mrange 模拟 系统 range

def mrang(start,end=0,step=1):
    (start,end) = start>end and (end,start) or (start,end)
    #print (start,end)
    m = []
    while start < end:
        m.append(start)
        start+=step
    return m


print mrang(5),range(5)
print mrang(1,5),range(1,5)
print mrang(4,5,2),range(4,5,2)

'''
[0, 1, 2, 3, 4] [0, 1, 2, 3, 4]
[1, 2, 3, 4] [1, 2, 3, 4]
[4] [4]

'''