Java 如何返回数组的副本？
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How to return a copy of an array?
提问by Frightlin
public void addStudent(String student) {
String [] temp = new String[students.length * 2];
for(int i = 0; i < students.length; i++){
temp[i] = students[i];
}
students = temp;
students[numberOfStudents] = student;
numberOfStudents++;
}
public String[] getStudents() {
String[] copyStudents = new String[students.length];
return copyStudents;
}
I'm trying to get the method getStudents to return a copy of the array that I made in the addStudent method. I'm not sure how to go about this.
我试图让方法 getStudents 返回我在 addStudent 方法中创建的数组的副本。我不知道该怎么做。
采纳答案by Fedor Skrynnikov
public String[] getStudents() {
return Arrays.copyOf(students, students.length);;
}
public String[] getStudents() {
String[] copyStudents = new String[students.length];
System.arraycopy(students, 0, copyStudents, 0, students.length);
return copyStudents;
}
3 clone
3克隆
public String[] getStudents() {
return students.clone();
}
Also see the answerabout performance of each approach. They are pretty the same
另请参阅有关每种方法性能的答案。他们很相似
回答by Stewart
System.arraycopy(students, 0, copyStudents, 0, students.length);
回答by Fedor Skrynnikov
try this:
尝试这个：
System.arraycopy(students, 0, copyStudents, 0, students.length);
回答by Mureinik
Java's Systemclass provides a utility method to this:
Java 的System类为此提供了一个实用方法：
public String[] getStudents() {
String[] copyStudents = new String[students.length];
System.arraycopy(students, 0, copyStudents, 0, students.length );
return copyStudents;
}
回答by 1ac0
回答by Ankur Shanbhag
You can use Arrays.copyOf()to create a copy of your array.
您可以使用Arrays.copyOf()创建数组的副本。
OR
或者
You can also use System.arraycopy().
您还可以使用System.arraycopy()。
回答by Ruchira Gayan Ranaweera
You can use Arrays.copyOf().
您可以使用Arrays.copyOf()。
Eg:
例如：
int[] arr=new int[]{1,4,5};
Arrays.copyOf(arr,arr.length); // here first argument is current array
// second argument is size of new array.
