[Tutor] converting decimals to fractions

[Kirby Urner]

Probably easier to calculate on the fly, vs. do a
lookup table.

One algorithm is:  take the decimal part of n and
convert it to the nearest x/32.  Then reduce x/32 to
lowest terms by dividing x, 32 by their gcd (greatest
common divisor).

   def div32(n):
       "x for closest x/32"
       return round((n-int(n))*1000/32.)

   def gcd(a,b):
       "Euclidean Algorithm (recursive form)"
       if b==0: return a
       else: return gcd(b,a%b)

   def mkinch(n):
       numer  = div32(n)
       thegcd = gcd(numer,32)
       return "%s %s/%s" % \
              (int(n),int(numer/thegcd),int(32/thegcd))

   >>> mkinch(1.133)
   '1 1/8'
   >>> mkinch(1.185)
   '1 3/16'
   >>> mkinch(1.1)
   '1 3/32'

Since writing this, I've seen Tim's.  His is no doubt
faster, as it takes advantage of the base 2 aspect of
your problem thru bit shifting.

Kirby