python - 2D Numpy Array Beginner troubles -

my issues trying work arrays each elements tuple of 2 values.

specifically problem generate random 2-dimensional walk of 200 (but testing 2) steps max distance, 100 (try 2) of walks per stage, , commencing each stage @ largest distance origin of previous stage.

i can generate array of random steps , them return final position (x,y) value , calculate distance of them origin of each walk:

that's defined in these functions:

#............................................................getpositioninteger def getposint(description) :     """asks user enter positive integer"""     askagain = false     while askagain == false:         try:             posint = eval(raw_input("\n %s :  " %description))             assert 0 < posint , "not positive integer"             assert type(posint) == int , "not positive integer"             askagain = true         except :             print "input failed, not positive integer"     return posint #...............................................................initialposition def initialposition() :     """initial position of walker @ start of random walk"""     return (0.0, 0.0)  #......................................................................distance def distance(posa, posb) :     """distance between 2 positions"""     xi = posa[0] ; yi = posa[1]     xf = posb[0] ; yf = posb[1]     return np.sqrt((xf-xi)**2+(yf-yi)**2)      #..................................................................getpositions def getpositions(start, nsteps, maxstep):     xarray = maxstep * np.random.random(nsteps+1)* np.cos(2.0 * np.pi * random.random())     yarray = maxstep * np.random.random(nsteps+1)* np.sin(2.0 * np.pi * random.random())     xarray[0] = start[0]     yarray[0] = start[-1]     xarray = np.cumsum(xarray)     yarray = np.cumsum(yarray)                                                         return (xarray[-1], yarray[-1]) 

but can't array of final position of each walk per stage in (x,y) form per stage

here's main script , i'm having trouble:

import numpy np import matplotlib.pylab plt import random import time  max_step_size = 0.90    # maximum size of single step [m] random.seed(12345)  #..........................................................................main def main ():     ''''''     print "random walk in stages in 2 dimensions"     userdata = getdetails()     print "\nplease wait while random walks generated , analyzed..."     num_stages = userdata[0]     num_walks = userdata[1]     num_steps = userdata[2]     stagestart = initialposition()     stage in np.arange(num_stages):         walks = np.zeros((num_walks, num_walks), dtype=np.ndarray)         walk in walks:             walk = getpositions(stagestart, num_steps, max_step_size)             print walk         print walks 

you see i'm having trouble making (x,y) style array, [0 0] should [0.0 , 0.0] , printed twice , additionally, not changing final position.

i appreciate , help, advice or references can provide. -sid