I really don't get why this python 3.2 code doesn't work:
file = open("evil2.gfx","rb")
tmp = bytearray(file.read())
file.close()
tmp1 = b''
tmp2 = b''
tmp3 = b''
tmp4 = b''
tmp5 = b''
result = b''
for i in range(0,len(tmp)):
    if i%5 == 0:
        tmp1 += bytes(tmp[i])
    elif i%5 == 1:
        tmp2 += bytes(tmp[i])
    elif i%5 == 2:
        tmp3 += bytes(tmp[i])
    elif i%5 == 3:
        tmp4 += bytes(tmp[i])
    elif i%5 == 4:
        tmp5 += bytes(tmp[i])

I really don't understand why I can't add a single byte from a bytestring to a bytestring without typecasting, and if I try to convert it like above with bytes() I get very long bytestrings only containing null
Is the typesystem of Python really that much more difficult than that of C or do I just not understand it yet?