import random
import array
import numpy
from timeit import Timer

numlines = 500
numcols = 120
#build numlines line, numcols column list on which to operate.
#Could do this in one line with nested comprehensions
random.seed()
a = []
for i in range(0,numlines):
    a.append([x * random.randint(0,500) for x in range(1,numcols)])

#Now build list of arrays.
#Can't use list comprehensions because lines are arrays too
#Can't use 2d array because arrays can only hold base types?
b = []
for i in range(0,numlines):
    l = array.array('i')
    for x in range(1,numcols):
        l.append(x * random.randint(0,500))
    b.append(l)

#easier with numeric
c = numpy.ones( (numlines,numcols) )
for x,l in enumerate(c):
    c[x] = map(lambda line: random.randint(0,500),l)

def not70(x):
    if x == 70:
        return 0
    else:
        return x
    
def replaceList(a):
    """loop through 2d list with for loop, using map to find and replace
    values in lines of array"""
    for index, line in enumerate(a):
        a[index] = map(not70, line)

def letsUseALittleMath(a):
    b = numpy.not_equal(a, 70)
    a = a * b
	
#quicker way?
def fastway(a):
	a[a==70]=0

	
if __name__=='__main__':
    from timeit import Timer
    reps = 500
    t = Timer("replaceList(a)", "from __main__ import replaceList, a")
    print "Time using all lists: %s " % t.timeit(reps)
    t = Timer("replaceList(b)", "from __main__ import replaceList, b")
    print "Time using lists of arrays: %s" % t.timeit(reps)
    t = Timer("letsUseALittleMath(c)", "from __main__ import letsUseALittleMath, c")
    print "Time using Numpy arrays and array multiplication: %s" % t.timeit(reps)
    #t = Timer("replaceList(c)", "from __main__ import replaceList, c")
    #print "Time using Numeric arrays: %s" % t.timeit(reps)
    t = Timer("fastway(c)", "from __main__ import fastway, c")
    print "Time using fastway: %s" % t.timeit(reps)