Question

当我运行以下代码时：

cnum = randNum = 0
solutions = []
result = Hash.new

print "What's the number of people playing? "
n = gets.chomp.to_i

while cnum < n
    cnum += 1
    loop do
        randNum = rand(1 .. n)
        break unless (solutions.include? randNum) || randNum == cnum
        if solutions.include? n = false # If n isn't in the solution
            r = rand(1 ... n)
            randNum = r
            result[result.key(r)] = n
        end
    end
    solutions.push randNum
    result[cnum] = randNum
end

result.each do |player, result|
    print "Player #{player}, your player is Player #{result}"
    gets.chomp
end

我收到以下错误：

gbourdon@Thor-Mint ~/workspace/secretSanta $ ruby code.rb
What's the number of people playing? 5
code.rb:11:in `block in <main>': bad value for range (ArgumentError)
        from code.rb:10:in `loop'
        from code.rb:10:in `<main>'

但是，当我删除这部分代码时：

if solutions.include? n = false # If n isn't in the solution
            r = rand(1 ... n)
            randNum = r
            result[result.key(r)] = n
        end

该程序有效（尽管有一些错误，上面的代码片段的目标是修复）。为什么会这样，我该怎么做才能解决它？另外，为什么只有在添加了代码块时才会出现错误？

Answer 1

Ruby将此行视为

if solutions.include?(n = false) # If n isn't in the solution

因此，您要将n分配给false并检查solutions是否在n。如果没有，则再次循环，这次false仍然等于randNum = rand(1 .. n)，然后尝试创建一个新范围：

n == false

并且该错误消失了，因为自1以来，您正在尝试创建从false到if solutions.include?(n) == false # If n isn't in the solution的范围，最终导致错误。

你可能想检查

if !solutions.include? n # If n isn't in the solution

或者，更简洁

unless solutions.include? n # If n isn't in the solution

或

<?php
require '../models/connection.php';
session_start();

$user_id = $_SESSION[‘user_id'];

$query=mysql_query( "select post_id from User where user_id=$user_id");
if (mysql_num_rows($query) > 0)
{
  $row = mysql_fetch_assoc($query);

  $query = mysql_query("

select text_posts.*,video_posts.*,image_posts.*
from (( text_posts outer
join video_posts on text_posts.post_id= video_posts.post_id)outer
join image_posts on image_posts.post_id= text_posts.post_id)");


 $data = array();
 echo mysql_num_rows($query);
  if (mysql_num_rows($query) > 0)
  {
    while ($row = mysql_fetch_assoc($query)) 
    {
      array_push($data,$row);
    }
    $response = array(
      "code" => 200,
      "message" => "Success",
      "records" => $data
    );
 } 
 else
 {
    $response = '{"code":204,"message":"No posts"}';
 }
} else 
{
  $response = '{"code":204,"message":"Incorrect userid"}';
}
echo stripslashes(json_encode($response));
 ?>

代码块

1 个答案: