
concat = "";
} else {
concat += " OR ";
}
}
As requested, it outputs :
根据要求，它输出：
"a" OR "b" OR "c" OR "d" OR "e"
"f" OR "g" OR "h" OR "i" OR "j"
回答by Autocrab
String base = "a,b,c,d,e,f,g,h,i,j";
String[] letters = base.split(",");
StringBuilder builder = new StringBuilder();
for (int i = 0; i < letters.length; i++) {
if (i > 0)
builder.append(" OR ");
builder.append("\"").append(letters[i]).append("\"");
}
