Library to determine indefinite article of a noun?

Question

Are there any libraries for .NET that deal with determining the Indefinite Article of a noun?

My crude attempt is below, which will probably work for 99% of my usage (which is acceptable) just wondering if there are any established alternatives?

public static string GetIndefinateArticle(string noun)
{
    if(string.IsNullOrEmpty(noun))
        return noun;

    var first = noun[0];

    if(first == 'a' ||
        first == 'e' ||
        first == 'i' ||
        first == 'o')
        return "an " + noun;

    return "a " + noun;
}

Update: Eamon pointed out a duplicate question in the comments: How can I correctly prefix a word with "a" and "an"? I'll leave this Q here and open though, because I still don't really have an answer.

According to Grammar Girl, The use of Indefinite Article is based on the sound of the noun, Worth note it here, i think. http://grammar.quickanddirtytips.com/ — Jhonny D. Cano -Leftware-, Apr 06 '10 at 13:23
yeah i realise this, but determining the sound from ascii is rather difficult! Hence wondering if there are any libs which presumably check for common starting letter combinations grouped based on their sound? — Andrew Bullock, Apr 06 '10 at 13:24
`self`? is that a synonym for `this`? or what is that? should it have been `noun`? — Svish, Apr 06 '10 at 13:54
in some programming languages it's called "self", in some "this". It's the same thing. — lugte098, Apr 06 '10 at 14:41
See also: http://stackoverflow.com/questions/1288291/how-can-i-correctly-prefix-a-word-with-a-and-an — Eamon Nerbonne, Jan 31 '12 at 13:56
I've implemented an actual lirary since this question was asked; see http://eamon.nerbonne.org/2013/04/a-vs-determine-appropriate-english.html or use nuget and install AvsAn. — Eamon Nerbonne, May 24 '13 at 10:50

score 7 · Answer 1 · answered Apr 18 '10 at 09:49

7

If this is something you need done seriously, you may consider porting the Ruby Linguistics (English) library to .Net. It's open source & does a pretty good job of calculating the correct articles.

http://deveiate.org/projects/Linguistics/

answered Apr 18 '10 at 09:49

Mark McDonald

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+1 for answering the question (is there a library) rather than cobbling together some code. – Kirk Broadhurst Apr 18 '10 at 10:29
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Seeing as IronRuby has just been released, there may be no need to port! I shall play tomorrow. Thanks – Andrew Bullock Apr 18 '10 at 20:51

score 5 · Answer 2 · edited Nov 05 '17 at 23:20

5

Since all you're really doing is check for patterns in the string, you could use a regular expression. This should also allow for future expansion of letter combos like lutge098 talked about:

public static string GetIndefinateArticle(string noun)
{
    if (Regex.IsMatch(noun, "^([aeio]|un|ul)", RegexOptions.IgnoreCase))
        return "an " + noun;
    else
        return "a " + noun;
}

edited Nov 05 '17 at 23:20

TheSoftwareJedi

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answered Apr 06 '10 at 14:10

CAbbott

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It will be a long and difficult regex probably, but more effective – lugte098 Apr 06 '10 at 14:42
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@lugte You haven't seen a long and difficult regex until you've seen the proper way of validating an email address. It was **over 6 lines long!** – Earlz Apr 18 '10 at 09:55
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@Earlz If you put it that way, i guess i haven't :D – lugte098 Apr 19 '10 at 07:23

Eamon Nerbonne · Answer 3 · 2016-05-09T14:06:45.933

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I implemented a library to do this: https://github.com/eamonnerbonne/a-vs-an; it's AvsAn on nuget. It's based on real usage patterns in wikipedia and hence even deals well with tricky things like...

"an 0800 number"
"an ∞ of oregano"
"a NASA flight"
"an NSA analyst"

In other words, it usually even will deal reasonably with many things that aren't normal words.

edited May 09 '16 at 14:06

answered Mar 30 '13 at 16:24

Eamon Nerbonne

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score 2 · Answer 4 · edited May 23 '17 at 12:01

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I've ported a function from Python that correctly determines vowel sounds in C# and posted it as an answer to the question Programmatically determine whether to describe an object with a or an?. You can see the code snippet here. It is indeed more complicated than just looking at vowels.

edited May 23 '17 at 12:01

Community

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answered Nov 08 '11 at 01:04

Stuart

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score 0 · Answer 5 · edited Apr 06 '10 at 13:50

0

What i would do is:

var first = noun[0];
var second = noun[1];

if(first == 'a' ||
    first == 'e' ||
    first == 'i' ||
    first == 'o')
    return "an " + self;

if(first == 'u')
    if (second == 'n' ||
        second == 'l')
        return "an " + self;

if(first == 'h')
    if (second == 'i')
        return "an " + self;

return "a " + self;

So you can define some cases where some letters in combination with each other form a certain sound. Hope this helps.

edited Apr 06 '10 at 13:50

Andrew Bullock

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answered Apr 06 '10 at 13:43

lugte098

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Your `if` statement for `h` is very wrong. It would produce `an hit` and `a honor`, both of which are incorrect. – Apr 06 '10 at 14:25
Are you familiar with a control statement called `switch`? – ANeves Apr 06 '10 at 14:37
@Matthew Ferreira: keep in mind that this is just an example of concept. – lugte098 Apr 06 '10 at 14:44
2

The h is an unsolvable problem without a dictionary. Make your program speak Cockney, they always have a silent h so you can always pick "an". – Hans Passant Apr 06 '10 at 15:19
I think that the question itself is unsolvable. Many words also have multiple pronunciations which are valid. – Apr 06 '10 at 15:20
@Matthew Ferreira yeah i appreciate its probably very difficult to solve completely for this reason, however i'll willingly accept a solution that works most of the time, was just looking for the best way to achieve "most" – Andrew Bullock Apr 06 '10 at 15:34
The 'u' solution is also incorrect - you will end up with *an uniform* and *a umbrella*. Like i mentioned in my answer there are a lot of complexities to look for, which can make your code a bit of a beast. – slugster May 04 '11 at 08:22

score 0 · Answer 6 · edited May 04 '11 at 01:56

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The basic rule of "a" before a consonant and "an" before a vowel gets you most of the way there, that would be very easy to implement. The problem is the "sounds-like a vowel = an" case -- that would be much harder.

edited May 04 '11 at 01:56

Joel Spolsky

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answered May 04 '11 at 01:52

debracey

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score 0 · Answer 7 · answered May 04 '11 at 01:53

No, and it isn't as simple as just whacking an extra n when the next character is a vowel. There are a whole bunch of subtleties around it, and you also have to consider how to handle h - some use an before it, some don't.

This is also English specific, and the framework is relatively language agnostic.

This means you will have to cook it up yourself :)

Library to determine indefinite article of a noun?

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