java 意外类型所需变量找到值

Unexpected type required variable found value

提问by user1633277

public class example
{
    public ArrayList<Integer> ToFill = new ArrayList<>();

    public void Alter(int Value , int Position)
    { 
      ToFill.get(Position) = Value ;  // this line has an error 
    }
}

For some reason this code gives compilation Error ,could anyone explain why?

出于某种原因，这段代码给出了编译错误，谁能解释一下原因？

回答by Eng.Fouad

ToFill.get(Position)returns a value where the left-hand side of the assignment must be a variable. Instead, use set(index, element)as follows:

ToFill.get(Position)返回一个值，其中赋值的左侧必须是一个变量。相反，使用set(index, element)如下：

ToFill.set(Position, Value);

However, what you are doing is only valid if you are using arrays, for example:

但是，您所做的仅在使用数组时才有效，例如：

Integer[] array = ...
array[Position] = Value;

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As a side note, always use Java naming convention:

作为旁注，始终使用 Java 命名约定：

• toFillinstead of ToFill
• alterinstead of Alter
• positioninstead of Position.
• valueinstead of Value.

• toFill代替 ToFill
• alter代替 Alter
• position而不是Position.
• value而不是Value.