Danny Yoo wrote:
> Hi Jason,
>
>
> Looking back at that Java code:
>
> ////////////////////////////////////////////////
> static String convertDigitToEnglish(int d) {
> switch ( d )
> {
> case 1: return "one";
> case 2: return "two";
> case 3: return "three";
> case 4: return "four";
> case 5: return "five";
> case 6: return "six";
> case 7: return "seven";
> case 8: return "eight";
> case 9: return "nine";
> default: return "\nFatal Error!\n"; // should I abort pgm?
> } // end of switch
> } // end of convertDigitToEnglis
> ////////////////////////////////////////////////
>
>
> Frankly, this seems silly to me. First, it ignores zero, which is a cardinal
> sin. I'm being somewhat serious about this: functions should do what they
> say,
> and that function isn't.
>
>
> But the code could also be written much more tightly as:
>
> ////////////////////////////////////////////////
> static String digitToString(int n) {
> String[] words = {"zero", "one", "two", "three", "four",
> "five", "six", "seven", "eight", "nine"};
> if (0 <= n && n < 10) {
> return words[n];
> }
> throw new IllegalArgumentException("input not a single digit");
> }
> ////////////////////////////////////////////////
>
> I don't mean to make this post so Java-centric; it just seems a little unfair
> to compare a bad Java routine to a good Python routine. :) Writing an
> equivalent in Python is also pretty straightforward:
>
> #################################
> ## Pseudocode: just a sketch
> def digitToString(n):
> words = ["zero", "one", ...]
> if 0 <= n < 10:
> return words[n]
> ...
> #################################
>
> Like dictionaries, the list data structure works pretty well for key/value
> lookup if the input key is a small number.
>
>
> Good luck!
>
up to a thousand (not tested)
words = {0:'zero', 1:'one', 2:'two', 3:'three', ... , 10:'ten',
11:'eleven', 12:'twelve', ..., 19:'nineteen',
20:'twenty', ...., 90:'ninety', 100:'one hundred' }
def digitToString(n) :
try :
retStr = words[n]
except KeyError :
if n > 100 :
retStr = (digitToString(n // 100)
+ ' hundred and '
+ digitToString(n % 100))
else :
retStr = (digitToString(n - (n % 10))
+ ' '
+ digitToString(n % 10))
return retStr
HTH
_______________________________________________
Tutor maillist - Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor
