当我打印出arraylist的索引时如何删除最后一个逗号

Question

List<String> list1 = new ArrayList<String>(words.length);
List<String> list2 = new ArrayList<String>(word.length);    
for(String x: list1){
        for(String y: list2){
            if(x.equalsIgnoreCase(y)){
               System.out.print(list1.indexOf(x) +" "+ ",");
            }
        }
    }

对于此函数，运行后，输出将为2,5,7 .... 9，我的问题是如何删除最后一个逗号？

Answer 1

我会在一开始打印逗号，像这样-

boolean first = true;
for(String x: list1){
    for(String y: list2){
        if(x.equalsIgnoreCase(y)){
           if (first) {
               first = false;
           } else {
               System.out.print(", "); // <-- or " ," if you prefer.
           }
           System.out.print(list1.indexOf(x));
        }
    }
}