在ruby中定义一个等于nil的索引并返回false [英] Define an index in ruby equal to nil and return false

问题描述

我正在尝试定义一种方法，该方法检查电路板上的给定空间是否为空，并解决了符合文字不等于空格的场景。



我的测试未能产生false / true，而是提供了nil。



什么我试过了：



board = [，，，，，，， ，]

def position_taken？（董事会，指数）

如果董事会[index] == [] ||没有

假装

elsif board [index]！= []

put true

end < br $> b $ b结束

结束

I am trying to define a method that checks if a given space on the board is empty and address the scenarios that qualify as an empty space that isn't equal to the literal " ".

My tests failed to produce false/true, and instead provided nil.

What I have tried:

board = [" ", " ", " ", " ", " ", " ", " ", " ", " "]
def position_taken?(board, index)
if board[index] == [" "] || nil
puts false
elsif board[index] != [" "]
puts true
end
end
end

推荐答案

引用：

我的测试未能产生false / true，而是提供了nil。

My tests failed to produce false/true, and instead provided nil.

原因是你的代码没有涵盖所有情况。

尝试这样的事情：

The reason is that your code do not cover all cases.
Try something like this:

board = [" ", " ", " ", " ", " ", " ", " ", " ", " "]
def position_taken?(board, index)
    if board[index] == [" "] || nil # not sure what this is supposed to be
        puts false
    elsif board[index] != [" "]
        puts true
    else
        # put a warning message here and you will have surprise
    end
end
end

原因是 board [index] == [] || nil 和 board [index]！= [] 不是补充条件。

如果第二个条件应该作为第一个补充，代码应该简单：

The reason is that board[index] == [" "] || nil and board[index] != [" "] are not complementary conditions.
In case second condition should be complement of first, the code should be simply:

board = [" ", " ", " ", " ", " ", " ", " ", " ", " "]
def position_taken?(board, index)
    if board[index] == [" "] || nil
        puts false
    elsif board[index] != [" "]
    else
        puts true
    end
end
end

Nota：我有从未使用Ruby，我只知道其他语言的常用用法。

Nota: I have never used Ruby, I just know common usages in other languages.

def position_taken？（board，index）

if board [index] ==| | board [index] == nil || board [index] ==

返回false

elsif board [index]！=

返回true

结束

结束



感谢您的帮助，我最终发现这个解决方案有效，看看问题是怎么回事你解释了我的代码。

def position_taken?(board, index)
if board[index] == " " || board[index] == nil || board[index] == ""
return false
elsif board[index] != " "
return true
end
end

Thank you for your help, I ended up finding this solution worked and what the problem was by seeing how you interpreted my code.

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