An iterator for reading a file byte by byte

Question

Is there an iterator for reading a file byte by byte?

You can use file.read(1) to read a single character from a file. If you really need to this can be typecast to a byte. — Jacob H, Feb 14 '16 at 03:04
it's pretty easy to read the file line-by-line, then iterate the characters in the line, though I know that's not exactly what you're asking. — Joseph James, Feb 14 '16 at 03:08

score 2 · Answer 1 · answered Feb 14 '16 at 03:05

There isn't an iterator for byte by byte but it is easier enough to create a generator to do it:

def bytefile(f):
    b = f.read(1)
    while b:
        yield b
        b = f.read(1)

with open('<file>', 'rb') as f:
    for b in bytefile(f):
        <do something>

But this really isn't very efficient, and it's not clear what you are trying to do.

score 0 · Answer 2 · answered Feb 14 '16 at 03:21

You can mmap the file, if you're using *nix or Windows. This should be the most efficient way to iterate over the bytes of a file:

import mmap

with open('user.py', 'rb') as f:
    # memory-map the file, size 0 means whole file
    mm = mmap.mmap(f.fileno(), 0, access=mmap.ACCESS_READ)
    for b in mm:
        print(b)
    mm.close()

An iterator for reading a file byte by byte

2 Answers2