How to access a JSON structure key that starts with a number

[msoultan]

I've got an odd issue here.  I'm accessing someone else's JSON structure so I am not able to change it.  The JSON structure keys are named with both characters and numbers like this:

0	198456
product_id	198456
1	Rashaan Houston feat Tony Loreto
artist	Rashaan Houston feat Tony Loreto

So, in other words, there's a key named "0" and a key named "product_id", both of which contain the same key.  Why they did that, I don't know, but they did.

In one of the instances, the data stored under the text-named key isn't the same as the numerical-named key.  I tried to output the data in the numerical key like this (it's an array of structures):

#strStompyJSON.data[1].0#

but I get the following error:

--

Invalid CFML construct found on line 41 at column 31.

ColdFusion was looking at the following text:

.0

--

When I do the following, it works fine:

#strStompyJSON.data[1].product_id#

So it looks as though CF doesn't like accessing a variable that starts with a number.  I am able to loop through the structure using a collection loop, and it outputs all of the keys (including the numerical ones) and their values using the following code:

<cfloop collection="#strStompyJSON.data[1]#" item="key">
#key#: #strStompyJSON.data[1][key]#<br />
</cfloop>

However, that doesn't allow me a way to access specific keys named with a number.  Is there a way that I can specifically access a key that is named with a number?

thanks!

Mike

[msoultan]

I made an information page which might be helpful so you can see all the data:

http://cfdev.cota.csulb.edu:8080/stompy/json.cfm

all of the data is live data.  Let me know if you have any questions

[existdissolve]

Just out of curiosity, why exactly do you need to reference the numbered keys?  From the looks (a quick look, mind you) of the data that is returned, there appears to be a pretty solid correlation between the numbered keys and the labeled keys.

For example, data[0] *appears* to line up with data['image'], data[1] *appears* to line up with data['artist'], and so on.  If these are consistently the same across the data set returned, why try to reference the numeric keys as opposed to the labeled keys?

[Sorry, after posting this I noticed that you laid these out in the link you provided.]

Message was edited by: existdissolve

[msoultan]

Well, it was date that I needed to use, but sometimes the two versions don't match up for some reason or another.

Any ideas how to access the numerical values?

thanks!

Mike

[existdissolve · Accepted solution]

Did you try the bracket notation that I suggested in my first response?  In my tests with your code, it worked without issue.

Thanks

[msoultan]

Oh jeez - I missed that first email of yours.  I tried the bracket notation and that worked perfectly!

http://cfdev.cota.csulb.edu:8080/stompy/json.cfm

Thanks!!

Mike

[existdissolve]

No problem--glad it worked out.

As a follow-up to this, I'd encourage you to keep the bracket notation in mind during future development.  It is EXTREMELY useful in a lot of situations.

For example, if you're building a structure on the fly with dynamic keys, bracket notation is extremely helpful:

     <cfset authors = structnew()>

     <cfloop list="authorlist" index="name">

          <cfset authors[name] = getbooklist(name)>

     </cfloop>

Also, bracket notation is really nice when creating json from ColdFusion structures.  Consider this:

     <cfset author = structnew()>

     <cfset author.name = "Neil Gaiman">

     <cfset author.genre = "Fantasy">

     <cfset author.awesome = true>

     <cfset authorjson = serializejson(author)>

By default, the serialized json produced will have all UPPER CASE keys.  Not a big deal in most cases, but if you're returning the json to something (like a JS library) that is expecting keys in a certain case, it can be a problem.  Fortunately, bracket notation allows you to specify exactly what case you want the structure's keys to be in:

     <cfset author = structnew()>

     <cfset author['name'] = "Neil Gaiman">

     <cfset author['Genre'] = "Fantasy">

     <cfset author['AWESOME'] = true>

     <cfset authorjson = serializejson(author)>

[msoultan]

Yeah - I was wondering if there was another type of notation, but I couldn't find it anywhere.  Thanks again!!

[existdissolve]

With ColdFusion structures, you can access keys with dot or bracket notation.  As you've discovered, using dot notation doesn't work so well when the key is a number.

So just use bracket notation.

Instead of:

#strStompyJSON.data[1].0#

Try:

#strStompyJSON.data[1][0]#

This looks exactly like the collection loop you posted, and that's because this is really what the collection loop is doing anyway--the only difference is that in this example you've explicitly specified the value of the key instead of having CF iterate through all the keys.

Hope this helps!

Message was edited by: existdissolve