在 java ArrayList 中搜索 [英] search in java ArrayList
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问题描述
我正在尝试找出在 ArrayList
中按客户 ID 号搜索客户的最佳方法.下面的代码不起作用;编译器告诉我我缺少 return
语句.
I'm trying to figure out the best way to search a customer in an ArrayList
by its Id number. The code below is not working; the compiler tells me that I am missing a return
statement.
Customer findCustomerByid(int id){
boolean exist=false;
if(this.customers.isEmpty()) {
return null;
}
for(int i=0;i<this.customers.size();i++) {
if(this.customers.get(i).getId() == id) {
exist=true;
break;
}
if(exist) {
return this.customers.get(id);
} else {
return this.customers.get(id);
}
}
}
//the customer class is something like that
public class Customer {
//attributes
int id;
int tel;
String fname;
String lname;
String resgistrationDate;
}
推荐答案
编译器正在抱怨,因为您当前在 for 循环中有 'if(exist)' 块.它需要在它之外.
The compiler is complaining because you currently have the 'if(exist)' block inside of your for loop. It needs to be outside of it.
for(int i=0;i<this.customers.size();i++){
if(this.customers.get(i).getId() == id){
exist=true;
break;
}
}
if(exist) {
return this.customers.get(id);
} else {
return this.customers.get(id);
}
话虽如此,有更好的方法来执行此搜索.就我个人而言,如果我使用的是 ArrayList,我的解决方案将类似于 Jon Skeet 发布的解决方案.
That being said, there are better ways to perform this search. Personally, if I were using an ArrayList, my solution would look like the one that Jon Skeet has posted.
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