I am studying my first year in Programming and I have a slight problem in relation to Visual Basic coding. I know this sounds slightly vague, however I just wish to find out whether i need to create a variable, array or function.
I am creating a website app which processes a mobile phone order. I have designed a form which includes the quantity of mobile phones a particular customer requires, and the type of mobile phone the customer wishes to order.
I have included quantity values from 1-5 and 5 different types of mobile phones. I also have a button 'Process Order'. I just want to know how i can assign a particular type of mobile to the quantity.
In other words a calculation function where if I click process order, a price will be displayed showing exactly how much it costs for the phone + quantity needed. I have included a combo box with the list of phone types and the prices of each phone.
I want to be able to create a code which links a phone to a quantity for example Qty: 2 Type: superphone (costing £45). Once i process the order I should see a total price of £90. I am not expecting anyone to do it for me, just a simple explanation of what i need to look at in order to figure out the coding :)
It sounds like you are searching for the Dictionary class.
A dictionary matches some input (called key) to an output (called value). In principle, the same can be achieved through a function but a dictionary is more concise, can be changed at runtime, and may also be more efficient.
Conceptually, an array is just a specific type of dictionary that maps the input values 0 – n (its indices) to the indexed values.
Example:
Dim phonePrices As New Dictionary(Of String, Decimal)()
phonePrices.Add("Nookia", 12.30)
phonePrices.Add("Motolola", 12.12)
phonePrices.Add("THC", 42.00)
These prices can then be looked up by using the indexer:
Dim priceOfMyNookia = phonePrices("Nookia")
Related
My laravel app is a big family tree website. I have Person records (id, first, last, DOB, parent_family_id, etc) and Family records (id, caption, mother_id, father_id, original_bool).
Everything's done now except for my last challenge: an outline view! I have a number of 'original families' (the earliest ones), and for each of them I'd like to be able to display their descendants all the way down to present day in an outline form (kids, those kids' families, those families' kids, etc).
So far I've written a few functions in the relevant controller:
get_kids_of_family($family)
get_families_person_made($person)
get_descendants($family, $results)- this will be a recursive function that calls get_kids_of_family, adds them to a results set (some gigantic array that I'll pass along?), then for each of them it calls get_families_person_made, adds them to the results set, calls get_descendants on each of those families, etc.
Then it occurred to me: even if I can get this working, it'll be crunching around through a lot of data, and it rarely changes (weekly/monthly at most, with the discovery of a new person). Therefore I'm wondering if it makes sense to make/run a script to save the results someplace (like an xml or json file) and then somehow pass that file to my view for display.
Thoughts? What's a good (but not too advanced) way to implement something like this in a laravel app?
Thanks in advance for your help!
I'd like to store phone numbers as unique user ids in my database/app which will initially roll out in the United States but could expand to other countries eventually.
My question is when storing phone numbers, what's a resilient way to store the number as a string so that I don't have any duplicate numbers from other countries overlap.
My initial thought is to do it this way
+1(212)555-5555
+{countryCode}({areaCode}){{subscriberCode}} *formatted with a hyphen for u.s numbers
Does that seem reasonable or are there any pitfalls to that? Should spaces be used? For instance I can't imagine other countries would use spaces or parenthesis in their subscriber codes... but maybe they do? It would also be nice if it followed the standard output format from ios and android phones' address books.
Here's what I'd say:
Use the plus. It indicates for certain that the country code follows and the number is not in a local format. You could also not store the plus and make an internal decision that all phone numbers will be stored with the country code, thus obviating the need for the plus.
Don't use any formatting in the storage of the number. Formatting is irrelevant when it comes to dialing and it makes searching and comparing more difficult.
Use a gem like phony_rails or phoney to format the number to local conventions when displaying.
So it looks like there is an international standard
http://en.wikipedia.org/wiki/E.164
And a node.js library that can format to that standard
https://github.com/aftership/node-phone
I'm implementing a native iOS application, which provides a feature to search for articles using keywords and several search filters such as author, year, publisher etc. Each of these search filters has several options such as 2014, 2013, and 2012 for the year filter, or Academe Research Journals, Annex Publishers, and Elmer Press for the publisher filter. Each of these options has a BOOL stating whether the option is selected or not. I need an object that wraps the search keywords and search filters so that I can send it to the server, which is responsible for the search operation.
Which data structure should I use to represent these search filters in the wrapper class?
Something like XML comes to mind:
<year>2014</year>
<publisher>Annex Publishers</publisher>
Although I find it rather bulky. I'd probably prefer something like:
year=2014|publisher=Annex Publishers
You'll need to escape = and | appearing in the field names or values, but this is easy to do.
This could just be a single string sent across.
In terms of actual data structures, you could have a map of field name to value, only containing entries where the option is selected. Or you could have a class containing pointers / references for each field, set to null if the option is not selected.
Another totally different consideration is to use an enumerated type, i.e. mapping each possible value to an integer, typically resulting in less memory used and faster (and possibly more robust) code, depending on how exactly this is done.
You could map it as follows, for example:
Academe Research Journals 0
Annex Publishers 1
Elmer Press 2
Then, rather than sending "Annex Publishers" as publisher, you could just send 1.
year=2014|publisher=1
The extension for multiple possible values for a field can be done in various ways, but it's fairly easy to do:
<year>2014</year>
<year>2013</year>
<publisher>Annex Publishers</publisher>
Or:
year=2014,2013|publisher=Annex Publishers
I've read somewhere (can't remember/find where) an article about web usability describing when to use drop downs and when to use autocomplete fields.
Basically, the article says that the human brain cannot store more then the last five options presented to choose.
For example, in a profile form, where there is your current occupation, and the system gives you a bunch of options, when you read the sixth options, your brain can't remember the first one anymore. This example is a great place to use an autocomplete field, where the user types something that he thinks that would be his occupation and then select the better from the few options filtered.
I would like to hear your opinion about this subject.
When should I use a drop-down and when I should use a Autocomplete field?
For a limited list, don't use an autocomplete edit box or combobox, but use a listbox where all values are visible all at once. For limited lists, especially with static content of up to about 8 items, this takes up real estate, but presents the user with a better immediate overview.
For less than 5 items a radiogroup or checkbox group (multiple selections) may also be better.
For lists whose content is dynamic, like a list of contacts, a (scrolling) listbox or combobox are appropriate because you never know how many items will be in the list. To keep it manageable, you will need to allow for some kind of filtering and/or autocomplete.
Autocomplete usually suffers from the fact that what the users types needs to match a string from the beginning. I hate those except for when they are used to complete a value based on what I typed in that (type of) field before. E.g. what browsers nowadays offer when filling out online forms.
Allowing a user to start typing in a combobox usually suffers the same drawback. But admittedly it doesn't need to if the filtering is based on "like %abc%" instead of "starts with abc"
When dealing with lists that can have many similar items, I really like the way GMail's "To" field handles it. You start typing any part of someone's name or e-mail address and GMail will drop down a list presenting all the contacts whose name or e-mail address contains the characters you have typed so far anywhere within them. Using the up and down keys changes the selection in the dropped down list (without affecting what you have typed) and pressing enter adds the currently selected item to the "To" field. By far the best user experience I have had so far when having to select something from a list.
Haven't found any components yet that can do this, but it's not too hard to "fake" by combining an edit box and a listbox that drops down when you start typing and has its contents is filtered based on what has been typed so far.
I would use 2 criteria,
1) How long is the list, if the list contains 5 elements you better use a combobox as it will be easier for the user (better UX)
2) In case the list is long, how easy for the user to remember the prefix of what he/she is looking for... if it's not easy, using autocomplete is irrelevant..
I'd say it depends on the diversity in the list, and the familiarity with the list items.
If for example the list contained over 5 car brands (list items I'm familiar with), no problem.
If on the other hand the list has over 5 last names, it could take me some more time before I'd make a selection.
You should probably just try out both options and trust your gut on which you find easier to use.
Here's the opposite approach:
The worst time to use an auto-complete box is when you have a finite and relatively small set of options, and the user doesn't know the range of valid options. For example, if you're selling used cars and you have a mixed bag of brands, simply listing the brands in a combobox is more efficient and easier to browse than an auto-complete method.
Being able to remember the last 5 options is most likely irrelevant unless you have a giant list of options and are requiring the user to select the most relevant item.
An alternative approach is to use both. I believe Dojo has a widget that acts as both a combobox and an auto-complete field. You can either choose to start typing and it will narrow down the possible options, or you can interact with it with your mouse and browse it like a combobox.
I usually look at how big the list is going to be. If there are going to be more than 15 options then it just seems easier to find if they can just start typing.
The other circumstance for me is when there is an other option and they can free type it. This essentially eliminates the need for two controls since you can combine in one.
The main difference has nothing to do with usability but more to do with what defines the acceptable inputs.
You normally use a ComboBox when you have a predefined list of acceptable inputs (e.g. an Enum or list of occupations).
An auto-complete field is best used when there are many known inputs BUT custom input is accepted as well. The user will become frustrated if they type "Programmer" in as their occupation but it wasn't one of the pre-defined, acceptable inputs, and they are given a message that their input is not valid.
Keep in mind that ComboBoxes do allow you to type in them to select the first matching option. Some types of ComboBoxes (depending on the UI framework you are using) even allow free-form text fields at the top or side of the field to search or add to the list.
Of coarse the best way to determine what YOUR user will prefer is testing: A/B, field, user, etc.
Hope this helps you solve your dilemma!
Our application displays tons of valuable information to our users in a table. We have a filtering capablity that is based on boolean/logic searches. Even after coaching, users still tend to not understand how to use filters because AND OR > >= etc are foreign to them. This filter is easy for programmers since it is easily translated into code. Any examples on how this can be made more user-friendly and less prone to error?
In the past, when I needed to solve this problem, I presented the users with a list of items (in one or more columns), and gave them a single text box to type text into. I would then match the text against the text in the columns, and collapse the list (removing records that do not match) as they type.
This approach reminds users of Google. Everyone knows how to Google.
If you don't like the idea of presenting a large list of all items initially, you can show an empty results pane first, and display results after a search is typed in.
Convert operators to plain English text and ask them to select from it.
For eg: To
Show me all Books whose author is [text field] and the price is [less than/greater than] [text field]
[less than/greater than] is a dropdown list
[text field] is an input box
The resulting text after the user has filled in all the fields should result in plain simple English
Eg: Show me all books whose author is Stephen King and the price is less than 10 $
I used this in an app of mine when I used to freelance and the users loved it.
Using some nifty UI programming you can give options to expand the filter to n levels.
In web applications, telerik had a good idea with their grid, you should be able to do that in desktop applications too.
you can provide some preset filters for the most common queries to that table - if that's possible with the application you are using
you can provide a "count instead of display" mechanism so the user sees how many rows he/she will potentially retrieve
you can provide them a Wiki page with some examples online
you can give them a QBE tool
hope that helps
good luck MikeD
In my experience you are simply not going to get end users to understand the difference between AND and OR conditions. Therefore I build my filters so that ANDing or ORing is built in. In general, my logic is as follows:
Criteria for different fields are ANDed together to restrict results.
Multiple values for the same field are effectively ORed together and then ANDed onto the criteria for other fields. I generally detect input into a single field of comma-separated lists (translated to IN ()), dash-separated ranges (translated to BETWEEN), wildcard values (translated to LIKE), and any combination (for example Customer ID: 1-10, 50, 52).
I find that most users intuitively understand this system.
Of course, from time to time a different interface with some degree of ORing is required and in those cases I generally have a section of the search user interface in a panel or group box labelled "Any of these is true".
I have recently been working on this problem. My solution is to be more descriptive, to use words instead of symbols and to change the words where it allows for a more readable layout. To illustrate, imagine the filter expression:
Breed == "Spaniel" AND (Age == 2 OR Colour == "White")
Certain linear Query builders might write this:
( And/Or Field Operator Value
[ ] [Breed] [=] [Spaniel]
[1] [AND] [Age] [=] [2]
[1] [OR] [Colour] [=] [White]
Or a hierarchical one may display this as:
AND
[Breed] [Is Equal To] [Spaniel]
OR
[Age] [Is Equal To] [Spaniel]
[Colour] [Is Equal To] [White]
Both of which might be readable to a developer but not so readable to the layperson.
My solution is more like:
Show ALL records where
[Breed] [Is Equal To] [Spaniel]
Show ANY records where
[Age] [Is Equal To] [Spaniel]
[Colour] [Is Equal To] [White]
So borrowing from the hierarchical approach but changing the AND and OR to an ALL or ANY. This means it can be read from top to bottom a little more easily.
I think Django's built-in admin interface has a very intuitive UI for filters.
There's a simple screenshot in the docs but there's a lot more you can do, especially when filtering on dates.
You might want to take a closer look at Django's admin interface to see if you can apply some of their tricks to your case.
I would think something similar to MS Access Query generator. You may also want to have good context sensitive help system that will guide first time users.
Theresa Neil illustrated several approaches for building complex rule interfaces (AKA predicate clauses) in the iTunes Solves the Nested Clause Dillema post. Some good examples there. I really like the way Apple does it in iTunes (although, I don't use iTunes).