Question

My data structure is initialized as follows:

[[0,0,0,0,0,0,0,0] for x in range(8)]

8 characters, 8 rows, each row has 5 bits for columns, so each integer can be in the range between 0 and 31 inclusive.

I have to convert the number 177 (can be between 0 and 319) into char, row, and column.

Let me try again, this time with a better code example. No bits are set.

Ok, I added the reverse to the problem. Maybe that’ll help.

chars = [[0,0,0,0,0,0,0,0] for x in range(8)]

# reverse solution
for char in range(8):
    for row in range(8):
        for col in range(5):
            n =  char * 40 + (row * 5 + col)
            chars[char][row] = chars[char][row] ^ [0, 1<<4-col][row < col]

for data in range(320):
    char = data / 40
    col = (data - char * 40) % 5
    row = ?
    print "Char %g, Row %g, Col %g" % (char, row, col), chars[char][row] & 1<<4-col

Answer 1

Okay, this looks as if you’re working with a 1×8 LCD display, where each character is 8 rows of 5 pixels.

So, you have a total of 8 * (8 * 5) = 320 pixels, and you want to map the index of a pixel to a position in the “framebuffer” decribing the display’s contents.

I assume pixels are distributed like this (shown for the first char only), your initial loops indicate this is is correct:

 0  1  2  3  4
 5  6  7  8  9
10 11 12 13 14
15 16 17 18 19
20 21 22 23 24
25 26 27 28 29
30 31 32 33 34
35 36 37 38 39

We then have:

 # Compute which of the 8 characters the pixel falls in, 0..7:
 char = int(number / 40)

 # Compute which pixel column the pixel is in, 0..4:
 col = number % 5

 # Compute which pixel row the pixel is in, 0..7:
 row = int((number - char * 40) / 5)

I used explicit int()s to make it clear that the numbers are integers.

Note that you might want to flip the column, since this numbers them from the left.