Question

为什么我的三元忽略了第一个条件($order->status === "prepairing")？

在检查订单状态时，它总是跳过第一个条件，并立即转到第二个条件（并且总是将其视为真）

$messageMiddle = (  ($order->status === "prepairing") ? " your prder is being prepared. Make your way towards the store." 
                  : ($order->status === "complete")   ?' your order is done! Please show your order-code at the store.' 
                  : ' thank you for ordering ');

Answer 1

您需要按如下所示将括号中的每个下一个表达式分组。您忘了将第二元表达式用括号括起来。

Vx0 = 18
Vy0 = 18
V = 18
Theta = 45
y0 = 1.8    
x0 = 0
p = 1.2#given density
C = 0.3#Drag coefficient
dt = 0.2#Time increment

def x_direction (x0, Vx0, dt):
"""Calculate the distance moved in x axis"""
new_dist = 0
for hori_dist in range(5):
   hori_dist = x0 + Vx0*dt
   new_dist = new_dist + hori_dist
return new_dist

new_dist = x_direction(x0, Vx0, dt)
print ("Distanced moved in x direction is :", new_dist)

但是您还是应该避免这种方法。

Answer 2

对订单状态做出反应的更好方法是使用switch statement。像这样：

 <!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
<title></title>
</head>
 <body>
     <form id="form1" runat="server">
  var text = Request.Params[0];

             XDocument xdoc = XDocument.Load(Server.MapPath("~/cours.xml"));
             XDocument xresp = new XDocument(new XElement("tousCours"));

             if (text != "")
             {
                 IEnumerable<XElement> prog =
                     from b in xdoc.Elements("tousCours").Elements("cours")
                     where (string)b.Element("prgs/pr") == text 
                     select b;
                 foreach (XElement xEle in prog)
                     xresp.Element("tousCours").Add(xEle);
             }
             Response.Clear();
             Response.ContentType = "text/xml";
             Response.ContentEncoding = System.Text.Encoding.UTF8;
             xresp.Save(Response.Output);
             Response.End();

很容易看出如何扩展它以对其他状态字做出反应。

请注意，我将“ prepairing”更改为“ preparing”。

程序员追求的目标之一就是简洁的代码。但是，较短的代码并不总是更好的代码。它的可读性较低，维护和扩展起来也更加困难。

三元忽略第一个条件

2 个答案: