[Tutor] Projects (fwd)

[Ricardo Aráoz]

Tiger12506 wrote:
>> 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
> 
> This could be written much more efficiently. It can be done with only these 
> lists~
> ones = 
> ['zero','one','two','three','four','five','six','seven','eight','nine']
> teens = 
> ['ten','eleven','twelve','thirteen','fourteen','fifteen','sixteen','seventeen','eighteen','nineteen']
> tens = 
> ['','','twenty','thirty','fourty','fifty','sixty','seventy','eighty','ninety']
> hundstr = 'hundred'
> thousand = 'thousand'
> 

Isn't dictionary access faster than list access? Why are three lists
'much more efficient'?