Move all 0s to the front in an array of 1s and 0s

gistfile1.py

def solve(a):
    lastNonZeroPos = -1

    for x in range(0, len(a)):
        
        # if the lastnonzeropos isn't set, and this is nonzero
        if lastNonZeroPos < 0 and a[x] != 0:
            # set the last non zero pos
            lastNonZeroPos = x

        # else if this is a zero and lastnonzero has been set
        if lastNonZeroPos >= 0 and a[x] == 0:
            # swap this position with the last non zero
            temp = a[x]
            a[x] = a[lastNonZeroPos]
            a[lastNonZeroPos] = temp

            # increment the lastnonzeropos (cause you know the one to the right of it is nonzero)
            lastNonZeroPos += 1

#        print a, lastNonZeroPos

    print a

solve([0,1,0,1,0,1,1,0])
solve([1,0,1,0,1,1,0])
solve([0,1,0,1,0,1])
solve([0,1,0,1,0,1,0])
solve([0,1,0,1,0,0,0,1,0])
solve([1,1,1,1,1,1,0,0,0,0,0])
solve([1,1,1,1,0,0,1,0,0,1,1,1,0,1,0,0,0,1,0,1])