Turn Python trace Walk DEMO

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#quote from ' Introduction to computation and programming #using Python, revised, MIT Press ' import Randomimport Pylab def s        Tddev (x): mean = SUM (x)/len (x) tot = 0.0 for X in X:tot + = (X-mean) **2 return (Tot/len (x)) **0.5        def CV (x): mean = SUM (x)/len (x) return StdDev (x)/mean class Location (object): Def __init__ (self, x, y):  "" "X and Y is floats" "" self.x = x self.y = y def move (self, deltax, DeltaY): "" "DeltaX And DeltaY is floats "" "Return location (self.x + deltax, Self.y + deltay) def GetX (self): retur        n self.x def GetY (self): return self.y def distfrom (self, other): Ox = other.x Oy = other.y Xdist = Self.x-ox ydist = Self.y-oy return (xdist**2 + ydist**2) **0.5 def __s Tr__ (self): return ' < ' + str (self.x) + ', ' + str (SELF.Y) + ' > ' class Field (object): Def __init __ (self): self.drUnks = {} def adddrunk (self, Drunk, loc): If Drunk in self.drunks:raise valueerror (' Duplicat E drunk ') else:self.drunks[drunk] = loc def movedrunk (self, drunk): if drunk not In Self.drunks:raise valueerror (' Drunk not in field ') xdist, ydist = Drunk.takestep () currentloc ation = Self.drunks[drunk] #use Move method of location to get new location self.drunks[drunk] = Currentloca Tion.move (Xdist, ydist) def getloc (self, drunk): If drunk not in Self.drunks:raise Valueerro R (' Drunk Not on field ') return Self.drunks[drunk] class Drunk (object): Def __init__ (self, name = None            ): "" "Assumes name is a str" "" Self.name = name def __str__ (self): if self! = None: Return self.name return ' Anonymous ' class Usualdrunk (Drunk): def takestep (self): stepchoices = [(0.0, 1.0), (0.0,-1.0), (1.0, 0.0), ( -1.0, 0.0)] return Random.choice (Stepchoices) class Colddrunk (Drunk): def takestep (self): Stepchoices = [(0.0, 1.0), (0.0, -2.0), (1.0, 0.0), ( -1.0, 0.0)] return Random.choice (stepchoices) class E Wdrunk (Drunk): def takestep (self): stepchoices = [(1.0, 0.0), ( -1.0, 0.0)] return Random.choice (stepchoic            ES) class Styleiterator (object): Def __init__ (self, styles): Self.index = 0 Self.styles = Styles            def nextstyle (self): result = Self.styles[self.index] if Self.index = = Len (self.styles)-1:    Self.index = 0 Else:self.index + = 1 return result def tracewalk (Drunkkinds, numsteps): Stylechoices = Styleiterator (' B + ', ' r^ ', ' Mo ')) F = Field () for dClass in drunkkinds:d = DClass () F. Adddrunk (d, location (0, 0)) locs = [] for s in range (numsteps): F.movedrunk (d) Locs.ap       Pend (F.getloc (d)) Xvals = [] Yvals = [] for L in Locs:xVals.append (L.getx ()) Yvals.append (L.gety ()) CurStyle = Stylechoices.nextstyle () pylab.plot (xvals, Yvals, curstyle, label = Dclass.__name  __) Pylab.title (' spots visited on Walk (' + str (numsteps) + ' steps) ') Pylab.xlabel (' Steps east/west of origin ') Pylab.ylabel (' Steps North/south of origin ') pylab.legend (loc = ' best ') tracewalk ((Usualdrunk, Colddrunk , Ewdrunk), Pylab.show ()

　　

Turn Python trace Walk DEMO