I'm trying to use the ABPerson method searchElementForProperty:... to create a moderately complex search. In particular, I want to find the set of people who have an email address that ends with "foo.com", and are NOT part of the pre-populated group "My workunit".
Matching against just the email address seems to be trivial. Creating a conjunction against the (inverse of the) group membership seems impossible.
Yes, I can do this by doing the obvious explicit cross-checking myself, but if the point of having search functionality directly in Address Book is to optimize performance, wouldn't it make sense for the search facility to be sufficiently complete to be able to do this?
Thanks in advance,
Tony
You could potentially copy all the data from the address book into a Core Data store and use predicates to work with that data. Predicates tend to be very useful when building complex queries.
Predicate Programming Guide
In this case you would have to get all contacts ([[AddressBook sharedAddressBook] people]) and also have a Core Data entity called Contact (or something similar) that would save names, emails, addresses and other properties from the ABPerson object.
Having this you can probably create an NSPredicate to filter with the conditions you want.
Groups reference their members according to recordId. The only way I have found to perform such an operation is here: how to find parent groups of a person. It is not a simple thing like we would like. It seems that Apple is not concerned about group searching which would be extremely useful.
Related
Is it possible, using the AWS Ruby SDK (or just DynamoDB in general), to get an item or items from a table that uses a primary key only, and where that primary key ends with a certain string?
I haven't come across anything in the docs that explicitly answers this question, either in the ruby ddb docs or the general docs for ddb. I'm not saying the question is not answered, but if it is, I can't find it.
If it is possible, could someone provide an example for ruby or link to the docs where an example exists?
Although #Ryan is correct and this can be done with query, just bear in mind that you're doing a "full-table-scan" here. That might be OK for a one-time job but probably not the best practice for a routine task (and of course not as a part of your API calls).
If your use-case involves quickly finding objects based on their suffix in a specific field, consider extracting this suffix (assuming it's a fixed-size suffix) as another field and have a secondary index on that one. If you want to query arbitrary length suffixes, I would create a lookup table and update it with possible suffixes (or some of them, to save some calls, and then filter when querying).
It looks like you would want to use the Query method on the SDK to find the items your looking for. It seems that "EndsWith" is not available as a comparison operator in the SDK though. So you would need to use CONTAINS and then check your results locally.
This should lead to the best performance, letting DynamoDb do the initial heavy lifting and then further pruning the results once you receive them.
http://docs.aws.amazon.com/sdkforruby/api/Aws/DynamoDB/Client.html#query-instance_method
Is there a data structure within LiveCode that can be used as a "holder" for associated data, letting me handle it collectively? I come from a Java / Javascript / C background so I am looking for a Class or Struct sort of data structure.
I've found examples of Groups, which seem to have some of this functionality, but it feels a bit like I'm bending the language to meet my needs.
As a specific example, suppose I had an image field on my screen that would randomly display an image and, when pressed, play an associated sound clip. I'd expect to create a list of "structures" that contained the path to the image and the path to the associated sound clip, and use that data to populate the image field and to decide what sound clip to play.
Would a Group be the correct structure to use in this case? Or am I approaching this in a way that isn't really fitting with the way LiveCode works?
It takes a little getting used to, but the xTalk world is much simpler and more open than any ordinary procedural language. So much of what you once had to manage is no longer required.
So when splash21 said that you could store all your image and sound references in a custom property, he was really saying that the LiveCode environment contains intrinsic, high level functionality that makes these sorts of things instantly accessible, and the only thing required of you is to call for them, and they simply work.
The only way to appreciate this is to make a few simple programs, to really see what is possible. Make your application. Everything you mentioned can be accomplished with perhaps a dozen lines of code in a single handler. I recommend that you join the LiveCode use list and forums. The community is vibrant and eager to help, frequently with full blown solutions to specific problems, but more importantly, as guides and mentors to new users
Craig Newman
Arrays in LiveCode are actually associative arrays (like hash maps). A key is associated with a value. The value might be as well an array.
Chapter 5.5.7 of the User's Guide says
Array elements may contain nested or sub-elements, making them multi-dimensional.
This type of array is ideal for processing hierarchical data structures such as trees or
XML. To access a sub-element, simply declare it using an additional set of square
brackets.
put "ABC" into myVariable["myKeyName"][“aChildElement”]
see also
How to store pictures in a stack?
Dave- I'm hoping to get a struct-like container implemented in the near future. Meanwhile you can, as splash21 mentioned, use custom properties (or better yet, custom property sets) to do what you want. This will give you a pseudo-struct for each object and you can implement the file and sound specifications into the properties. And if you use that in conjunction with a behavior object you'll end up very close to a real inheritable class formation.
I am new at the idea of programming algorithms. I can work with simplistic ideas, but my current project requires that I create something a bit more complicated.
I'm trying to create a categorization system based on keywords and subsets of 'general' categories that filter down into more detailed categories that requires as little work as possible from the user.
I.E.
Sports >> Baseball >> Pitching >> Nolan Ryan
So, if a user decides they want to talk about "Baseball" and they filter the search, I would like to also include 'Sports"
User enters: "baseball"
User is then taken to Sports >> Baseball
Now I understand that this would be impossible without a living - breathing dynamic program that connects those two categories in some way. It would also require 'some' user input initially, and many more inputs throughout the lifetime of the software in order to maintain it and keep it up to date.
But Alas, asking for such an algorithm would be frivolous without detailing very concrete specifics about what I'm trying to do. And i'm not trying to ask for a hand out.
Instead, I am curious if people are aware of similar systems that have already been implemented and if there is documentation out there describing how it has been done. Or even some real life examples of your own projects.
In short, I have a 'plan' but it requires more user input than I really want. I feel getting more info on the subject would be the best course of action before jumping head first into developing this program.
Thanks
IMHO It isn't as hard as you think. What you want is called Tagging and you can do it Automatically just by setting the correlation between tags (i.e. a Tag can have its meaningful information plus its reation with other ones. Then, if user select a Tag well, you related that with others via looking your ADT collection (can be as simple as an array).
Tag:
Sport
Related Tags
Football
Soccer
...
I'm hoping this helps!
It sounds like what you want to do is create a tree/menu structure, and then be able to rapidly retrieve the "breadcrumb" for any given key in the tree.
Here's what I would think:
Create the tree with all the branches. It's okay if you want branches to share keys - as long as you can give the user a "choice" of "Multiple found, please choose which one... ?"
For every key in the tree, generate the breadcrumb. This is time-consuming, and if the tree is very large and updating regularly then it may be something better done offline, in the cloud, or via hadoop, etc.
Store the key and the breadcrumb in a key/value store such as redis, or in memory/cached as desired. You'll want every value to have an array if you want to share keys across categories/branches.
When the user selects a key - the key is looked up in the store, and if the resulting value contains only one match, then you simply construct the breadcrumb to take the user where you want them to go. If it has multiple, you give them a choice.
I would even say, if you need something more organic, say a user can create "new topic" dynamically from anywhere else, then you might want to not use a tree at all after the initial import - instead just update your key/value store in real-time.
I'm refactoring one of my projects - a shopping cart. One of the tightly coupled areas of my code is the "Viewer" class - to generate information for the user to see, it often needs a combination of two or more of the following objects:
The store catalog.
The customer's order.
The customer's mailing information.
I can't really break up the display methods, for various reasons.
Martin Fowler's Refactoring identifies this as a "Long parameter list" smell. The relevant refactoring here is "Introduce parameter object." I am, however, hesitant to do that, as doing so would couple loosely related data. It would also lock me to a very narrow one-to-one relationship between those three objects - while that would work for my application as it is now, it makes no real-world sense. (As there is only one store catalog, there can be many "Customer mailing information" objects, and each of those may be related to many "Customer's order" objects).
Does anyone have any elegant solutions to this?
A parameter list of three parameters needs no refactoring. Start worrying when you reach, say, 8 or 10 parameters.
Try to name the thing that binds a catalog, an order, and an address. Start, maybe with CatalogOrderAddressTuple. Ugly, isn't it? Well, maybe as a utility class of your Viewer, it should just be an inner class, where you could get by with just Tuple - or Data. Still ugly.
It doesn't sound like these belong as actual fields to the Viewer - but explore what that would look like, how your code would change if each Viewer were simply constructed with the data on which it operates.
As ammoQ & Ryan Prior have said, this isn't much of a smell, but I'd say it's worth playing with some alternatives before giving up entirely.
As stated by ammoQ, looking for refactoring opportunities with so few parameters is stretching.
See also: KISS and YAGNI.
It seems to me that introducing a parameter object would have the opposite effect of locking you to a one-to-one relationship between those three objects.
If a single customer address is being passed around, and in the future someone decides to separate billing address and shipping address, then it would probably be simpler to add the new address to a parameter object, rather than add a new parameter up and down the call stack.
(This is just an example, of course. Ideally, the address information would exist separately in the order and customer objects, since all information on posted orders should be immutable, even if the customer's address changes. But that wasn't what you were asking about!)
This is silly, but I haven't found this information. If you have names of concepts and suitable references, just let me know.
I'd like to understand how should I validate a given named id for a generic entity, like, say, an email login, just like Yahoo, Google and Microsoft do.
I mean... If you do have an user named foo, trying to create foo2 will be denied, as it is likely to be someone trying to mislead users by using a fake id.
Coming to mind:
Levenshtein Distance
Hamming Distance
You're going to have to take a two pass approach.
The first is a potential RegEx expression to validate that the entity name meets your specifications as much as possible. For example, disallowing certain characters.
The second is to perform some type of fuzzy search during the name creation. This could be as simple as a LIKE '%value%' where clause or as complicated as using some type of full-text search and limiting hits to a certain relevance rating.
That said, I would guess the failure rate (both false positives and false negatives ) match would be high enough to justify not doing this.
Good luck.