I have a shopping cart array stored in a session:
I give my user the ability to select all items to delete or select individual items via a checkbox.
I am sending the array index via form post to arrayDeleteAt.
Now if I select the bottom 3 items, it does not delete it.
Here is my delete code:
<cfif isDefined("form.leadId") AND listLen(form.leadId)>
<cfloop from="#listLen(form.leadId)#" to="1" step="-1" index="i">
<cfset temp = arrayDeleteAt(session.shoppingcart, #i#)>
</cfloop>
</cfif>
You are going to have more issues with this method of managing your cart. After using ArrayDeleteAt the array's indexes will be recalculated, so when you will most likely delete the wrong item from the array, or you can get an error when you try and delete an item that is out of bounds.
Is see that you are trying to get around this by working backwards through your list, and Dan is right for what your issue is with the code above, but if the list is passed in in an incorrect order then you are in a world of hurt.
I would suggest instead of using an array, use a struct with a surrogate key, such as a UUID, then delete items by that key.
The problem is that you're deleting at the position of the counter, and not the form field that's being passed in. Try this instead:
<cfset temp = arrayDeleteAt(session.shoppingcart, ListGetAt(FORM.leadID, i) />
UPDATE: To get around the issue Tyler mentioned, you can convert your list of indexes from FORM.leadID to an Array using ListToArray and then ArraySort to get them in the order necessary to make sure your deletes are correct.
While my answer does fix your immediate problem, you would definitely be better off following Tyler's advice and using a key for each item in the cart to make sure you're managing the one you actually think you're supposed to be managing :)
In CF 10 or Railo 4, this can be done using the most recent version of the Underscore.cfc library:
<cfscript>
if (structKeyExists(form, 'leadId') && listlen(form.leadId)) {
_ = new Underscore();
variables.shoppingCart = duplicate(session.shoppingCart);
variables.newCart = _.reject(variables.shoppingCart, function(val, index){
return _.include(form.leadId, index);
});
}
</cfscript>
<cfif structKeyExists(variables, "newCart") >
<cflock scope="session" type="exclusive" timeout="10">
<cfset session.shoppingCart = variables.newCart>
</cflock>
</cfif>
You'll see that I'm copying the shopping cart into the variables scope, editing it, then copying it back (with a lock) if necessary. I would've done this all in cfscript if it were possible to write cflocks in cfscript.
(Disclaimer: I wrote Underscore.cfc)
Related
Let's say I have struct :
struct Planet {
var id : UUID
var name: String
...
}
I have an array of such structs which is constructed from data fetched from a database. I use this for a form in a browser where the user can:
edit the fields (eg change the name of Planet)
create one or more new Planets
at this time the user may not delete a Planet but it would be great if the solution would support that too
When the form is submitted I get an array with those structures (the order is also not the same as the original). What is the best/most efficient way to do update the data in the original array with the data from the second.
My current idea is:
map the original array to a dictionary with key= id, value= aPlanetStructure
loop over the second array (with the edited data) and if that 'key' can be retrieved in the dictionary (=data from first array)-> update the struct there, if not create an additional planet in the first array.
I'm not sure if this is a good approach, it seems like there could be a more efficient way (but I can't think of it). It would also not support deleting a Planet
In general, if you can separate out the elements of the array by action, you'll make your life easier.
For example:
var created= [Planet]()
var updated= [Planet]()
var deleted = [Planet]()
In your UI layer, when an edit is made, add the edited planet to the
updated array, when a planet is deleted, add it to the deleted array, etc.
Submit all 3 arrays with your form.
Loop over the results of each and pass too your create, update, and delete methods that access your database.
That will require restructuring your form code a bit, but... in general it's easier in your UI layer to tell whether someone is doing a create, an update, or a delete, than it is to mush them all together and try to figure it out after the fact by doing comparisons.
I'm new to Firebase and have a function that writes all of my event ID's to an array. I want to use the last value in that array (the last event ID) to lookup the children of that specific eventID.
I know how to get the last item in the array but how do I put that into my .child() path?
I tried the code below, but it doesn't seem to work. I'm guessing that because .child("(lastEvent)") isn't a valid path.
let lastEvent = eventIDArray.last
refHandle = ref.child("Bouts").child("\(lastEvent)")
How do I plug the lastEvent value in as my path? Or is that even possible? Again, total newbie- alternatives welcome.
Sorting and filtering data
you can use sorting and filtering function to get the item.
To get the last item you can write the query like this.**
let recentBoutsQuery = (ref?.child("Bouts").queryLimited(toLast: 1))!
This will return 1 entry from last of your database which the last entry.
You can learn more from the firebase documentation. Work with Lists of Data
How do I remove an item from an array at a specific index without permanently removing the item from the array? I have
my_data_col.tap{|i| i.delete_at(index)}.select{|item| ... }
I notice that, after the call, my_data contains one element fewer than it did when I started. How do I remove the element at the index without permanently altering the array?
Given your example in #Ursus's post (now deleted) I would execute as follows:
my_data_col.select.with_index do |str,idx|
str.respond_to?(:downcase) && idx != index
end.map(&:downcase).uniq
Next time please post your full example so people can assist more easily
This is a follow up question to: Append to JSON array with ColdFusion, taking Null values into consideration?
That question was answered yesterday and worked perfectly (Thank you Kevin B. and Leigh!). However, the application I am pulling my JSON data from threw me a curve ball this morning. Sometimes, depending on the data I am requesting, it returns the entire JSON as an array like this:
[
{
"loginHosts": [
"server1.example.com"
],
"sudoHosts": [
"server1.example.com"
],
"CPG": [
"my_group"
],
"mail": "myuser#example.com",
"loginShell": "/bin/bash"
}
]
I don't know why that application does this. If I knew this was a possibility I would have added that information to my previous question, my apologies.
My attempts to find a solution lead me here first: Using JSON Data with Coldfusion . Looping over the JSON array as a collection seemed to work, but only if none of the array values were Null. I thought using this code, as in the previous question, would work if I used it for all the JSON fields:
<cfif NOT structKeyExists(myStruct, 'sudoHosts') OR NOT isArray(myStruct.sudoHosts)>
<cfset myStruct.sudoHosts = []>
</cfif>
This was not the case. I continually get:
Error: Can't cast Complex Object Type Array to String
Looking through the debug output, Lucee did throw this out: string Use Built-In-Function "serialize(Array):String" to create a String from Array. I did more digging and found this article: Railo tip: store complex data by using serialize(data). Sadly, Null values have struck again. Also, my understanding is serialize() is similar to evaluate(), and not recommended.
I will continue looking for a solution but any help is, as always, greatly appreciated!
-- EDIT --
I came across this thread: ColdFusion JSON object vs array of objects. I noticed the JSON in the question is an ARRAY [], and I applied the answer to my code, but am still running into the Null problem. I guess I don't know how to check for nested Null values. :(
Take it one step at a time.
Ideally you should determine why the response differs. Since you say those differences usually correspond to something different in your request, that strongly suggests you may be overlooking (or possibly misunderstanding) something in the remote API. I would recommend re-reviewing the API to identify that "something", in order to figure out the right approach. Otherwise, the code will quickly become unmanageable and inefficient as you continue to tweak it to handle each "new" situation.
If for some reason the API truly is returning different results without a valid reason, the best you can do is to code according to what you expect and fail gracefully when you receive something else. Start by listing the expected possibilities:
Response is a single structure containing certain keys OR
Response is an Array of structures containing certain keys
Based on the above, you can use the IsArray and IsStruct functions to determine the format of the response, and handle it accordingly. First examine the deserialized object. If it is an array, extract the structure in the first element (Note, I am assuming the array only contains a single element, as in the example. If it can contain multiple elements, you will need additional handling).
<cfset data = deserializeJson(originalJSON)>
....
<!--- Extract structure from first element of array --->
<cfif IsArray(data) && arrayLen(data)>
<cfset data = data[1]>
</cfif>
Next verify you are now working with a structure, containing the expected key(s). If so, go ahead with your usual processing. Otherwise, something unexpected happened and the code should perform the appropriate error handling.
<!--- Verify object is a structure and contains expected key(s) --->
<cfif IsStruct(data) && structKeyExists(data, "loginHosts")>
... process data as usual
<cfelse>
... data is not in expected format, do error handling here
</cfif>
The above is a very quick and dirty example, but should demonstrate the basic idea. As long as you are certain you are using the API correctly, all you can do is code for the expected and fail gracefully when something different happens.
Here is Google calendar data retrieved from https://www.googleapis.com/calendar/v3/users/me/calendarList.
The response is in JSON, so I used the ColdFusion method deserializeJson to turn it into a CFML structure.
I cannot figure out the syntax to loop over this data. You'll see that within the CFML struct, 'items' is an array of calendars returned from Google, and every attempt to access the array within the struct generates a Java string conversion error or a syntax error, likely because I can't get the syntax correct.
Any help is very appreciated, thanks very much
Some trial and error will help - you are already on your way. The root object you dumped out already but we'll do it here to represent the object you dumped out as "obj":
<cfset obj = deserializejson(googleCal)>
The first level is a struct so you would address them as follows:
#obj.etag# // this is a string
items contains an array. So you have items[1-n] ... however many are in the array. This code would set myArrayObj as an array with 3 items (based on the dump above).
<cfset myArrayObj = obj.items>
You can verify using isArray:
#isArray(myArrayObj)#
Each array member contains a struct in turn so you can output:
#myArrayObj[1].accessRole# // this would be a string
... And so on. Make a note that index item 3 in the array is a blank struct so you need to "check" to see if the struct is empty before you work with it's keys. Investigate "structKeyExists()" for that purpose.
If you want to deal with each of the "items" in a loop (a pretty typical choice) you would simply do a cfscript loop or cfloop using array as in:
<cfloop array="#myArrayObj#" index="i">
<cfif structKeyExists(myArrayOb[i], "accessRole")>
#myArrayObj[i].accessRole#
</cfif>
</cfloop>
Hope this helps. Good luck!