[英]how to subtract ArrayList using removeall() in java?
我在Java中有數組列表:
List<Correction> Auv=new ArrayList<>();
List<Correction> Produv=new ArrayList<>();
然后我想用Auv減去Produv的值,這是一個例子:
Produv.add(new Correction("a","b"));
Produv.add(new Correction("a","c"));
Produv.add(new Correction("b","d"));
Produv.add(new Correction("b","c"));
Auv.add(new Correction("c","a"));
Auv.add(new Correction("b","c"));
Produv.removeall(Auv);
但是沒有減去任何東西,數組仍然包含它的初始值,有什么辦法嗎? 我嘗試覆蓋equals(),仍然得到相同的結果
這里是我的改正類的代碼:
public class Correction {
private String node0;
private String node1;
public Correction(String node0, String node1) {
this.node0 = node0;
this.node1 = node1;
}
public void setNode0(String node0){
this.node0=node0;
}
public void setNode1(String node1){
this.node1=node1;
}
public String getNode0(){
return node0;
}
public String getNode1(){
return node1;
}
@Override
public boolean equals(Object object){
boolean same = false;
if (object != null && object instanceof Correction)
{
same = this.node0 == ((Correction) object).node1 && this.node1 == ((Correction) object).node1;
}
return same;
}
}
解決了!! 這只是在重寫equals()方法(感謝伙計們)時出現的錯誤,這里是我的修正:
@Override
public boolean equals(Object object){
boolean same = false;
if (object != null && object instanceof Correction)
{
same = (this.node0 == ((Correction) object).node1 && this.node1 == ((Correction) object).node0)||(this.node0 == ((Correction) object).node0 && this.node1 == ((Correction) object).node1);
}
return same;
}
您的equals方法看起來不對。 比較this.node0
與((Correction) object).node0
更有意義。
我認為應該是:
public boolean equals(Object object){
boolean same = false;
if (object != null && object instanceof Correction)
{
same = this.node0.equals(((Correction) object).node0) && this.node1.equals(((Correction) object).node1);
}
return same;
}
另外,這是錯字嗎?
Auv.add("c","a");
Auv.add("b","c");
可能應該是:
Auv.add(new Correction ("c","a"));
Auv.add(new Correction ("b","c"));
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