检查结构中是否存在密钥 [英] Checking for key existence in structure

问题描述

我有一个名为 #cfData＃的变量，其中包含结构数组。从图像中可以清楚地看到，第一个结构数组有6个键，而第二个结构只有两个键，即日期和打开。

I have a variable named #cfData# which contains an array of structures. As it's clear from the image, for 1st structure array there are 6 keys and for 2nd, only two keys,viz date and open.

如果我运行一个通用循环，则需要遍历每一个键，第二个数组元素将出现错误。因此，只有当所有键都存在于结构中时，以下命令才起作用：

If I run a common loop, to go through each and every key, I will get an error at second array element. So the following only works when all the keys are present in the structure:

<cfset blockedtotal = 0 />
<cfset bouncetotal = 0 />
<cfset blocked = 0/>
<cfset datetotal = 0 />

<cfloop array = #cfData# index = "i">
<cfset blockedtotal += i.blocked />
<cfset bouncetotal += i.bounce />
</cfloop>

在线阅读后，我有了使用StructKeyExists的想法，我认为我可以按照以下方式进行：

After reading online, I got an idea of using StructKeyExists where I think I can proceed in the following way:

<cfif structKeyExists(cfData,"bounce")>
<cfoutput>Bounce:#cfData.bounce#"/></cfoutput>
<cfelse>
<cfoutput> Bounce : [none]<br/></cfoutput>
</cfif>

但是我想知道在哪里我到底应该在cfloop中插入上面的代码吗？请告知我的方法是否错误。

But I am wondering, where exactly should I insert the above code inside the cfloop? Please advise if my approach is wrong.

更新：

谢谢大家，我根据答案使用以下代码来运行它，并且运行良好：

Thanks guys. I got it running by using the following code based on the answers and it's running fine:

<cfloop array="#cfData#" index="i">
  <cfif structKeyExists(i, "date")>
    <cfset counter++>
   <cfoutput>#counter#</cfoutput> Date  is: <cfoutput> #i.date#</cfoutput> <br/>
  </cfif>
</cfloop>

推荐答案

您不需要您可以使用

<cfloop array="#cfData#" index="i">
  <cfloop collection="#i#" item="key">
    struct with key '#key#'  has data: #i[key]#
  </cfloop>
</cfloop>

Of，如果您需要确定结构是否具有某些键，请执行以下操作：

Of, if you need to decide if the struct has certain key, do something:

<cfloop array="#cfData#" index="i">
  <cfif structKeyExists(i, "someKey")>
    <cfset counter++>
  </cfif>
</cfloop>

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