Error i not defined in for loop using python -

i have 1 array 'barray' of size 'bsize' , 'carray' of size 'csize'. i loop barray , j loop carray.

i error not defined. want loops go 0 bsize - 2 in steps of 3, , 0 csize - 2 in single steps.

how should relate size , array loop?

bsize = 960 csize = 960 barray = bytearray(fi.read()) carray= bytearray(f1.read())    in range (bsize-2,i+3):     j in range (csize-2,j+1): 

 in range (0, bsize - 2, 3): #possibly bsize - 1?     j in range (csize - 2): # possibly csize - 1?         #do thing 

that loop through first 1 incrementing i 3 every time, , j 1.

look @ tutorial or these docs learn range, it's useful!

i'm not sure if want go through bsize - 2 or it. if through, use size - 1 size - 2.

the reason you're getting error haven't defined i you're using in step. can see, python's range isn't lot of other languages' for constructs. once used it, though, it's flexible , easy use.

some examples using simple range:

>>> in range(0, 14, 3): ...    print ...  0 3 6 9 12  >>> in range(1, 5): ...     print ...  1 2 3 4  >>> in range(5): ...     print ...  0 1 2 3 4