Ah, nice! Thank you! Sseeing the formal rules makes it easier:
http://www.diveintopython.net/unit_testing/stage_5.html
A regex is used to test whether the roman numeral is valid. Very elegant!
Regards,
Albert-Jan
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
All right, but apart from the sanitation, the medicine, education, wine, public
order, irrigation, roads, a
fresh water system, and public health, what have the Romans ever done for us?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>________________________________
> From: Evert Rol <[email protected]>
>To: Albert-Jan Roskam <[email protected]>
>Cc: Python Tutor <[email protected]>
>Sent: Monday, February 27, 2012 5:42 PM
>Subject: Re: [Tutor] roman to arabic
>
>> I wrote a little program that does the conversion (I won't post it because
>> it would be a spoiler for the OP). The one thing I don't know, though, is
>> how to formalise
>> that it is not allowed to write something like IIIIIIIIX, but instead just
>> II. Or not DM but simply D. The rule is to write it the shortest possible
>> way. Am I wrong or is it really not trivial at all to write an error class
>> for such lengthy roman numerals?
>
>Mark Pilgrim wrote whole sections on Roman numerals in his Dive Into Python
>tutorial. While the numerals pop up in various examples throughout the
>chapters of the tutorial, for this, the tutorial on unit testing may proof
>helpful: http://www.diveintopython.net/unit_testing/romantest.html
>Somewhere in that example, there's unit testing code just for examples as
>above. From the unit test, follow the tutorial into chapter 14 to see how it's
>done.
>
>Hope that helps,
>
> Evert
>
>
>
>>
>> Regards,
>> Albert-Jan
>>
>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> All right, but apart from the sanitation, the medicine, education, wine,
>> public order, irrigation, roads, a
>> fresh water system, and public health, what have the Romans ever done for us?
>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> From: Alan Gauld <[email protected]>
>> To: [email protected]
>> Sent: Monday, February 27, 2012 4:37 PM
>> Subject: Re: [Tutor] roman to arabic
>>
>> On 27/02/12 14:41, Cranky Frankie wrote:
>>
>> > <<A quote worth mentioning here is: "If you need more than 3 levels
>> > of indentation, you're screwed
>> >
>> > I've always wondered about this quote. I'm thinking it means you might
>> > want to have functions or subroutines, depending on the language, to
>> > do big chunks of logic,
>>
>> That's one option.
>>
>> The OP also had the option of using a lookup table(dictionary)
>> or just using elifs instead of nested ifs.
>>
>> Often a different algorithm helps.
>>
>> Also functional programming (ie. not just procedural!) can reduce the
>> numbers of indentation levels. (See the FP topic in my tutor for some
>> examples of this.)
>>
>> Simple hiding of indentation levels inside a function is kind of
>> the last resort in reducing indentation levels. Generally deep indentation
>> reveals problems in the basic algorithm and/or
>> data structures.
>>
>> > offers almost unlimited indentation, so it's up to the programmer to
>> > not use it?
>>
>> Correct, this is a program design decision not a language feature.
>>
>> -- Alan G
>> Author of the Learn to Program web site
>> http://www.alan-g.me.uk/
>>
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>
>
>
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