From http://www.ibm.com/developerworks/cn/opensource/os-cn-python-yield/

readfile

				
def read_file(fpath): 
    BLOCK_SIZE = 1024 
    with open(fpath, 'rb') as f: 
        while True: 
            block = f.read(BLOCK_SIZE) 
            if block: 
                yield block 
            else: 
                return