Question

我有一个Postgres数据库。我的一个表中的一列包含数组。它被称为public override Move GetMove(Board board) { List<Move> moves = board.getMoveList(); double bestValue, currentValue; ; Move bestMove = moves.First(); Board firstBoard = board.DeepClone(); firstBoard.Move(bestMove); bestValue = Evaluator(firstBoard); List<Move> tieMoves = new List<Move>(); foreach (Move aMove in moves) { Board board2 = board.DeepClone(); board2.Move(aMove); // If there is a move in one take it and leave if (board2.WhoWon() == side) return aMove; // check player 2 moves foreach (Move bMove in moves) { Board board3 = board2.DeepClone(); board3.Move(bMove); // If there is a move in one take it and leave if (board3.WhoWon() == side) return aMove; // check player 1 future moves foreach (Move bMove in moves) { Board board4 = board3.DeepClone(); board4.Move(cMove); // If there is a move in one take it and leave if (board4.WhoWon() == side) return aMove; currentValue = Evaluator(board4); if ( (side == Pieces.ATTACK && currentValue > bestValue) || (side == Pieces.DEFEND && currentValue < bestValue) ) { tieMoves = new List<Move>(); tieMoves.Add(aMove); bestMove = aMove; bestValue = currentValue; } } } } // Pick one from the candidate moves with the same value return tieMoves.ElementAt(random.Next(tieMoves.Count)); }。我正在尝试合并两个实例，但是当我尝试合并数组时，它们没有保存。

import static java.lang.System.*;
import static javax.swing.JOptionPane.*;
import static java.lang.Integer.*;

public class SimpleCalc {

    public static void main(String[] args) {

        String operator = showInputDialog("Choose operation: " + "\n" +
                "[1] = Plus" + "\n" +
                "[2] = Minus" + "\n" +
                "[3] = Multiply" + "\n" +
                "[4] = Divide" + "\n");

        int c = parseInt(operator);

        if (c > 4) {
            showMessageDialog(null, "You cant do that.");

        } else if (c == 1) {
            String textA = showInputDialog("Enter first number: ");
            String textB = showInputDialog("Enter second number: ");
            int a = parseInt(textA);
            int b = parseInt(textB);
            showMessageDialog(null, a + " + " + b + " = " + (a + b));

        } else if (c == 2) {
            String textA = showInputDialog("Enter first number: ");
            String textB = showInputDialog("Enter second number: ");
            int a = parseInt(textA);
            int b = parseInt(textB);
            showMessageDialog(null, a + " - " + b + " = " + (a - b));

        } else if (c == 3) {
            String textA = showInputDialog("Enter first number: ");
            String textB = showInputDialog("Enter second number: ");
            int a = parseInt(textA);
            int b = parseInt(textB);
            showMessageDialog(null, a + " * " + b + " = " + (a * b));

        } else if (c == 4) {
            String textA = showInputDialog("Enter first number: ");
            String textB = showInputDialog("Enter second number: ");
            int a = parseInt(textA);
            int b = parseInt(textB);
            showMessageDialog(null, a + " / " + b + " = " + (a / b));
        }
    }
}

但是当我检查aliases时，别名没有合并。

irb(main):001:0> original
=> #<Thing id: 1, name: "Foo", aliases: ["Foo"]>
irb(main):002:0> duplicate
=> #<Thing id: 2, name: "Bar", aliases: ["Bar"]>
irb(main):003:0> original.aliases | duplicate.aliases
=> ["Foo", "Bar"]
irb(main):004:0> original.save!                      
(0.3ms)  BEGIN
Thing Exists (0.8ms)  SELECT  1 AS one FROM "thing" WHERE "things"."name" = $1 AND ("thing"."id" != $2) LIMIT $3  [["name", "Foo"], ["id", 1], ["LIMIT", 1]]
(0.3ms)  COMMIT
Thing Store (6.1ms)  {"id":1}
=> true

我尝试了几种不同的方式将original插入irb(main):005:0> original => #<Thing id: 1, name: "Foo", aliases: ["Foo"]>，但似乎没有任何保存。有什么想法吗？我错过了什么吗？

编辑：我在Rails 5.1.4和Ruby 2.5.0p0

上

Answer 1

你是否在Rails 3上？我注意到Rails3 activerecord数组处理不喜欢内联更新。您需要使用临时变量，扩充该变量，然后将其分配回来。

aliases = original.aliases # make a temp variable
aliases = aliases | duplicate.aliases # modify temp variable
original.aliases = aliases # assign back
original.save! # now you can save

当我试图推进阵列时，我自己遇到了这个问题：

original.aliases << "something" # aliases would never get changed

更新到ActiveRecord列中的数组而不保存

1 个答案: