Programming performance/hay.steve Python

• Implementation time: 1.5 hours.
• Experience: 3 days.
• Comments: I spent most of my time noodling on the syntax of Python and familiarizing myself with the documentation. I also spent some time getting the heap to work instead of taking multiple passes with that data. I originally said it took 2 hours, but I am bringing it down to 1.5 because I was eating dinner while and watching a movie while coding. Also, I came back later and spent a few minutes adding a verbosity feature as suggested in the problem statement.

Code

<code-python> from heapq import heappush, heappop, nsmallest

verbose=False filename = "gspc.txt"

days = []

for f in open(filename):

       if f[0] == '#':
               continue
       linelist = f.split(' ')
       heappush( days, linelist )

cash = 10000.00 previousClose = -1.0 currentClose = 0.00

shares = []

beginningBalance = cash

print "Beginning Balance:", cash while days != []:

       day = heappop( days )
       i = day[0]
       currentClose = float( day[4] )

       if previousClose != -1.0:
               percentGain = ( currentClose - previousClose ) / previousClose
               if percentGain < -0.03:
                       numShares = 0.1 * cash / currentClose
                       heappush( shares, (currentClose, numShares) )
                       cash = 0.9 * cash
                       if verbose: print "On", i, ", bought" , numShares , "shares at" , currentClose , "."

               else :
                       while shares != [] and nsmallest(1, shares)[0][0] <= currentClose / 1.06:
                               sell = heappop( shares )
                               cash += sell[1] * currentClose
                               if verbose: print "On", i, "sold" , sell[1] , "shares at" , currentClose , "."

       previousClose = currentClose

while shares != []:

       sell = heappop( shares )
       cash += sell[1] * currentClose
       if verbose: print "Sold" , sell[1] , "shares at" , currentClose , "."

print "Beginning balance:", beginningBalance print "Ending balance:", cash print "Percent Gain:", (cash-beginningBalance)/beginningBalance*100, "%." </code-python>

--Hay.steve 01:53, 8 March 2007 (UTC)